Armitage Efficacy of the Theory of Planned Behavior

British Journal of Social Psychology (2001) 40 471ndash499 Printed in Great Britain2001 The British Psychological Society

EYcacy of the Theory of Planned BehaviourA meta-analytic review

Christopher J Armitage

Department of Psychology University of SheYeld UK

Mark Conner

School of Psychology University of Leeds UK

The Theory of Planned Behaviour (TPB) has received considerable attention inthe literature The present study is a quantitative integration and review of thatresearch From a database of 185 independent studies published up to the endof 1997 the TPB accounted for 27 and 39 of the variance in behaviourand intention respectively The perceived behavioural control (PBC) constructaccounted for signi cant amounts of variance in intention and behaviourindependent of theory of reasoned action variables When behaviour measureswere self-reports the TPB accounted for 11 more of the variance in behaviourthan when behaviour measures were objective or observed (R2s = 31 and 21respectively) Attitude subjective norm and PBC account for signi cantly more ofthe variance in individualsrsquo desires than intentions or self-predictions butintentions and self-predictions were better predictors of behaviour The subjectivenorm construct is generally found to be a weak predictor of intentions This ispartly attributable to a combination of poor measurement and the need forexpansion of the normative component The discussion focuses on ways in whichcurrent TPB research can be taken forward in the light of the present review

Since Wickerrsquos (1969) review of research examining the relationship betweenattitudes and behaviour and his conclusion that attitudes probably do not predictbehaviour social psychologists have sought to improve the predictive power ofattitudes In recent years the main approach within this area has been to developintegrated models of behaviour including additional determinants of behavioursuch as social norms or intentions (Olson amp Zanna 1993) Arguably the mostwidely researched of these models are the Theories of Reasoned Action (Ajzen ampFishbein 1980 Fishbein amp Ajzen 1975) and Planned Behaviour (Ajzen 19881991) The Theory of Planned Behaviour (TPB) is essentially an extension of theTheory of Reasoned Action (TRA) that includes measures of control belief andperceived behavioural control (see Fig 1)

Request for reprints should be addressed to Chris Armitage Centre for Research in Social Attitudes Departmentof Psychology University of SheYeld Western Bank SheYeld S10 2TP UK

471

Ajzen (eg 1991) extended the TRA to include a measure of perceivedbehavioural controlmdasha variable that had received a great deal of attention in socialcognition models designed to predict health behaviours (eg health belief modelprotection motivation theory see Armitage amp Conner 2000 Conner amp Norman1996a) Perceived behavioural control (PBC) is held to in uence both intention andbehaviour (see Fig 1) The rationale behind the addition of PBC was that it wouldallow prediction of behaviours that were not under complete volitional controlThus while the TRA could adequately predict behaviours that were relativelystraightforward (ie under volitional control) under circumstances where therewere constraints on action the mere formation of an intention was insuYcient topredict behaviour The inclusion of PBC provides information about the potentialconstraints on action as perceived by the actor and is held to explain whyintentions do not always predict behaviour1

With respect to the in uence of PBC on intention Ajzen (1991 p 188) statesthat lsquoThe relative importance of attitude subjective norm and perceivedbehavioral control in the prediction of intention is expected to vary acrossbehaviors and situationsrsquo That is in situations where (for example) attitudes arestrong or where normative in uences are powerful PBC may be less predictive ofintentions Thus Ajzen (1991) argues that the magnitude of the PBCndashintentionrelationship is dependent upon the type of behaviour and the nature of thesituation Indirect evidence for this claim has been demonstrated in studies thathave shown that measures of attitude strength (eg Sparks Hedderley amp Shepherd1992) and individual diVerences in sociability (eg Tra mow amp Finlay 1996)increase the relative predictive power of attitudes and subjective norms respect-ively In general individuals are more disposed (ie intend) to engage in behavioursthat are believed to be achievable (cf Bandura 1997)

PBC is also held to exert both direct and interactive (with behavioural intentions)eVects on behaviour This is based on the following rationale that however stronglyheld the implementation of an intention into action is at least partially determinedby personal and environmental barriers thus lsquoThe addition of perceived behav-ioural control should become increasingly useful as volitional control over behaviordecreasesrsquo (Ajzen 1991 p 185) Therefore in situations where prediction of1The authors wish to thank Russell Spears for his helpful comments with respect to the following section

Figure 1 The theory of planned behaviour

472 Christopher J Armitage and Mark Conner

behaviour from intention is likely to be hindered by the level of actual (ievolitional) control PBC should (1) facilitate the implementation of behaviouralintentions into action and (2) predict behaviour directly

In the prediction of social behaviours there are no absolutes However it isinstructive to consider Ajzenrsquos (1991) predictions by examining the impact of PBCon behaviour under both optimal (ie complete volitional control) and suboptimal(ie problems of volitional control) conditions2

In conditions of complete volitional control the intentionndashbehaviour relation-ship should be optimal and PBC should not exert any in uence on thisrelationship In contrast where the behaviour is not under complete volitionalcontrol PBC should moderate (see Baron amp Kenny 1986) the relationship betweenintention and behaviour Under such conditions greater PBC should be associatedwith stronger intentionndashbehaviour relationships In earlier versions of the TPBAjzen (eg 1985) emphasized the fact that the interaction between behaviouralintention and PBC should be independently predictive of behaviour That is underconditions where volitional control is relatively low (ie where intention is onlyweakly related to behaviour) increased PBC should facilitate the implementation ofintentions into action However in his meta-analysis of the TPB Ajzen (1991)reported that only one study had found the (marginally) signi cant (p lt 10)intentionndashPBC interaction that would support this moderator hypothesis Ajzen(1991) argued that this nding re ected the fact that linear models account well forpsychological datamdasheven if interaction terms are known to be present Yet severalmore recent studies (eg Terry amp OrsquoLeary 1995) have found signi cant PBCndashintention interactions and the present meta-analysis examines these to test thismoderator hypothesis

Following the lack of evidence for the interactive eVects of PBC on theintentionndashbehaviour relationship Ajzen (1991) argued for a direct relationshipbetween PBC and behaviour which more closely tted the available data ThusAjzen argues that under conditions where behavioural intention alone wouldaccount for only small amounts of the variance in behaviour (ie where there areproblems of volitional control) PBC should be independently predictive ofbehaviour This is based on the rationale that increased feelings of control willincrease the extent to which individuals are willing to exert additional eVort in ordersuccessfully to perform a particular behaviour In contrast under conditions ofvery high volitional control behavioural intention should be the only predictor ofbehaviour This ceiling eVect occurs because where the behaviour is relativelystraightforward exerting additional eVort to engage in the behaviour will notimpact on the actual performance of the behaviour over and above the eVects ofintention

However predictions concerning the eVects of PBC on behaviour are clouded bythe explicit assumption that PBC is an accurate representation of actual (volitional)

2Note that by lsquoproblems of volitional controlrsquo we are referring to environmental and personal constraints onbehaviour For example consider cigarette smoking here an environmental barrier might be that everyone at worksmokes a personal barrier might be the level of craving for cigarettes (for further discussion of these issues seeArmitage amp Conner 1999a 1999b)

Theory of Planned Behaviour Meta-analysis 473

control Indeed Aizen3 states that lsquoWhen PBC is inaccurate all kinds of possibilitiesopen uprsquo (I Aizen personal communication 8 November 1999) Thus where PBCand actual control are discrepant the eVect of PBC on behaviour is moreproblematic Given the extant literature on lsquoillusions of controlrsquo (eg Langer 1975Lerner 1977) it seems likely that PBC will rarely re ect actual control in a veryaccurate way In short adequate tests of predictions concerning the eVects of PBCon behaviour would either (1) experimentally manipulate individualsrsquo levels ofperceived control or (2) obtain independent measures of volition (actual control)These are matters for future research and cannot be adequately addressed usingmeta-analysis4

As we have already noted within the TPB PBC is held to aVect both intentionsand behaviour There are two further antecedents of intention subjective norm andattitude toward the behaviour which are retained from the earlier TRA Subjectivenorm refers to the individualrsquos perceptions of general social pressure to perform (ornot to perform) the behaviour If an individual perceives that signi cant othersendorse (or disapprove of) the behaviour they are more (or less) likely to intend toperform it Attitude towards the behaviour re ects the individualrsquos global positiveor negative evaluations of performing a particular behaviour In general the morefavourable the attitude towards the behaviour the stronger should be theindividualrsquos intention to perform it

The antecedents of attitude subjective norm and PBC are corresponding beliefsre ecting the underlying cognitive structure Each behavioural belief links a givenbehaviour to a certain outcome or to some other attribute such as the costincurred in performing the behaviour The attitude towards the behaviour isdetermined by the strength of these associations and by the beliefs that are salientat the time This works on the principle of Fishbein and Ajzenrsquos (1975)Expectancy-value Model the subjective value of a given outcome aVects theattitude in direct proportion to the strength of the belief Subjective norm isconsidered to be a function of salient normative beliefs While subjective normrelates to perceptions of general social pressure the underlying normative beliefs areconcerned with the likelihood that speci c individuals or groups (referents) withwhom the individual is motivated to comply will approve or disapprove of thebehaviour According to Ajzen (1991) control beliefs are the antecedents of PBCand are concerned with the perceived power of speci c factors to facilitate orinhibit performance of the behaviour Like the other beliefs the equation takesaccount of the relevance of the belief to the individual in this case by taking ameasure of the frequency of occurrence of the promoting (or inhibitory) factor3Note that lsquoAjzenrsquo recently changed his name to lsquoAizenrsquo4A number of previous meta-analyses have suggested that the TPB adds very little explained variance beyond thatwhich is explained by the TRA (eg Sutton 1998) One possibility is that as volitional control decreases thein uence of PBC on intention and behaviour increases although even studies designed to directly test thishypothesis have not produced clear-cut ndings (eg Madden Ellen amp Ajzen 1992) We therefore attempted tocode studies for lsquolevel of volitional controlrsquo On 3-point scales raters were asked to judge whether the behaviourin question was under volitional control not under volitional control or whether it was unclear Initial analysis ofcoding reliability indicated 68 agreement Following discussion this increased to 79 leaving over 20 of casesunresolved Analyses of the categories revealed no substantive diVerences between groups and no decrement inbetween-study variance An alternative proceduremdashsuggested by one of our anonymous reviewersmdashwas thereforeadopted which is set out in the Appendix


PBC will therefore be increased by salient beliefs concerning adequate resourcesand opportunities and fewer anticipated obstacles or impediments

Reviews have provided support for the TPB (eg Blue 1995 Conner amp Sparks1996 Godin 1993 Jonas amp Doll 1996 Manstead amp Parker 1995 Sparks 1994) ashave four previous meta-analyses (Ajzen 1991 Godin amp Kok 1996 HausenblasCarron amp Mack 1997 Van den Putte 1991) However these meta-analyses havebeen limited in scope and sampling For example although Van den Putte (1991)reported that PBC explained an additional 14 of the variance in intention and 4in behaviour (over and above attitude and subjective norm) discussion of issuessurrounding this nding was limited because the focus of his study was the TRA5

Ajzenrsquos (1991) meta-analysis of the TPB found an average multiple correlation ofattitude subjective norm and PBC with intention of R = 71 (19 correlations) andan average multiple correlation of R = 51 (17 correlations) for prediction ofbehaviour from intention and PBC However these analyses considered only thedirect antecedents of intention and behaviour and were based upon a limited dataset including studies that have never been published Godin and Kokrsquos (1996)meta-analysis found that PBC contributed a mean additional 13 of variance to theprediction of intentions and 12 to the prediction of behaviour However Godinand Kok considered only health behaviours and reported values that were derivedonly from studies that reported the relevant data The tendency for authors toreport only signi cant ndings may have in ated the reported values (cf Rosenthal1979) Finally Hausenblas et al (1997) report a meta-analysis on applications of theTRA and TPB to exercise behaviour They conclude that the TPB is more usefulthan the TRA but base this conclusion solely on the magnitude of correlationsbetween PBC intention and behaviour

More generally previous meta-analyses of the TRATPB have tended to analysedata from participants more than once have failed to report reliability statistics andtreated all studies as equivalent with no attempt to weight their data in favour ofstudies with more participants However in spite of these weaknesses evidencefrom narrative and meta-analytic reviews suggests that the TPB is a useful modelfor predicting a wide range of behaviours and behavioural intentions The presentmeta-analysis aims to overcome some of the methodological weaknesses ofprevious meta-analyses and to focus on several of the issues in current TPBresearch

Issues surrounding the TPB

Self-report

Behavioural decision-making models such as the TRA and TPB have tended to relyon self-reports despite evidence to suggest the vulnerability of such data toself-presentational biases (eg Gaes Kalle amp Tedeschi 1978) To a great extentthis has been ignored in the literature pertaining to the TRATPB in spite of thethreat to the validity and reliability of the models Beck and Ajzen (1991) providedan exception applying the TPB and a MarlowendashCrowne Social Desirability Scale5Indeed this analysis was presented in the introduction to his meta-analysis of the TRA


(SDS Crowne amp Marlowe 1964) to predicting dishonest intentions and actions(cheating shoplifting and lying) SDS scores were entered into a regressionequation and accounted for 5 of the variance in intentions providing someevidence to suggest that individuals may provide socially desirable answers in termsof their attitudes and intentions6 Six months later TPB variables were able toaccount for between 12 and 55 of the variance in self-reported behaviour Incontrast however Armitage and Conner (1999c) reported few eVects of socialdesirability on relationships between TPB components

More closely related to the concerns of the present study Hessing ElVers andWeigel (1988) examined the TRA in relation to tax evasion and contrastedself-reports with oYcial documentation Findings indicated that attitudes andsubjective norms signi cantly correlated with self-reported behaviour but did notcorrelate with documentary evidence in spite of considerable eVort to maintain theanonymity of respondents The implication was that self-reports of behaviour wereunreliable compared with more objective behaviour measures (see also Armitage ampConner 1999a 1999b Norwich amp Rovoli 1993 Pellino 1997) In terms of thepresent study we expected TPB variables (ie intention and PBC) to predictself-reported and observed behaviour but that prediction of objective behaviourwould be less accurate

Control

It has already been noted that the diVerence between the TRA and TPB lies in thecontrol component of the TPB Ajzen (1991) argues that the PBC and self-eYcacyconstructs are interchangeable However several authors (eg Terry 1993) havesuggested that self-eYcacy and PBC are not entirely synonymous For exampleBandura (1986 1992) has argued that control and self-eYcacy are quite diVerentconcepts Self-eYcacy is more concerned with cognitive perceptions of controlbased on internal control factors whereas PBC also re ects more general externalfactors Researchers such as de Vries Dijkstra and Kuhlman (1988) haveadvocated the use of measures of self-eYcacy as opposed to PBC in the predictionof intentions and behaviour Further Dzewaltowski Noble and Shaw (1990) in acomparison of the theories of reasoned action planned behaviour and socialcognitive theory found that self-eYcacy rather than PBC had a direct impact onbehaviour

Terry and colleagues have closely examined the distinction between PBC andself-eYcacy For safer sex behaviours White Terry and Hogg (1994) reported thatPBC only had an eVect on a behavioural measure of discussing the use of condomswith any new partner while self-eYcacy had a strong eVect on intentions to discussand intentions to use condoms Consonant with White et al (1994) Terry andOrsquoLeary (1995) found that self-eYcacy only predicted intentions while PBCpredicted exercise behaviour These studies therefore provide support for adistinction between self-eYcacy and PBC (see also Manstead amp van Eekelen 1998)

6However this nding must be interpreted with extreme caution as SDS measures were not taken at the same timeas the six-month self-report of behaviour Perhaps more importantly SDS also rely on self-report


More recently Sparks Guthrie and Shepherd (1997) have proposed a distinctionbetween lsquoperceived diYcultyrsquo and lsquoperceived controlrsquo (see also Chan amp Fishbein1993) These authors argue that items which tap lsquoperceived diYcultyrsquo are both moremeaningful to participants and are closer to Ajzenrsquos (1991) original conceptualiz-ation of PBC Sparks et al (1997) report two studies to support their position Intheir study 1 although they found diVerences in the pattern of intercorrelationsneither lsquoperceived diYcultyrsquo nor lsquoperceived controlrsquo predicted intention In study 2lsquoperceived diYcultyrsquo independently predicted intention but lsquoperceived controlrsquo didnot These ndings were interpreted as evidence to support the use of lsquoperceiveddiYcultyrsquo over lsquoperceived controlrsquo Armitage and Conner (1999a 1999b) havecritiqued this approach arguing that asking individuals about the lsquoeasersquo orlsquodiYcultyrsquo of performing a particular behaviour does not allow discriminationbetween ease or diYculty in relation to external (eg lsquoavailabilityrsquo) and internal (eglsquocon dencersquo) factors Moreover the Sparks et al study employed a cross-sectionaldesign with no data to test the eVects on subsequent behaviour which formed thebasis of Terry and colleaguesrsquo distinction Armitage and Conner (1999a 1999b) alsoprovide evidence to support a distinction between self-eYcacy and lsquoperceivedcontrol over behaviourrsquo utilizing measures that do not rely on perceived ease ordiYculty The present study sought meta-analytic evidence to support this position

Behavioural intentions

The intention construct is central to both the TRA and TPB Intentions areassumed to capture the motivational factors that in uence a behaviour and toindicate how hard people are willing to try or how much eVort they would exert toperform the behaviour (Ajzen 1991 p 181) In applications of the TRATPBresearchers have not always employed measures that clearly tap the intentionconstruct For example Sheppard Hartwick and Warshawrsquos (1988) review of theTRA argued for the need to consider both behavioural intentions and self-predictions when predicting behaviour Warshaw and Davis (1985) noted a numberof diVerent ways in which intentions had been measured and distinguishedmeasures of behavioural intentions (eg lsquoI intend to perform behaviour xrsquo) frommeasures of self-predictions (eg lsquoHow likely is it that you will perform behaviourxrsquo) Sheppard et al (1988) went on to argue that self-predictions should providebetter predictions of behaviour as they are likely to include a consideration of thosefactors which may facilitate or inhibit performance of a behaviour as well as aconsideration of the likely choice of other competing behaviours Sheppard et alrsquosmeta-analysis supported this view measures of self-predictions were found tohave stronger relationships with behaviour (mean r = 57) than did behaviouralintentions (mean r = 49) although attitude and subjective norm accounted formore of the variance in intentions (mean R = 73) than self-predictions (meanR = 61)

In the TPB the PBC construct should tap perceptions of the factors that mayfacilitate or inhibit performance of behaviour One might therefore expect littlediVerence in the predictive power of intentions vs self-predictions once PBC istaken into account More speci cally the relationship between PBC and behaviour


should be stronger when intention (as opposed to self-prediction) measures areused because intention measures do not take facilitatinginhibiting factors intoaccount

Beyond this Bagozzi (1992) has suggested that attitudes may rst be translatedinto desires (eg lsquoI want to perform behaviour xrsquo) which then develop intointentions to act which direct action From this perspective one might expect thatdesires would inform intentions upon which behavioural self-predictions are partlybased Given that desires take no account of facilitatinginhibiting factors PBCshould contribute more unique variance to the prediction of behaviour whenmeasures of desires are employed than self-predictions Congruent with the viewthat desires do not take account of facilitatinginhibiting in uences on behaviourPBC should be more closely associated with self-predictions than with desires Onthe other hand intentions are held to mediate the relationship between desires andself-predictions suggesting that eVects associated with intentions will fall betweenthe desire and self-prediction ndings The present meta-analysis considers the roleof intentions desires and self-predictions in the context of the TPB

Subjective norms

The normative component was the last addition to the TRA (Fishbein amp Ajzen1975) and several authors have argued that it is the weakest component Forexample Sheppard et al (1988) and Van den Puttersquos (1991) meta-analyses of theTRA found that the subjective norm component was the weakest predictor ofintentions (see also Godin amp Kok 1996) As a result several authors havedeliberately removed subjective norms from analysis (eg Sparks ShepherdWieringa amp Zimmermanns 1995) While these ndings could merely re ect thelesser importance of normative factors as determinants of intentions in thebehaviours studied Tra mow and Finlay (1996) suggest that this is unlikely Across30 behaviours they found evidence to suggest a distinction between individualswhose actions are driven primarily by attitudes and those whose actions are drivenprimarily by subjective norms7 In addition across several diVerent types ofbehaviour variables thought to tap diVerent facets of normative conduct (egdescriptive and moral norms) have been found to be independently predictive ofintentions (eg Beck amp Ajzen 1991 Conner Martin Silverdale amp Grogan 1996for a review see Conner amp Armitage 1998) The most likely explanation for poorperformance of the subjective norm component lies in its measurement manyauthors use single item measures as opposed to more reliable multi-item scales (egNunnally 1978) The present meta-analysis therefore considered type of measure-ment as a moderator of subjective normndashintention correlations

Aims

The aims of the present meta-analysis were vefold (1) to test the overall eYcacyof the TPB (2) to assess the predictive validity of the TPB in relation to observed

7See also Prislin and Kovrlija (1992) for an application of the TPB to high- and low self-monitors


or self-reported behaviour (3) to consider diVerences in the conceptualization ofintentions and to assess the evidence for discriminant validity between theconstructs (4) to examine the role of PBC as opposed to self-eYcacy or lsquoperceivedcontrol over behaviourrsquo and consider the proposed intentionndashPBC interaction and(5) to consider measurement adequacy as a moderator of the subjective normndashintention relationship given that this construct has been found to be the weakestpredictor in both the TRA and TPB

Method

Selection of stud ies

Mullen (1989) presents several useful strategies for the retrieval of studies for meta-analysis In termsof the present study the main approaches used were ancestry and descendancy abstracting serviceson-line computer searches the lsquoinvisible collegersquo and browsing In total references to 161 journalarticles and book chapters testing the TPB (up to the end of 1997) were found

The decision to include only published articles renders the present meta-analysis susceptible topublication bias The publication bias refers to the assumption that studies with signi cant ndingsare more likely to be submitted for publication Several studies have examined this phenomenon (egGreenwald 1975 Rosenthal 1984 White 1982) although ndings are inconsistent Related to thisthe lsquo le drawer problemrsquo (Rosenthal 1979) refers to the possibility that all published articles are theresult of Type I errors whereas all non-published (ie le drawer) studies are the remaining 95Reliability of the data included in the present study is assessed using Rosenthalrsquos (1984) fail-safenumber (the number of studies required to nullify the present ndings) All relationships in thepresent study exceed this tolerance level unless otherwise stated

Tables reporting meta-analytic data also include 2 values These allow assessment of between-study variance (ie the variability of (in this case) eVect sizes around the mean presented) All 2

values in the present study indicate considerable variability around the mean indicating that evenmoderator analysis failed to reduce between-study variance to non-signi cance Used in conjunctionwith Rosenthalrsquos fail-safe number it is possible to assert that the present ndings are robust (ierequire large numbers of additional studies to overturn them) but are subject to variability around themean

Characteristics of stud ies

The 161 articles contained 185 independent empirical tests of the TPB Of these 44 containedprospective self-reported behaviour measures and 19 prospective measures of behaviour that wereindependently rated or were objective (eg taken from records)8

Self-eYcacy PBC and lsquoperceived control over behaviourrsquo The present meta-analysis distinguishesbetween three types of PBC measure self-eYcacy PBC and lsquoperceived control over behaviourrsquoCongruent with Armitage and Conner (1999a 1999b) self-eYcacy was de ned as lsquocon dence in onersquosown ability to carry out a particular behaviourrsquo perceived control over behaviour was de ned aslsquoperceived controllability of behaviourrsquo and PBC was de ned as the perceived ease or diYculty ofperforming behaviour (Ajzen 1991) and also included studies that utilized measures of bothself-eYcacy and perceived control over behaviour in multiple-item scales

Studies were coded as measuring self-eYcacy if they included items such as lsquoI believe I have theability to rsquo lsquoTo what extent do you see yourself as being capable of rsquo lsquoHow con dent are you

8Note that only prospective measures of behaviour were included in the present meta-analysis This is because ameasure of behaviour taken contemporaneously with intention is actually a measure of past behaviour Measuresof past behaviour have been shown to contribute unique variance to the prediction of future behaviour over andabove TPB variables introducing a possible confound (for reviews see Conner amp Armitage 1998 Sutton 1994)


that you will be able to rsquo and lsquoIf it were entirely up to me I am con dent that I would be ableto rsquo (N of studies = 28) lsquoPerceived control over behaviourrsquo was coded when items such aslsquoWhether or not I do x is entirely up to mersquo lsquoHow much personal control do you feel you have over rsquo and lsquoHow much do you feel that whether you do x is beyond your controlrsquo were employed(N = 7) Items that assessed perceived ease or diYculty were not included when coding forself-eYcacy or lsquoperceived control over behaviourrsquo Where studies employed mixed measures (ie anycombination of the above or lsquoeasyndashdiYcultrsquo items) these were coded as lsquoPBCrsquo (N = 101)

Desires intentions and self-pred ictions Desires intentions and self-predictions were codedaccording to the criteria discussed in Bagozzi (1992) Fishbein and Stasson (1990) Norman and Smith(1995) Sheppard et al (1988) and Warshaw and Davis (1985) Brie y lsquodesirersquo was coded if studiesemployed items such as lsquoI want to perform behaviour xrsquo lsquoself-predictionrsquo was coded for measures suchas lsquoI will perform behaviour xrsquo or lsquoHow likely is it that you will perform behaviour xrsquo and lsquointentionrsquowas coded for studies that employed only measures such as lsquoI intend to perform behaviour xrsquo Wherestudies employed some combination of the above these were coded as lsquomixedrsquo measures We wereable to locate 88 studies that used mixed measures of behavioural intentions 20 with measures ofintention 40 with measures of self-prediction and six of desire

Subjective norms Studies were also coded for measurements of the subjective norm componentThese fell into six categories multiple-item scale (N = 32) single item (N = 52) general socialpressure multiplied by motivation to comply (N = 14) normative beliefs9 as direct predictors ofintention (N = 26) social support (N = 1) and unspeci ed (N = 12)

Analyses

Analyses are based on bivariate correlations where the appropriate statistics were not reported in thepublished article the authors were contacted and several have generously supplied copies of theircorrelation matrices This allowed us to run additional analyses

For the purpose of analysis rs were converted to Fisher z scores weighted by sample size (N 3)before a mean Fisher z was calculated (see Hedges amp Olkin 1985) The weighted mean Fisher zs werethen converted back to rs for the purpose of reporting the results R2 change values (for eVects ofPBC controlling for TRA variables) were converted to r and combined in the same way as bivariatecorrelations

Comparisons between correlation coeYcients were conducted using Cohenrsquos (1977) qs statisticwhich evaluates diVerences in the magnitude of Fisher z For samples with unequal Ns a harmonicmean (n ) was used Note however that this only provides an estimate of diVerences betweenmagnitude of correlation coeYcients because the technique ignores dependencies between variablesIn the case of the TPB most of the interesting comparisons involve diVerences between correlationsthat hold intention in common

It has been noted that the meta-analyses of Godin and Kok (1996) and Sheppard et al (1988) canbe criticized for analysing groups of participants more than once For example in the Sheppard et al(1988) meta-analysis two groups of participants from Warshaw and Davis (1985) were treated asindependent tests of the TRA and included 18 times in the analysis Clearly this threatens the validityof meta-analysis In order to avoid this where studies examined more than one behaviour with onegroup of participants (eg Madden Ellen amp Ajzen 1992) the rs were converted to Fisher zs andmeta-analysed in their own right before inclusion in the main data set

Finally because meta-analytic data tend to be based on large sample sizes even the smallestcorrelations are likely to reach statistical signi cance Cohen (1992) presents a useful guide tointerpreting the magnitude of eVect sizes medium eVect sizes are de ned as those that approximatethe average eVect sizes across a variety of elds of research Small eVect sizes are lsquonoticeably smallerthan medium but not so small as to be trivialrsquo large eVect sizes are lsquothe same distance above medium

9By lsquonormative beliefsrsquo we are referring to a summed scale derived from the product referent beliefs andmotivations to comply


as small was below itrsquo (Cohen 1992 p 156) These eVect size categories equate with correlations of10 (small) 30 (medium) and 50 (large) and this provides a useful heuristic that acts as a standardof comparison

Results

Overall nd ings

Average correlations and multiple correlations (all weighted by sample size N 3)are reported for TPB component relationships in Table 1 For all ndings (unlessotherwise stated) all fail-safe numbers far exceed Rosenthalrsquos (1984) recommendedtolerance level Across all behaviours the average multiple correlation of intentionand PBC with behaviour is 52 accounting for 27 of the variance (R2 = 27)Overall PBC adds an average of 2 to prediction of behaviour over and aboveintention Given that Ajzen (1991) argues that for behaviours where there are noproblems of volitional control PBC will contribute nothing to the prediction ofbehaviour and this nding supports the usefulness of the PBC construct inpredicting behaviour

The averaging multiple correlation of attitude subjective norm and PBC withintention is R = 63 accounting for 39 of the variance (R2 = 39) Not only is thePBCndashintention correlation strong (r = 43) it independently accounts for 6 of thevariance controlling for attitude and subjective norm Congruent with severalauthors who do not include a subjective norm measure (eg Sparks ShepherdWieringa amp Zimmermanns 1995) the subjective normndashintention correlationis signi cantly weaker than the other relationships with intention (comparedto attitudendashintention correlation qs = 19 p lt 01 compared to PBCndashintention

Table 1 Average component relationships for all tests of the TPB

Relationship N of tests Ra R2 Fail-safe N 2

Multiple correlation (BI+PBC) with behaviour 63 52 27 65347 648BIndashbehaviour correlation 48 47 22 26235 396PBCndashbehaviour correlation 60 37 13 27498 677 variance added by PBC to behaviour 66 14 02 3815 285Multiple correlation (ATT+SN+PBC) with BI 154 63 39 986974 3231ATTndashBI correlation 115 49 24 326497 1050SNndashBI correlation 137 34 12 201774 1167PBCndashBI correlation 144 43 18 378681 2224 variance added by PBC to BI 136 24 06 89753 1086Behavioural beliefndashATT correlation 42 50 25 34201 413Normative beliefndashSN correlation 34 50 25 20794 451Control beliefndashPBC correlation 18 52 27 6174 269

plt001Note aWeighted by sample size BI=behavioural intention PBC=perceived behaviouralcontrol ATT=attitude SN=subjective norm


correlation qs = 11 p lt 05) Although this does not present suYcient evidence towarrant discarding the construct it does perhaps indicate that it is the part of theTPB that most requires further study We return to this issue later

In addition to these ndings Table 1 also displays the correlations betweenbelief-based and direct measures of attitude subjective norm and PBC10

Congruent with Fishbein and Ajzenrsquos (1975) formulation that behavioural- andnormative-belief measures inform attitude and subjective norms respectively bothare strongly correlated with each other (both rs = 50) Moreover there was supportfor Ajzenrsquos (1991) expectancy-value basis to control beliefs these correlated r = 52with PBC Perhaps more importantly all the correlations may be classi ed asrepresenting lsquomediumrsquo to lsquolargersquo eVect sizes (Cohen 1992)

Self-report vs observed behaviour

Table 2 presents multiple correlations of intention and PBC contrasting self-reported and observed behaviour The TPB accounts for large highly signi cantproportions of the variance in prospective measures of both observed (R2 = 20)and self-reported (R2 = 31) behaviour Although this diVerence is signi cant(qs = 14 p lt 01) it is encouraging that the TPB can account for considerableproportions of the variance in actual behaviour (ie a medium-large eVect size) andprovides further evidence of the eYcacy of the model


Table 3 contrasts the diVerent measures that have been employed to tapbehavioural intentions desires intentions and self-predictions (see Method forde nitions) The multiple correlation of attitude subjective norm and PBC withdesire was signi cantly stronger than with either intention (qs = 27 p lt 01)self-prediction (qs = 26 p lt 01) or the mixed measure (qs = 19 p lt 05) Inaddition the role of PBC diVered depending on whether desire self-prediction orintention was the dependent variable For self-prediction PBC contributed anadditional 7 of variance over and above attitude and subjective norm The10All belief-based measures are those which follow the expectancy-value format in other words summed scalesderived from outcome beliefs evaluations (behavioural beliefs) referent beliefs motivations to comply(normative beliefs) and facilitatoryinhibitory beliefs power (control beliefs)

Table 2 Meta-analysis of self-reported vs observed behaviour


TPB Self-reported behaviour 44 55 31 37695 509TPB Observed behaviour 19 44 20 3762 86

plt001Note aWeighted by sample size TPB=multiple correlation of intention and PBC


corresponding values for desires and intentions were 2 and 8 respectivelyConsonant with predictions the implication is that the formation of intentions andself-predictions are relatively more contingent on an assessment of perceivedbehavioural control than are desires

Consistent with this position intentions and self-predictions were strongerpredictors of behaviour than desires (qs = 07 12 respectively both ps lt 05)when PBC was included as a predictor Furthermore PBC contributed moreunique variance to prediction of behaviour when a measure of desire was used(R2

change = 06) than when either intention (R2change = 01) or self-prediction

(R2change = 02) was included Thus PBC is a less important determinant of

behaviour when measures of intention or self-prediction are employed

Control

Findings relating to the impact of diVerent conceptualizations of control onintention and behaviour are presented in Table 4 Self-eYcacy and PBC have acomparable level of correlation with both intention (both rs = 44) and behaviour(rs = 35 and 40 respectively) The corresponding correlations for perceivedcontrol over behaviour were signi cantly weaker for both behaviour (qss = 18 and24 ps lt 01 for comparisons with self-eYcacy and PBC respectively) and intention(qss = 24 ps lt 01 for both comparisons) Thus self-eYcacy and PBC correlatewith intention and behaviour signi cantly more strongly than perceived controlover behaviour

Controlling for intention self-eYcacy and PBC contribute an additional 2 toexplained variance in behaviour The corresponding value for perceived controlover behaviour was 003 although this must be interpreted with caution as onlytwo additional studies reporting null results would overturn this nding (ie it failed

Table 3 Meta-analysis of intention vs desire or self-prediction


varianceadded by

PBC

lsquoMixedrsquo PBC Behaviour 36 52 27 28665 390 3Intention PBC Behaviour 8 57 33 914 58 1Self-predictions PBC Behaviour 16 54 29 5750 246 2Desire PBC Behaviour 3 47 22 105 7 7TPB lsquoMixedrsquo 88 64 42 486334 2688 6TPB Intention 20 57 32 17239 246 8TPB Self-predictions 40 58 34 68262 401 7TPB Desires 6 73 54 1201 21 2

plt05 plt001Note aWeighted by sample size TPB=multiple correlation of attitude subjective norm andPBC


to achieve Rosenthalrsquos (1984) tolerance level) For prediction of intentionself-eYcacy explains an additional 7 and PBC an additional 5 of explainedvariance Perceived control over behaviour contributed an additional 1 althoughonly eight additional studies reporting null results would be required to render this nding non-signi cant

We were able to locate 19 studies that appropriately tested the intentionperceived control (ie PBC self-eYcacy or perceived control over behaviour)interaction hypothesis Of these studies nine (47) reported evidence of asigni cant interaction eVect In each case higher levels of PBC were associatedwith stronger intentionndashbehaviour relationships However it is diYcult to draw rm conclusions from such empirical data because relatively few of the studiesemploying the TPB actually reported tests of the interaction eVect (30 19 out of63) Ajzen (1991 p 188) suggests that failure to nd an eVect may be attributableto the fact that linear models provide good accounts of psychological data evenwhen interaction eVects are known to be present Also if perceived control (iePBC self-eYcacy perceived control over behaviour) is unrelated to actual controlthe extent to which perceived control would moderate intentionndashbehaviourrelationships or show a direct link to behaviour is unclear

Subjective norms

The measurement explanation of the weak predictive power of subjective normsrelates to the fact that norms are typically measured by a single item despite the

Table 4 Average controlndashintention and controlndashbehaviour relationships

Relationship N of tests ra Fail-safe N 2 variance

addedb

Self eYcacy Behaviour 13 35 1092 25 2PBC Behaviour 40 40 13904 582 2Perceived control over

Behaviour Behaviour 6 18 69 19 lt1Self-eYcacy Intention 28 44 17113 365 7PBC Intention 101 44 198869 1697 5Perceived control over

Behaviour Intention 7 23 174 18 1

plt05 plt01 plt001Note aWeighted by sample size b Variance refers to the percentage variance added by theperceived control construct (ie self-eYcacy PBC or perceived control over behaviour) to theprediction of intention or behaviour controlling for other TPB variables (ie attitude andsubjective norm for prediction of intention intention for prediction of behaviour) Fail-safevalues are calculated separately for these values note that perceived control over behaviourrelationships with intention and behaviour fail to exceed Rosenthalrsquos (1984) acceptable tolerancelevel


potentially low reliability of such measures From Table 5 multiple-item measuresof subjective norm and normative beliefs had signi cantly stronger correlationswith intention than any of the other measures (qs = 09ndash15 all ps lt 05) The weakpredictive power of the subjective norm component within the TPB may thereforebe partially accounted for by weaknesses in measurement

Although it is perhaps unsurprising that multiple measures of subjective normsare more strongly related to intentions the impact of normative beliefs on intentionshould be mediated through the subjective norm component Equivalent subjectivenormndashintention and normative beliefndashintention correlations of 38 and a normativebeliefndashsubjective norm correlation of 50 (cf Table 1) suggest that the twomeasures closely map onto one another Subjective norms are posited as globalperceptions of social pressure that derive from judgments of social pressure fromsalient others weighted by the motivation to comply with these groups orindividuals That the two correlate strongly implies that the operationalization ofnormative beliefs represents an accurate analysis of the process underlying theformation of global perceptions of subjective norm

Discussion

The present meta-analysis provides evidence supporting the use of the TPB forpredicting intention and behaviour although the prediction of self-reportedbehaviour is superior to observed behaviour Moreover there is some evidence fordiscriminant validity between desire intention and self-prediction and for adistinction between self-eYcacy and perceived control over behaviour Finallysubjective norm shows a reasonably strong relationship with intention whenappropriately measured with multiple-item scales

Overall nd ings

The present meta-analysis of the TPB compares favourably with previous meta-analyses The present study found R = 52 (R2 = 27) for the multiple correlation of

Table 5 Meta-analysis of single vs multiple-item measures of subjective norms inregression with intentions

Measure N of tests ra Fail-safe N 2

Multiple items 32 38 11403 237Single item 52 28 17936 270Subjective norm Motivation to comply 14 30 1195 45Social support 1 25 [ndash] [ndash]Normative beliefs 26 38 9987 213Unspeci ed 12 45 4095 188

plt001Note aWeighted by sample size


intention and PBC with behaviour previous meta-analyses have reported similar ndings (range of R = 46ndash58) Further congruent with these studies PBC wasfound to contribute uniquely to the prediction of behaviour demonstrating theeYcacy of the PBC construct Similarly the intentionndashbehaviour correlation fromthe present meta-analysis is comparable with those of recent meta-analyses devotedto intentionndashbehaviour relations The intentionndashbehaviour correlation in thepresent meta-analysis is r = 47 Randall and WolV (1994) report a correspondingrelationship of 45 (98 studies) while Sheeran and Orbell (1998) reported a meancorrelation of 44 (28 studies of condom use)

Further support for the eYcacy of the TPB over the TRA is provided by themultiple correlation of attitude subjective norm and PBC with intention The ndings of the present meta-analysis are comparable with those of previous studies(Rs = 64ndash71) More importantly from the present meta-analysis PBC addsmdashonaveragemdash6 to the prediction of intention over and above attitude and subjectivenorm Therefore it would appear that PBC in uences behaviour directly andindirectly independent of TRA variables and therefore represents a useful additionto the TRA

Self-report vs objective behaviour

It is clear that many TPB studies do not employ prospective designs or measurebehaviour Where behaviour is measured it is typically through self-reportCongruent with Hessing et al (1988) intention and PBC were better predictors ofself-reported behaviour than observed behaviour Clearly this is not a problemspeci c to the TRATPB but provides indication of the wider debate within socialpsychology

Potentially however this may simply re ect the fact that measurement corre-spondence is typically maximized where subjective measures of behaviour are used(cf Fishbein 1980) For example in a study of low-fat diet consumption Armitageand Conner (1999a) reported a comparable discrepancy between self-reportedbehaviour (eg lsquoI ate a low-fat dietrsquo) and a more objective assessment of behaviour(validated measure of percentage of calories derived from fat) While the diVerencebetween the two may represent a subjectivendashobjective distinction it may alsore ect the fact that the subjective measure of behaviour directly mapped onto theprior measure of intention whereas the objective measure could not Sutton (1998)has suggested that showing participants the measure of behaviour on which theywill later be assessed is one way of circumventing such problems Researchersshould be cognizant of the problems of self-report data and wherever possibletake accurate multiple measures of actual behaviour

Desire intention and self-pred iction

The present study provides some support for work proposing a distinction betweenintention desire and self-prediction (eg Bagozzi 1992) TPB variables were mostclosely associated with desires although PBC contributed relatively little additional


variance In turn desires were the weakest predictors of behaviour with PBCcontributing the most additional variance PBC contributed most additionalvariance to the explanation of intention and self-prediction and contributed leastto prediction of behaviour when intention and self-prediction were statisticallycontrolled These ndings can be accounted for by the fact that PBC takes accountof factors that may facilitate or inhibit behaviour under such circumstances onewould expect little diVerence between intention and self-prediction

Overall the present ndings provide some support for Bagozzirsquos (1992) positionintentions and self-predictions were superior predictors of behaviour than desiresattitudes subjective norm and perceived control (ie self-eYcacy PBC or perceivedcontrol over behaviour) were the best predictors of desires Thus individuals may rst translate their attitudes into desires taking perceptions of social pressure and(to a lesser extent) control into account However these desires are weak directpredictors of behaviour but may instead be mediated by intentions or self-predictions or may co-determine behaviour with perceived control Furtherevidence for this is reported in Bagozzi and Kimmel (1995) who showed that theimpact of attitudes on intention was almost entirely mediated by desires Futurework is required to test the proposed causal relationships between these variables

Perceptions of control

The present meta-analysis found diVerences between measures of PBC self-eYcacyand perceived control over behaviour Self-eYcacy and PBC were signi cantlymore strongly correlated with both intention and behaviour than was perceivedcontrol over behaviour Congruent with this analysis of the proportion ofadditional variance explained indicated that the ndings for perceived control overbehaviour were both weak and unreliable In general self-eYcacy accounted for themost additional variance in intention and both PBC and self-eYcacy accounted forequivalent proportions of variance in behaviour The implication is that individualsform intentions that they are con dent they can enact (ie those they perceiveself-eYcacy over) and that translation of intention into action may be facilitatedboth by self-eYcacy and an assessment of more external factors tapped by PBC

The analyses concerning the proportion of additional explained variance con-tributed by perceived control over behaviour were shown to be unreliable morestudies are required that more fully investigate this construct Indeed the possibilityexists that the predicted diVerential eVects of self-eYcacy and perceived controlover behaviour may vary as a function of behaviour studied (see Armitage ampConner 1999a 1999b Manstead amp van Eekelen 1998) However where the datawere reliable perceived control over behaviour was signi cantly more weaklyrelated to intention and behaviour The ndings also suggest that self-eYcacy andPBC are both useful predictors of intention and behaviour While there is noclear evidence for which is to be preferred self-eYcacy is more clearly de nedand operationalized than is PBC (cf Bandura 1997) which consists of lsquomixedmeasuresrsquo (see Method) Moreover while self-eYcacy and PBC account forequivalent proportions of the variance in behaviour self-eYcacy explains some-what more of the variance in intention than does PBC The implication is that


self-eYcacy should be the preferred measure of lsquoperceived controlrsquo within the TPBbut further research is required that more fully evaluates the impact of diVerentoperationalizations of perceived control on intention and behaviour

In addition researchers have paid relatively little attention to precisely what PBCis tapping up to the end of 1997 only 18 published studies reported controlbeliefndashPBC relationships Given the role of PBC as a powerful determinant of bothintention and behaviour further exploration of both the nature and antecedents ofthe PBC construct is clearly required For example a recent study by Armitage andConner (1999a) provides some evidence to suggest that control beliefs (asconceptualized by Ajzen 1991) are the antecedents of self-eYcacy but correlateonly weakly with perceived control over behaviour

Subjective norms

Several researchers have argued that the subjective norm component of the TPB isinadequate and rarely predicts intention and so have removed it from analysis (egSparks Shepherd Wieringa amp Zimmermanns 1995) The present meta-analysisprovides some support for this view subjective norm was the TPB componentmost weakly related to intention However when type of measure was used as amoderator the poor performance of the subjective norm component was shown tobe a function of measurement Clearly this component requires further empiricalattention and the present study points to measurement as its principal weaknessgiven that the majority of TPB studies have used single-item measures Beyond thisa number of authors have argued that the way in which norms are conceptualizedwithin the TRATPB framework fails to tap important facets of social in uence(eg Conner amp Armitage 1998 Terry Hogg amp White 1999)

Some researchers have suggested a reconceptualization of the mechanism bywhich normative pressure is exerted Tra mow and Finlay (1996) have argued thatthe weakness in the subjective norm component stems from a minority ofindividuals whose actions are driven primarily by perceived social pressureAlthough they provide some evidence to support this view (see also DeBono ampSnyder 1995) it seems unlikely that the majority of peoplersquos behaviour isunaVected by social pressure There is also evidence to suggest that alternativeconceptualizations of norms exert independent eVects on intentions controlling forsubjective norms

Subjective norm is operationalized as a global perception of social pressure eitherto comply with the wishes of others or not (Ajzen 1991) However social pressureis rarely so direct or explicit leading a number of researchers to suggest alternativeconceptualizations For example Terry and colleagues (eg Terry amp Hogg 1996Terry et al 1999 Terry Hogg amp White 2000 White et al 1994) have drawn onSelf-categorization and Social Identity Theories (see Hogg amp Abrams 1988Turner 1985) Speci cally Terry and colleagues have shown that identi cation witha behaviourally relevant group moderates the eVects of group norm on intention(Terry amp Hogg 1996) In addition they present some evidence to support adistinction between group- and subjective-norms (Terry et al 1999 cf Deutschand Gerardrsquos (1995) distinction between informational and normative in uence)


Related work has investigated a number of diVerent types of norm CialdiniKallgren and Reno (1991) distinguish between personal descriptive and injunctivenorms Injunctive norms map onto subjective norms Personal norms have beenoperationalized as either self-identity or moral norms (see Conner amp Armitage1998) A number of studies have shown that self-identity explains additionalproportions of the variance in intentions over and above TPB variables (egArmitage amp Conner 1999a 1999b Sparks amp Shepherd 1992 for a review seeConner amp Armitage 1998) There is also evidence to support the inclusion of moral(eg Beck amp Ajzen 1991 Conner amp Armitage 1998) and descriptive (eg Conneret al 1996) norms within the TPB Further research is required to test thesuYciency of such additional variables by testing them against adequate measuresof subjective norm

Conclusions

The present meta-analysis provides support for the eYcacy of the TPB as apredictor of intentions and behaviour Although prediction is superior forself-reported than observed behaviour the TPB is still capable of explaining 20of the variance in prospective measures of actual behaviour (ie a medium to largeeVect size) The present ndings therefore corroborate those of previous TPBmeta-analyses as well as expanding on some of the theoretical debate surroundingthe model The present study showed that PBC independently predicted intentionsand behaviour in a wide number of domains There was also evidence to suggestthat measures of intention self-prediction and desires possess discriminant validityalthough only relatively weak evidence for the proposed self-eYcacyndashperceivedcontrol over behaviour distinction Finally work on additional normative variables(eg moral or descriptive norms) may increase the predictive power of thenormative component of the model

References

Note References marked with indicate TPB studies used in the meta-analysisAjzen I (1985) From intentions to action A theory of planned behavior In J Kuhl amp J Beckman

(Eds) Action control From cognitions to behaviors (pp 11ndash39) New York SpringerAjzen I (1988) Attitudes personality and behavior Milton Keynes Open University PressAjzen I (1991) The theory of planned behavior Organizational Behavior and Human Decision Processes

50 179ndash211Ajzen I amp Driver B L (1992) Application of the theory of planned behavior to leisure choice

Journal of Leisure Research 24 207ndash224Ajzen I amp Fishbein M (1980) Und erstand ing attitudes and pred icting social behavior Englewood CliVs

NJ Prentice-HallAjzen I amp Madden T J (1986) Prediction of goal directed behavior Attitudes intentions and

perceived behavioral control Journal of Experimental Social Psychology 22 453ndash474Armitage C J amp Conner M (1999a) The theory of planned behaviour Assessment of predictive

validity and lsquoperceived controlrsquo British Journal of Social Psychology 38 35ndash54Armitage C J amp Conner M (1999b) Distinguishing perceptions of control from self-eYcacy

Predicting consumption of a low fat diet using the theory of planned behavior Journal of AppliedSocial Psychology 29 72ndash90


Armitage C J amp Conner M (1999c) Predictive validity of the theory of planned behaviour The roleof questionnaire format and social desirability Journal of Community and Applied Social Psychology 9261ndash272

Armitage C J amp Conner M (2000) Social cognition models and health behaviour A structuredreview Psychology and Health 15 173ndash189

Arnscheid R amp Schomers P (1996) Attitude and performance in groups A test of the theory ofplanned behavior on basketball players Zeitschrift fur Sozialpsychologie 27 61ndash69

Atsalakis M amp Sleap M (1996) Registration of children in a physical activity program Anapplication of the theory of planned behavior Ped iatric Exercise Science 8 166ndash176

Babrow A S Black D R amp TiVany S T (1990) Beliefs attitudes intentions and asmoking-cessation program A planned behavior analysis of communication campaign develop-ment Health Communication 2 145ndash163

Bagozzi R P (1992) The self-regulation of attitudes intentions and behavior Social PsychologyQuarterly 55 178ndash204

Bagozzi R P amp Kimmel S K (1995) A comparison of leading theories for the prediction ofgoal-directed behaviours British Journal of Social Psychology 34 437ndash461

Bakker A B Buunk B P amp Siero F W (1993) Condoomgebruik door heteroseksuelen Eenvergelijking van de theorie van gepland gedrag het health belief model en de protectie-motivatietheorie [Condom use among heterosexuals A comparison of the theory of planned behaviour thehealth belief model and protection motivation theory] Gedrag and Gezondheid Tijd schrift voor Psychologieand Gezondheid 21 238ndash254

Bamberg S (1995) When does the car-user change to the bus Problems and results of anapplication of the theory of planned behavior in the context of practical traYc planning Zeitschriftfur Sozialpsychologie 26 243ndash262

Bamberg S (1996) General or speci c attitudes in explaining ecological responsible behavior Anenlargement of the theory of planned behavior by the concept lsquoattitudes towards objectsrsquo Zeitschriftfur Sozialpsychologie 27 47ndash60

Bamberg S amp Ludemann C (1996) An empirical test of the theory of planned behavior in twochoice situations with two behavioral alternatives Bike versus car and container versus garbage canZeitschrift fur Sozialpsychologie 27 32ndash46

Bamberg S amp Schmidt P (1993) Choosing between means of transportationmdashan application ofthe theory of planned behavior Zeitschrift fur Sozialpsychologie 24 25ndash37

Bamberg S amp Schmidt P (1997) Theory-driven evaluation of an environmental policy measureUsing the theory of planned behavior Zeitschrift fur Sozialpsychologie 28 280ndash297

Bandura A (1986) Social foundations of thought and action Englewood CliVs NJ Prentice-HallBandura A (1992) On rectifying the comparative anatomy of perceived control Comments on

lsquoCognates of personal controlrsquo Applied and Preventive Psychology 1 121ndash126Bandura A (1997) Self-eYcacy The exercise of control New York W H Freeman amp CoBaron R M amp Kenny D A (1986) The moderatorndashmediator variable distinction in social

psychological research Conceptual strategic and statistical considerations Journal of Personality andSocial Psychology 51 1173ndash1182

Basen-Engquist K amp Parcel G S (1992) Attitudes norms and self-eYcacy A model ofadolescentsrsquo HIV-related sexual risk behavior Health Education Quarterly 19 263ndash277

Beale D A amp Manstead A S R (1991) Predicting mothersrsquo intentions to limit frequency ofinfantsrsquo sugar intake Testing the theory of planned behavior Journal of Applied Social Psychology 21409ndash431

Beck L amp Ajzen I (1991) Predicting dishonest actions using the theory of planned behaviorJournal of Research in Personality 25 285ndash301

Biddle S Goudas M amp Page A (1994) Social-psychological predictors of self-reported actual andintended physical activity in a university workforce sample British Journal of Sports Med icine 28160ndash163

Black D R amp Babrow A S (1991) Identi cation of campaign recruitment strategies for a steppedsmoking cessation intervention for a college campus Health Education Quarterly 18 235ndash247


Blue C L (1995) The predictive capacity of the theory of reasoned action and the theory of plannedbehavior in exercise research An integrated literature review Research in Nursing and Health 18105ndash121

Boissoneault E amp Godin G (1990) The prediction of intention to smoke only in designated worksite areas Journal of Occupational Med icine 32 621ndash624

Boldero J (1995) The prediction of household recycling of newspapers The role of attitudesintentions and situational factors Journal of Applied Social Psychology 25 440ndash462

Borgida E Conner C amp Manteufel L (1992) Understanding living kidney donation Abehavioural decision perspective In S Spacapan amp S Oskamp (Eds) Helping and being helped Naturalistic stud ies (pp 183ndash211) Newbury Park CA Sage

Borland R Owen N Hill D amp Scho eld P (1991) Predicting attempts and sustained cessationof smoking after the introduction of workplace smoking bans Health Psychology 10 336ndash342

Boudreau F Godin G Pineau R amp Bradet R (1995) Health risk appraisal in an occupationalsetting and its impact on exercise behavior Journal of Occupational and Environmental Med icine 371145ndash1150

Brubaker R G amp Fowler C (1990) Encouraging college males to perform testicular self-examination Evaluation of a persuasive message based on the revised theory of reasoned actionJournal of Applied Social Psychology 20 1411ndash1422

Brubaker R G amp Wickersham D (1990) Encouraging the practice of testicular self-examinationA eld application of the theory of reasoned action Health Psychology 9 154ndash163

Brug J Lechner L amp de Vries H (1995) Psychosocial determinants of fruit and vegetableconsumption Appetite 25 285ndash296

Burak L J (1994) Examination and prediction of elementary school teachersrsquo intentions to teachHIVAIDS education AIDS Education and Prevention 6 310ndash321

Carvajal S C Photiades J R Evans R I amp Nash S G (1997) Relating a social in uence modelto the role of acculturation in substance use among latino adolescents Journal of Applied SocialPsychology 27 1617ndash1628

Chan D-K amp Fishbein M (1993) Determinants of college womenrsquos intentions to tell theirpartners to use condoms Journal of Applied Social Psychology 23 1455ndash1470

Cialdini R B Kallgren C A amp Reno R R (1991) A focus theory of normative conduct Atheoretical re nement and reevaluation of the role of norms in human behavior In M P Zanna(Ed) Advances in experimental social psychology (Vol 24 pp 201ndash234) New York Academic Press

Cohen J (1977) Statistical power analysis for the behavioral sciences New York Academic PressCohen J (1992) A power primer Psychological Bulletin 112 155ndash159Collette M Godin G Bradet R amp Gionet N J (1994) Active living in communities

Understanding the intention to take up physical activity as an everyday way of life Canad ian Journalof Public Health 85 418ndash421

Conner M amp Armitage C J (1998) Extending the theory of planned behavior A review andavenues for further research Journal of Applied Social Psychology 28 1429ndash1464

Conner M amp Graham S (1994) Situational and attitudinal in uences upon studentsrsquo intentions touse condoms In H Schroder K Reschke M Johnston amp S Maes (Eds) Health psychology Potentialin d iversity (pp 91ndash100) Regensberg Verlag

Conner M Martin E Silverdale N amp Grogan S (1996) Dieting in adolescence An applicationof the theory of planned behaviour British Journal of Health Psychology 1 315ndash325

Conner M amp Norman P (1994) Comparing the health belief model and the theory of plannedbehaviour in health screening In D R Rutter amp L Quine (Eds) Social psychology and health Europeanperspectives (pp 1ndash24) Aldershot Avebury

Conner M amp Norman P (Eds) (1996a) Pred icting health behaviour Buckingham Open UniversityPress

Conner M amp Norman P (1996b) Body weight and shape control Examining componentbehaviours Appetite 27 135ndash150

Conner M amp Sherlock K (1994) Attitudes and ecstasy use Multid isciplinary Association for PsychedelicStud ies 4 18ndash19


Conner M amp Sparks P (1996) The theory of planned behaviour and health behaviours In MConner amp P Norman (Eds) Pred icting health behaviour (pp 121ndash162) Buckingham Open UniversityPress

Corby N H Schneider Jamner M amp Wolitski R J (1996) Using the theory of planned behaviorto predict intention to use condoms among male and female injecting drug users Journal of AppliedSocial Psychology 26 52ndash75

Courneya K S (1995) Understanding readiness for regular physical activity in older individuals Anapplication of the theory of planned behavior Health Psychology 14 80ndash87

Courneya K S amp Friedenreich C M (1997) Determinants of exercise during colorectal cancertreatment An application of the theory of planned behavior Oncology Nursing Forum 24 1715ndash1723

Courneya K S amp McAuley E (1994) Are there diVerent determinants of the frequency intensityand duration of physical activity Behavioral Med icine 20 84 90

Courneya K S amp McAuley E (1995) Cognitive mediators of the social in uencendashexerciseadherence relationship A test of the theory of planned behavior Journal of Behavioral Med icine 18499ndash515

Craig S Goldberg J amp Dietz W H (1996) Psychosocial correlates of physical activity among fthand eighth graders Preventive Med icine 25 506ndash513

Crawley F E (1990) Intentions of science teachers to use investigative teaching methods A test ofthe theory of planned behavior Journal of Research in Science Teaching 27 685ndash697

Crawley F E amp Black C B (1992) Causal modeling of secondary science studentsrsquo intentions toenrol in physics Journal of Research in Science Teaching 29 585ndash599

Crawley F E amp Koballa T R (1992) Hispanic-American studentsrsquo attitudes toward enrolling inhigh school chemistrymdasha study of planned behavior and belief-based change Hispanic Journal ofBehavioral Sciences 14 469ndash486

Crowne D amp Marlowe D (1964) The approval motive New York WileyDeBono K G amp Snyder M (1995) Acting on onersquos attitudes The role of history of choosing

situations Personality and Social Psychology Bulletin 21 629ndash636Dennison C M amp Shepherd R (1995) Adolescent food choice An application of the theory of

planned behaviour Journal of Human Nutrition and Dietetics 8 9ndash23Desroches J J-Y amp Chebat J-C (1995) Pourquoi les entrepreneurs quebecois vont sur le marche

boursier Attitudes et facteurs de decision [Why Quebec businesses go public Attitudes and thedecision-making process] Revue Canad ienne d es Sciences d e lrsquoAdministration 12 27ndash37

Deutsch M amp Gerard H B (1955) A study of normative and informational social in uences uponindividual judgment Journal of Abnormal and Social Psychology 51 629ndash636

de Vellis B M Blalock S J amp Sandler R S (1990) Predicting participation in cancer screeningThe role of perceived behavioral control Journal of Applied Social Psychology 20 639ndash660

de Vries H Backbier E Kok G amp Dijkstra M (1995) The impact of social in uences in thecontext of attitude self-eYcacy intention and previous behavior as predictors of smoking onsetJournal of Applied Social Psychology 25 237ndash257

de Vries H Dijkstra M amp Kuhlman P (1988) Self-eYcacy The third factor besides attitude andsubjective norm as a predictor of behavioural intentions Health Education Research 3 273ndash282

Dilorio C (1997) Neuroscience nursesrsquo intentions to care for persons with HIVAIDS Journal ofNeuroscience Nursing 29 50ndash55

Doll J amp Ajzen I (1992) Accessibility and stability of predictors in the theory of planned behaviorJournal of Personality and Social Psychology 63 754ndash765

Doll J Mentz M amp Orth B (1991) Zur vorhersage zielgerichteten handelns Einstellungsubjektive handlungskompetenz und emotionen [The production of goal-directed behaviourAttitude subjective estimations of competence and emotions] Zeitschrift fur Experimentelle undAngewand te Psychologie 38 539ndash559

Dzewaltowski D A Noble J M amp Shaw J M (1990) Physical activity participationmdashsocialcognitive theory versus the theories of reasoned action and planned behavior Journal of Sport andExercise Psychology 12 388ndash405

East R (1993) Investment decisions and the theory of planned behaviour Journal of EconomicPsychology 14 337ndash375


East R (1996) Redress seeking as planned behavior Journal of Consumer Satisfaction Dissatisfaction andComplaining Behavior 9 27ndash34

Fishbein M (1980) A theory of reasoned action Some applications and implications In H E HoweJr amp M M Page (Eds) Nebraska symposium on motivation (Vol 27 pp 65ndash116) Lincoln Universityof Nebraska Press

Fishbein M amp Ajzen I (1975) Belief attitude intention and behavior An introduction to theory and researchReading MA Addison-Wesley

Fishbein M amp Stasson M (1990) The role of desires self-predictions and perceived control in theprediction of training session attendance Journal of Applied Social Psychology 20 173ndash198

Flynn B S Dana G S Goldstein A O Bauman K E Cohen J E Gottlieb N H SolomonL J amp Munger M C (1997) State legislatorsrsquo intentions to vote and subsequent votes on tobaccocontrol legislation Health Psychology 16 401ndash404

Gaes G G Kalle R J amp Tedeschi J I (1978) Impression management in the forced compliancesituation Two studies using the bogus pipeline Journal of Experimental Social Psychology 9 491ndash501

Gatch C L amp Kendzierski D (1990) Predicting exercise intentions The theory of plannedbehavior Research Quarterly for Exercise and Sport 61 100ndash102

Giles M amp Cairns E (1995) Blood donation and Ajzenrsquos theory of planned behaviour Anexamination of perceived behavioural control British Journal of Social Psychology 34 173ndash188

Godin G (1993) The theories of reasoned action and planned behavior Overview of ndingsemerging research problems and usefulness for exercise promotion Journal of Applied Sport Psychology5 141ndash157

Godin G (1996) Le non-usage du tabac (Non-use of tobacco) Alcoologie 18 237ndash242Godin G Fortin C Mahnes G Boyer R Nadeau D Duval B Bradet R amp Hounsa A (1993)

University studentsrsquo intention to seek medical care promptly if symptoms of sexually transmitteddiseases were suspected Sexually Transmitted Diseases 20 100ndash104

Godin G Fortin C Michaud F Bradet R amp Kok G (1997) Use of condoms Intention andbehaviour of adolescents living in juvenile rehabilitation centres Health Education Research 12289ndash300

Godin G amp Gionet N J (1991) Determinants of an intention to exercise of an electric powercommissionrsquos employees Ergonomics 34 1221ndash1230

Godin G amp Kok G (1996) The theory of planned behavior A review of its applications tohealth-related behaviors American Journal of Health Promotion 11 87ndash98

Godin G amp Lepage L (1988) Understanding the intentions of pregnant nullipara to not smokecigarettes after child birth Journal of Drug Education 18 115ndash124

Godin G Maticka-Tyndale E Adrien A Manson-Singer S Willms D amp Cappon P (1996)Cross-cultural testing of three social cognitive theories An application to condom use Journal ofApplied Social Psychology 26 1556ndash1586

Godin G Savard J Kok G Fortin C amp Boyer R (1996) HIV seropositive gay menUnderstanding adoption of safe sexual practices AIDS Education and Prevention 8 529ndash545

Godin G Valois P Jobin J amp Ross A (1991) Prediction of intention to exercise of individualswho have suVered from coronary heart disease Journal of Clinical Psychology 47 762ndash772

Godin G Valois P amp Lepage L (1993) The pattern of in uence of perceived behavioral controlupon exercising behaviormdashan application of Ajzenrsquos theory of planned behavior Journal ofBehavioral Med icine 16 81ndash102

Godin G Valois P Lepage L amp Desharnais R (1992) Predictors of smoking behaviourmdashanapplication of Ajzenrsquos theory of planned behaviour British Journal of Add iction 87 1335ndash1343

Godin G Vezina L amp Leclerc O (1989) Factors in uencing intentions of pregnant women toexercise after giving birth Public Health Reports 104 188ndash195

Greenwald A G (1975) Consequences of prejudice against the null hypothesis Psychological Bulletin82 1ndash20

Gummeson L Jonsson I amp Conner M (1997) Predicting intentions and behaviour of Swedish10ndash16-year olds at breakfast Food Quality and Preference 8 297ndash306

Hamid P N amp Cheng S-T (1995) Predicting antipollution behavior The role of molar behavioralintentions past behavior and locus of control Environment and Behavior 27 679ndash698


Haney J J Czerniak C M amp Lumpe A T (1996) Teacher beliefs and intentions regarding theimplementation of science education reform strands Journal of Research in Science Teaching 33971ndash993

Hanson M J S (1997) The theory of planned behavior applied to cigarette smoking inAfrican-American Puerto Rican and non-Hispanic white teenage females Nursing Research 46155ndash162

Harrison D A (1995) Volunteer motivation and attendance decisions Competitive theory testingin multiple samples from a homeless shelter Journal of Applied Psychology 80 371ndash385

Hausenblas H A Carron A V amp Mack D E (1997) Application of the theories of reasonedaction and planned behavior to exercise behavior A meta-analysis Journal of Sport and ExercisePsychology 19 36ndash51

Hedges L V amp Olkin I (1985) Statistical methods for meta-analysis San Diego CA Academic PressHessing D J ElVers H amp Weigel R H (1988) Exploring the limits of self-reports and reasoned

action An investigation of the psychology of tax evasion behavior Journal of Personality and SocialPsychology 54 405ndash413

Hill M Mann L amp Wearing A J (1996) The eVects of attitude subjective norm and self-eYcacyon intention to benchmark A comparison between managers with experience and no experience inbenchmarking Journal of Organizational Behavior 17 313ndash327

Hillhouse J J Adler C M Drinnon J amp Turrist R (1997) Application of Ajzenrsquos theory ofplanned behavior to predict sunbathing tanning salon use and sunscreen use intentions andbehaviors Journal of Behavioral Med icine 20 365ndash378

Hinsz V B amp Nelson L C (1990) Testing models of turnover intentions with university facultyJournal of Applied Social Psychology 20 68ndash84

Hogg M A amp Abrams D (1988) Social id enti cations A social psychology of intergroup relations and groupprocesses London Routledge

Horne T E (1994) Predictors of physical activity intentions and behavior for rural homemakersCanad ian Journal of Public Health 85 132ndash135

Hounsa A M Godin G Alihonou E amp Valois P (1993) An application of Ajzenrsquos theory ofplanned behaviour to predict mothersrsquo intention to use oral rehydration therapy in a rural area ofBenin Social Science and Med icine 37 253ndash261

Jemmott J B Jemmott L S amp Hacker C I (1992) Predicting intentions to use condoms amongAfrican-American adolescents The theory of planned behavior as a model of HIV risk-associatedbehavior Ethnicity and Disease 2 371ndash380

Jonas K amp Doll J (1996) A critical evaluation of the theory of reasoned action and the theory ofplanned behavior Zeitschrift fur Sozialpsychologie 27 18ndash31

Kelly C amp Breinlinger S (1995) Attitudes intentions and behavior A study of womenrsquosparticipation in collective action Journal of Applied Social Psychology 25 1431ndash1446

Kimiecik J (1992) Predicting vigorous physical activity of corporate employees Comparing thetheories of reasoned action and planned behavior Journal of Sport and Exercise Psychology 14 192ndash206

Kinket B Paans L amp Verplanken B (1992) Patient education by general practitionersApplication of the theory of planned behavior Gedrag and Gezondheid Tijd schrift voor Psychologie andGezondheid 20 187ndash195

Klobas J E (1995) Beyond information quality Fitness for purpose and electronic informationresource use Journal of Information Science 21 95ndash114

Kolvereid L (1996) Prediction of employment status choice intentions Entrepreneurship Theory andPractice 21 47ndash57

Kurland N B (1995) Ethical intentions and the theories of reasoned action and planned behaviorJournal of Applied Social Psychology 25 297ndash313

Kurland N B (1996) Sales agents and clients Ethics incentives and a modi ed theory of plannedbehavior Human Relations 49 51ndash74

Langer E J (1975) The illusion of control Journal of Personality and Social Psychology 32 311ndash328Lavoie M amp Godin G (1991) Correlates of intention to use condoms among auto mechanic

students Health Education Research 6 313ndash316


Lay C H amp Burns P (1991) Intentions and behavior in studying for an examination The role oftrait procrastination and its interaction with optimism Journal of Social Behavior and Personality 6605ndash617

Lechner L amp de Vries H (1995) Starting participation in an employee tness program Attitudessocial in uence and self-eYcacy Preventive Med icine 24 627ndash633

Lerner M J (1977) The justice motive Some hypotheses as to its origins and forms Journal ofPersonality 45 1ndash52

Lloyd H M Paisley C M amp Mela D J (1993) Changing to a low fat diet Attitudes and beliefsof UK consumers European Journal of Clinical Nutrition 47 361ndash373

McCaul K D OrsquoNeill H K amp Glasgow R E (1988) Predicting the performance of dentalhygiene behaviors An examination of the Fishbein and Ajzen model and self-eYcacy expectationsJournal of Applied Social Psychology 18 114ndash128

McCaul K D Sandgren A K OrsquoNeill H K amp Hinsz V B (1993) The value of the theory ofplanned behavior perceived control and self-eYcacy expectations for predicting health-protectivebehaviors Basic and Applied Social Psychology 14 231ndash252

Madden T J Ellen P S amp Ajzen I (1992) A comparison of the theory of planned behavior andthe theory of reasoned action Personality and Social Psychology Bulletin 18 3ndash9

Maher R A amp Rickwood D (1997) The theory of planned behavior domain speci c self-eYcacyand adolescent smoking Journal of Child and Substance Abuse 6 57ndash76

Manstead A S R amp Parker D (1995) Evaluating and extending the theory of planned behaviourIn W Stroebe amp M Hewstone (Eds) European Review of Social Psychology (Vol 6 pp 69ndash95)Chichester Wiley

Manstead A S R amp van Eekelen S A M (1998) Distinguishing between perceived behavioralcontrol and self-eYcacy in the domain of academic achievement intentions and behavior Journal ofApplied Social Psychology 28 1375ndash1392

Marcoux B C amp Shope J T (1997) Application of the theory of planned behavior to adolescentuse and misuse of alcohol Health Education Research 12 323ndash331

Mathieson K (1991) Predicting user intentions Comparing the technology acceptance model withthe theory of planned behavior Information Systems Research 2 173ndash191

Millstein S G (1996) Utility of the theories of reasoned action and planned behavior for predictingphysician behavior A prospective analysis Health Psychology 15 398ndash402

Montano D E amp Taplin S H (1991) A test of an expanded theory of reasoned action to predictmammography participation Social Science and Med icine 32 733ndash741

Morojele N K amp Stephenson G M (1994) Addictive behaviours Predictors of abstinenceintentions and expectations in the theory of planned behaviour In D R Rutter amp L Quine (Eds)Social psychology and health European perspectives (pp 47ndash70) Aldershot Avebury

Morrison D M Rogers-Gillmore M amp Baker S A (1995) Determinants of condom use amonghigh-risk heterosexual adults A test of the theory of reasoned action Journal of Applied SocialPsychology 25 651ndash676

Mullen B (1989) Advanced BASIC meta-analysis Hillsdale NJ ErlbaumMurphy W G amp Brubaker R G (1990) EVects of a brief theory-based intervention on the

practice of testicular self-examination by high school males Journal of School Health 60 459ndash462Nash R Edwards H amp Nebauer M (1993) EVects of attitudes subjective norms and perceived

control on nursesrsquo intention to assess patientsrsquo pain Journal of Advanced Nursing 18 941ndash947Netemeyer R G Andrews J C amp Durvasula S (1993) A comparison of three behavioral

intention models The case of Valentinersquos day gift-giving Advances in Consumer Research 20 135ndash141Netemeyer R G amp Burton S (1990) Examining the relationship between voting behavior

intention perceived behavioral control and expectation Journal of Applied Social Psychology 20661ndash680

Netemeyer R G Burton S amp Johnston M (1991) A comparison of two models for the predictionof volitional and goal-directed behaviors A con rmatory analysis approach Social PsychologyQuarterly 54 87ndash100

Nguyen M N Otis J amp Potvin L (1996) Determinants of intention to adopt a low-fat diet inmen 30 to 60 years old Implications for heart health promotions American Journal of HealthPromotion 10 201ndash207


Nguyen M N Potvin L amp Otis J (1997) Regular exercise in 30- to 60-year-old men Combiningthe stages-of-change model and the theory of planned behaviour to identify determinants fortargeting heart health interventions Journal of Community Health 22 233ndash246

Norman P amp Bonnett C (1995) Managersrsquo intentions to be assessed for national vocationalquali cations An application of the theory of planned behavior Social Behavior and Personality 2359ndash68

Norman P amp Conner M (1996) Predicting health-check attendance among prior attenders andnon-attenders The role of prior behavior in the theory of planned behavior Journal of Applied SocialPsychology 26 1010ndash1026

Norman P amp Smith L (1995) The theory of planned behaviour and exercise An investigation intothe role of prior behaviour behavioural intentions and attitude variability European Journal of SocialPsychology 25 403ndash415

Norwich B amp Duncan J (1990) Attitudes subjective norm perceived preventive factorsintentions and learning science Testing a modi ed theory of reasoned action British Journal ofEducational Psychology 60 312ndash321

Norwich B amp Rovoli I (1993) AVective factors and learning behaviour in secondary schoolmathematics and English lessons for average and low attainers British Journal of EducationalPsychology 63 308ndash321

Nucifora J Gallois C amp Kashima Y (1993) In uences on condom use among undergraduatesTesting the theories of reasoned action and planned behaviour In D J Terry C Gallois amp MMcCamish (Eds) The theory of reasoned action Its application to AIDS-preventive behaviour (pp 47ndash64)Oxford Pergamon

Nunnally J C (1978) Psychometric theory New York McGraw-HillOrsquoCallaghan F V Chant D C Callan V J amp Baglioni A (1997) Modes of alcohol use by young

adults An examination of various attitude-behavior theories Journal of Stud ies of Alcohol 58502ndash507

Olson J M amp Zanna M P (1993) Attitudes and attitude change Annual Review of Psychology 44117ndash154

Orbell S Hodgkins S amp Sheeran P (1997) Implementation intentions and the theory of plannedbehavior Personality and Social Psychology Bulletin 23 945ndash954

Oslashygard L amp Rise J (1996) Predicting the intention to eat healthier food among young adultsHealth Education Research 11 453ndash461

Parker D Manstead A S R amp Stradling S G (1995) Extending the theory of planned behaviourThe role of personal norm British Journal of Social Psychology 34 127ndash137

Parker D Manstead A S R Stradling S G Reason J T amp Baxter J S (1992) Intention tocommit driving violationsmdashan application of the theory of planned behavior Journal of AppliedPsychology 77 94ndash101

Pellino T A (1997) Relationships between patient attitudes subjective norms perceived controland analgesic use following elective orthopedic surgery Research in Nursing and Health 20 97ndash105

Plies K amp Schmidt P (1996) Intention = behavior A representative panel-study to test the theoryof planned behavior in the context of AIDS prevention Zeitschrift fur Sozialpyschologie 27 70ndash80

Prislin R (1993) EVect of direct experience on the relative importance of attitudes subjectivenorms and perceived behavioral control for the prediction of intentions and behavior Psychology 3051ndash58

Prislin R amp Kovrlija N (1992) Predicting behavior of high and low self-monitorsmdashan applicationof the theory of planned behavior Psychological Reports 70 1131ndash1138

Quine L amp Rubin R (1997) Attitude subjective norm and perceived behavioural control aspredictors of womenrsquos intentions to take hormone replacement therapy British Journal of HealthPsychology 2 199ndash216

Raats M M Shepherd R amp Sparks P (1995) Including moral dimensions of choice within thestructure of the theory of planned behavior Journal of Applied Social Psychology 25 484ndash494

Randall D M amp Gibson A M (1991) Ethical decision making in the medical professionmdashanapplication of the theory of planned behavior Journal of Business Ethics 10 111ndash122

Randall D M amp WolV J A (1994) The time interval in the intentionndashbehaviour relationshipMeta-analysis British Journal of Social Psychology 33 405ndash418


Rannie K amp Craig D M (1997) Adolescent femalesrsquo attitudes subjective norms perceivedbehavioral control and intentions to use latex condoms Public Health Nursing 14 51ndash57

Reinecke J Schmidt P amp Ajzen I (1996) Application of the theory of planned behavior toadolescentsrsquo condom use A panel study Journal of Applied Social Psychology 26 749ndash772

Richard L Dedobbeleer N Champagne F amp Potvin L (1994) Predicting child restraint deviceuse A comparison of two models Journal of Applied Social Psychology 24 1837ndash1847

Richard R van der Pligt J amp de Vries N (1995) Anticipated aVective reactions and preventionof AIDS British Journal of Social Psychology 34 9ndash21

Richard R van der Pligt J amp de Vries N (1996) Anticipated aVect and behavioral choice Basicand Applied Social Psychology 18 111ndash129

Richardson H R L Beazley R P Delaney M E amp Langille D B (1997) Factors in uencingcondom use among students attending high school in Nova Scotia The Canad ian Journal of HumanSexuality 6 185ndash196

Rosenthal R (1979) The lsquo le drawer problemrsquo and tolerance for null results Psychological Bulletin 86638ndash641

Rosenthal R (1984) Meta-analytic procedures for social research Beverly Hill CA SageSahni A (1994) Incorporating perceptions of nancial control in purchase prediction An empirical

examination of the theory of planned behavior Advances in Consumer Research 21 442ndash448Schaalma H Kok G amp Peters L (1993) Determinants of consistent condom use by adolescents

The impact of experience of sexual intercourse Health Education Research 8 255ndash269Schifter D B amp Ajzen I (1985) Intention perceived control and weight loss An application of

the theory of planned behavior Journal of Personality and Social Psychology 49 843ndash851Schlegel R P DrsquoAvernas J R Zanna M P DeCourville N H amp Manske S R (1992) Problem

drinking A problem for the theory of reasoned action Journal of Applied Social Psychology 22358ndash385

Sheeran P amp Orbell S (1998) Do intentions predict condom use Meta-analysis and examinationof six moderator variables British Journal of Social Psychology 37 231ndash250

Shepperd B H Hartwick J amp Warshaw P R (1988) The theory of reasoned action Ameta-analysis of past research with recommendations for modi cations and future research Journalof Consumer Research 15 325ndash343

Sparks P (1994) Attitudes towards food Applying assessing and extending the lsquotheory of plannedbehaviourrsquo In D R Rutter amp L Quine (Eds) Social psychology and health European perspectives(pp 25ndash46) Aldershot Avebury Press

Sparks P Guthrie C A amp Shepherd R (1997) The dimensional structure of the lsquoperceivedbehavioral controlrsquo construct Journal of Applied Psychology 27 418ndash438

Sparks P Hedderley D amp Shepherd R (1992) An investigation into the relationship betweenperceived control attitude variability and the consumption of two common foods European Journalof Social Psychology 22 55ndash71

Sparks P amp Shepherd R (1992) Self-identity and the theory of planned behaviormdashassessing therole of identi cation with green consumerism Social Psychology Quarterly 55 388ndash399

Sparks P Shepherd R amp Frewer L J (1995) Assessing and structuring attitudes toward the useof gene technology in food production The role of perceived ethical obligation Basic and AppliedSocial Psychology 16 267ndash285

Sparks P Shepherd R Wieringa N amp Zimmermans N (1995) Perceived behavioural controlunrealistic optimism and dietary change An exploratory study Appetite 24 243ndash255

Sutton S (1994) The past predicts the future Interpreting behaviourndashbehaviour relationships insocial psychological models of health behaviour In D R Rutter amp L Quine (Eds) Social psychologyand health European perspectives (pp 71ndash88) Aldershot Avebury

Sutton S (1998) Explaining and predicting intentions and behavior How well are we doing Journalof Applied Social Psychology 28 1318ndash1339

Taylor S amp Todd P (1995) An integrated model of waste management behavior A test ofhousehold recycling and composting intentions Environment and Behavior 27 603ndash630

Tedesco L A KeVer M A amp Fleck-Kandath C (1991) Self-eYcacy reasoned action and oralhealth behavior reports A social cognitive approach to compliance Journal of Behavioral Med icine 14341ndash355


Terry D J (1993) Self-eYcacy expectancies and the theory of reasoned action In D J Terry CGallois amp M McCamish (Eds) The theory of reasoned action Its application to AIDs-preventive behaviour(pp 135ndash151) Oxford Pergamon

Terry D J amp Hogg M A (1996) Group norms and the attitudendashbehavior relationship A role forgroup identi cation Personality and Social Psychology Bulletin 22 776ndash793

Terry D J Hogg M A amp White K M (1999) The theory of planned behaviour Self-identitysocial identity and group norms British Journal of Social Psychology 38 225ndash244

Terry D J Hogg M A White K M (2000) Attitudendashbehavior relations Social identity and groupmembership In D J Terry amp M A Hogg (Eds) Attitudes behavior and social context The role of normsand group membership (pp 67ndash93) London Erlbaum

Terry D J amp OrsquoLeary J E (1995) The theory of planned behaviour The eVects of perceivedbehavioural control and self-eYcacy British Journal of Social Psychology 34 199ndash220

Theodorakis Y (1992) Prediction of athletic participationmdasha test of planned behavior theoryPerceptual and Motor Skills 74 371ndash379

Theodorakis Y (1994) Planned behavior attitude strength role identity and the prediction ofexercise behavior The Sport Psychologist 8 149ndash165

Theodorakis Y Bagiatis K amp Goudas M (1995) Attitudes toward teaching individuals withdisabilities Application of planned behavior theory Adapted Physical Activity Quarterly 12 151ndash160

Tolman R M Edleson J L amp Fendrich M (1996) The applicability of the theory of plannedbehavior to abusive menrsquos cessation of violent behavior Violence and Victims 11 341ndash354

Towler G amp Shepherd R (1991) Modi cation of Fishbein and Ajzenrsquos theory of reasoned actionto predict chip consumption Food Quality and Preference 3 37ndash45

Traelign B amp Nordlund S (1993) Visiting public drinking places in Oslo An application of the theoryof planned behaviour Add iction 88 1215ndash1224

Tra mow D amp Finlay K A (1996) The importance of subjective norms for a minority of peopleBetween subjects and within-subjects analyses Personality and Social Psychology Bulletin 22 820ndash828

Turner J C (1985) Social categorization and the self-concept A social cognitive theory of groupbehaviour In E J Lawler (Ed) Advances in group process Theory and research (Vol 2 pp 77ndash122)Greenwich CT JAI Press

Van den Putte B (1991) 20 years of the theory of reasoned action of Fishbein and Ajzen A meta-analysisUnpublished manuscript University of Amsterdam

Van Ryn M Lytle L A amp Kirscht J P (1996) A test of the theory of planned behavior for twohealth-related practices Journal of Applied Social Psychology 26 871ndash883

Van Ryn M amp Vinokur A D (1992) How did it work An examination of the mechanismsthrough which an intervention for the unemployed promoted job-search behavior American Journalof Community Psychology 20 577ndash597

Vermette L amp Godin G (1996) Nursesrsquo intentions to provide home care The impact of AIDS andhomosexuality AIDS Care 8 479ndash488

Wambach K A (1997) Breastfeeding intention and outcome A test of the theory of plannedbehavior Research in Nursing and Health 20 51ndash59

Wankel L M amp Mummery W K (1993) Using national survey data incorporating the theory ofplanned behavior Implications for social marketing strategies in physical activity Journal of AppliedSport Psychology 5 158ndash177

Warshaw P R amp Davis F D (1985) Disentangling behavioral intentions and behavioralexpectations Journal of Experimental Social Psychology 21 213ndash228

White K M Terry D J amp Hogg M A (1994) Safer sex behavior The role of attitudes normsand control factors Journal of Applied Social Psychology 24 2164ndash2192

White K R (1982) The relation between socio-economic status and academic achievementPsychological Bulletin 91 461ndash481

Wicker A W (1969) Attitudes versus actions The relationship of verbal and overt behavioralresponses to attitude objects Journal of Social Issues 25 41ndash47

Wiesner M amp Tesch-Romer C (1996) Use of hearing aids by the elderly Correlation betweenintention and behavior Zeitschrift fur Gerontologie und Geriatrie 29 273ndash279


Willemson M C de Vries H van Breukelen G amp Oldenburg B (1996) Determinants ofintention to quit smoking among Dutch employees The in uence of social environment PreventiveMed icine 25 195ndash202

Wilson D Zenda A McMaster J amp Lavelle S (1992) Factors predicting Zimbabwean studentsrsquointention to use condoms Psychology and Health 7 99ndash114

Yordy G A amp Lent R W (1993) Predicting aerobic exercise participationmdashsocial cognitivereasoned action and planned behavior models Journal of Sport and Exercise Psychology 15 363ndash374

Received 20 January 1998 revised version received 25 February 2000

Appendix

Coding of volition was based on participantsrsquo mean PBC responses (ie the degree to which they ratedbehaviours as controllable or uncontrollable) Mean values of PBC (including self-eYcacy andlsquoperceived control over behaviourrsquo) measures were taken from all papers where the appropriatestatistics were reported or obtained From these 62 studies the mean scores were transformed to acommon metric (unipolar + 1 (low control) to + 7 (high control) scales) Across all these studies themean value of control was 496 (SD = 102) meaning that participants generally reportedperceiving control over the behaviours in question These data were subjected to two forms ofanalyses First a categorical lsquovolitionrsquo variable was created based on a mean split This discriminatedbehaviours that were rated as being relatively volitional from those rated as being less volitional Theseanalyses revealed thatmdashunder conditions of greater volitional controlmdashPBC accounted for more ofthe variance ( + 3 behaviour + 8 intention over and above TRA variables) than under conditionsof less volitional control ( + 2 behaviour + 5 intention)

Secondly mean PBC scores were plotted against proportion of variance contributed (to eitherintention or behaviour) by PBC The latter analyses allowed us to control for the fact that participantsgenerally report control over behaviour This resulted in a correlation of 05 between mean PBC ratingand the proportion of additional variance in intention explained by PBC The equivalent correlationfor behaviour was r = 16 Whilst the correlation of 05 should be regarded as lsquotrivialrsquo (see Cohen1992) the correlation for behaviour is suggestive of the fact that lower volitional control is associatedwith a greater impact of PBC on behaviour Note that this nding contradicts the results of the rstanalyses

A third form of analysis analysed responses above and below the mid-point (ie 4) of thestandardized PBC scale This produced only eight studies with PBC scores below the mid-point forthe prediction of intention and four studies below the mid-point for the prediction of behaviourThese yielded data that failed to exceed Rosenthalrsquos (1984) tolerance level (ie only two further studieswould have been required to overturn the ndings) and these are not presented

Overall in attempting to code for lsquovolitionrsquo we found contradictory results and can onlyconcludemdashin line with the Introductionmdashthat experimental studies or studies that appropriatelymeasure volitional variables might be the only way to untangle such an issue One possibility is thatlsquoperceived control over behaviourrsquo might actually tap the extent to which individuals believe that abehaviour is within their volitional control This might explain why lsquoperceived control over behaviourrsquohas rarely directly contributed to the prediction of intention or behaviour (see Armitage amp Conner1999a 1999b)


Ajzen (eg 1991) extended the TRA to include a measure of perceivedbehavioural controlmdasha variable that had received a great deal of attention in socialcognition models designed to predict health behaviours (eg health belief modelprotection motivation theory see Armitage amp Conner 2000 Conner amp Norman1996a) Perceived behavioural control (PBC) is held to in uence both intention andbehaviour (see Fig 1) The rationale behind the addition of PBC was that it wouldallow prediction of behaviours that were not under complete volitional controlThus while the TRA could adequately predict behaviours that were relativelystraightforward (ie under volitional control) under circumstances where therewere constraints on action the mere formation of an intention was insuYcient topredict behaviour The inclusion of PBC provides information about the potentialconstraints on action as perceived by the actor and is held to explain whyintentions do not always predict behaviour1

With respect to the in uence of PBC on intention Ajzen (1991 p 188) statesthat lsquoThe relative importance of attitude subjective norm and perceivedbehavioral control in the prediction of intention is expected to vary acrossbehaviors and situationsrsquo That is in situations where (for example) attitudes arestrong or where normative in uences are powerful PBC may be less predictive ofintentions Thus Ajzen (1991) argues that the magnitude of the PBCndashintentionrelationship is dependent upon the type of behaviour and the nature of thesituation Indirect evidence for this claim has been demonstrated in studies thathave shown that measures of attitude strength (eg Sparks Hedderley amp Shepherd1992) and individual diVerences in sociability (eg Tra mow amp Finlay 1996)increase the relative predictive power of attitudes and subjective norms respect-ively In general individuals are more disposed (ie intend) to engage in behavioursthat are believed to be achievable (cf Bandura 1997)

PBC is also held to exert both direct and interactive (with behavioural intentions)eVects on behaviour This is based on the following rationale that however stronglyheld the implementation of an intention into action is at least partially determinedby personal and environmental barriers thus lsquoThe addition of perceived behav-ioural control should become increasingly useful as volitional control over behaviordecreasesrsquo (Ajzen 1991 p 185) Therefore in situations where prediction of1The authors wish to thank Russell Spears for his helpful comments with respect to the following section

Figure 1 The theory of planned behaviour


















Self-report





Control












Subjective norms


Aims





Method















Analyses









Results

Overall nd ings

























Control





varianceadded by

PBC






Subjective norms




addedb








Discussion


Overall nd ings























Subjective norms






Conclusions


References





































































































































































































































Appendix






















Self-report





Control












Subjective norms


Aims





Method















Analyses









Results

Overall nd ings

























Control





varianceadded by

PBC






Subjective norms




addedb








Discussion


Overall nd ings























Subjective norms






Conclusions


References





































































































































































































































Appendix








Control












Subjective norms


Aims





Method















Analyses









Results

Overall nd ings

























Control





varianceadded by

PBC






Subjective norms




addedb








Discussion


Overall nd ings























Subjective norms






Conclusions


References





































































































































































































































Appendix













Subjective norms


Aims





Method















Analyses









Results

Overall nd ings

























Control





varianceadded by

PBC






Subjective norms




addedb








Discussion


Overall nd ings























Subjective norms






Conclusions


References





































































































































































































































Appendix







Method















Analyses









Results

Overall nd ings

























Control





varianceadded by

PBC






Subjective norms




addedb








Discussion


Overall nd ings























Subjective norms






Conclusions


References





































































































































































































































Appendix









Analyses









Results

Overall nd ings

























Control





varianceadded by

PBC






Subjective norms




addedb








Discussion


Overall nd ings























Subjective norms






Conclusions


References





































































































































































































































Appendix







Results

Overall nd ings

























Control





varianceadded by

PBC






Subjective norms




addedb








Discussion


Overall nd ings























Subjective norms






Conclusions


References





































































































































































































































Appendix























Control





varianceadded by

PBC






Subjective norms




addedb








Discussion


Overall nd ings























Subjective norms






Conclusions


References





































































































































































































































Appendix








Subjective norms




addedb








Discussion


Overall nd ings























Subjective norms






Conclusions


References





































































































































































































































Appendix








Discussion


Overall nd ings























Subjective norms






Conclusions


References





































































































































































































































Appendix






















Subjective norms






Conclusions


References





































































































































































































































Appendix







Conclusions


References





































































































































































































































Appendix

































































































































































































































Appendix






Armitage Efficacy of the Theory of Planned Behavior

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Transcript of Armitage Efficacy of the Theory of Planned Behavior