QuestionsQuestions

In a correlation research paper do the authors note In a correlation research paper do the authors note the predictive variable and the criterion variable?the predictive variable and the criterion variable?

Is it common to combine different research Is it common to combine different research strategies in a single experiment?strategies in a single experiment?

Do researchers sometimes make larger scales for Do researchers sometimes make larger scales for rating scale questions to produce a larger range of rating scale questions to produce a larger range of responses in order to attempt to avoid the scale responses in order to attempt to avoid the scale being reduced?being reduced?

Does the type of survey determine what type of Does the type of survey determine what type of question to ask, or is one question better to use question to ask, or is one question better to use than another?than another?

More QuestionsMore Questions

How valid are correlational studies when How valid are correlational studies when there is always a directionality and third-there is always a directionality and third-variable problem that can affect the results?variable problem that can affect the results?

In what sub-field(s) of psychology are case In what sub-field(s) of psychology are case study designs most likely to be used?study designs most likely to be used?

For the exercises from Ch11 on factorial For the exercises from Ch11 on factorial designs, I was confused on how to look at a designs, I was confused on how to look at a chart/table or a graph and see if there is an chart/table or a graph and see if there is an interaction. Problems #8 and #9 were very interaction. Problems #8 and #9 were very confusing for me. confusing for me.

Exam conceptsExam concepts

Experiment, third-variable problem, Experiment, third-variable problem, directionality problem, manipulation and directionality problem, manipulation and control of variables, treatment conditions, control of variables, treatment conditions, levels, ways of controlling extraneous levels, ways of controlling extraneous variables (holding constant, matching and variables (holding constant, matching and randomization), experimental and control randomization), experimental and control groups (no-treatment, placebo), simulation groups (no-treatment, placebo), simulation and field studiesand field studies

Exam conceptsExam concepts

between-subjects design (what it is, major between-subjects design (what it is, major adv and disadv), at least two examples of adv and disadv), at least two examples of threats to internal validity of btw-subjects threats to internal validity of btw-subjects designsdesigns

Within-subjects designs (what it is, major Within-subjects designs (what it is, major adv and disadv - time-related, order), adv and disadv - time-related, order), dealing with time-related threads and order dealing with time-related threads and order effects, matched-subjects designs effects, matched-subjects designs (controlling time and counterbalancing)(controlling time and counterbalancing)

Exam conceptsExam concepts

Distinction btw nonexperimental and quasi-Distinction btw nonexperimental and quasi-experimental research strategy, experimental research strategy, nonequivalent group (general understanding nonequivalent group (general understanding and one example of design), pre-post and one example of design), pre-post designs (general understanding and one designs (general understanding and one example of design), developmental research example of design), developmental research designs (cross-sectional and longitudinal – designs (cross-sectional and longitudinal – differences), cohort effectsdifferences), cohort effects

Exam conceptsExam concepts

Factor, factorial design, main effect, interaction, Factor, factorial design, main effect, interaction, between and within-subjects factorial designs between and within-subjects factorial designs (calculating number of participants and (calculating number of participants and deciphering the notation e.g. 2x3x2), mixed deciphering the notation e.g. 2x3x2), mixed designsdesigns

Types of designs under descriptive research Types of designs under descriptive research strategy (observational, survey, case study), types strategy (observational, survey, case study), types of observation, types of questions, correlation, of observation, types of questions, correlation, positive and negative correlation, predictor and positive and negative correlation, predictor and criterion variable, applications of correlations and criterion variable, applications of correlations and problems problems

Exam conceptsExam concepts

Differences between case study and single-Differences between case study and single-case design, baseline phase, treatment case design, baseline phase, treatment phase, visual inspection of data, provide phase, visual inspection of data, provide example of one specific type of a single-example of one specific type of a single-subject design (e.g. ABAB), general adv and subject design (e.g. ABAB), general adv and disadv of single-subject designsdisadv of single-subject designs

Single-Subject Research DesignsSingle-Subject Research Designs

Chapter 13Chapter 13

Dusana RybarovaDusana RybarovaPsyc 290B Psyc 290B June 1 2006June 1 2006

Outline:Outline:

1.1. Introduction to single-subject designsIntroduction to single-subject designs

2.2. Phases and phase changesPhases and phase changes

3.3. The ABAB reversal designThe ABAB reversal design

4.4. Dismantling or component-analysis designDismantling or component-analysis design

5.5. Multiple-baseline designsMultiple-baseline designs

6.6. Strengths and weaknesses of single-Strengths and weaknesses of single-subject designssubject designs

1. Introduction to single-subject 1. Introduction to single-subject designsdesigns

single-subject designs or single-case design are single-subject designs or single-case design are research designs that use the results from single research designs that use the results from single participant or subject to establish the existence of participant or subject to establish the existence of cause-and-effect relationshipscause-and-effect relationships

Whereas case studies belong to the group of Whereas case studies belong to the group of descriptive research strategies, single-case studies descriptive research strategies, single-case studies are experimentalare experimental

like time-series research, the single-subject approach like time-series research, the single-subject approach typically involves a series of observations made over typically involves a series of observations made over time but again single-subject designs are experimental time but again single-subject designs are experimental and time-series designs are quasi-experimentaland time-series designs are quasi-experimental

1. Introduction to single-subject 1. Introduction to single-subject designsdesigns

Evaluating the results from a single-subject Evaluating the results from a single-subject studystudy– the presentation and interpretation of results the presentation and interpretation of results

form a single-subject experiment are based on form a single-subject experiment are based on a a simple graph of the datasimple graph of the data

– because the results of a single-subject study do because the results of a single-subject study do not involve any traditional statistical methods, not involve any traditional statistical methods, researchers must rely on the researchers must rely on the visual inspectionvisual inspection of a graph to convey the meaning of their of a graph to convey the meaning of their resultsresults

2. Phases and phase changes2. Phases and phase changes

a phase is a series of observations of the same a phase is a series of observations of the same individual under the same conditionsindividual under the same conditions

when no treatment is being administered, the when no treatment is being administered, the observations are called observations are called baseline observations; baseline observations; a a series of baseline observations is called a series of baseline observations is called a baseline baseline phasephase and is identified by the letter A and is identified by the letter A

when a treatment is being administered, the when a treatment is being administered, the observations are called observations are called treatment observationstreatment observations. A . A series of treatment observations is called a series of treatment observations is called a treatment phasetreatment phase and is identified by the letter B. and is identified by the letter B.

2. Phases and phase changes2. Phases and phase changes

a consistent a consistent levellevel occurs when series of occurs when series of measurements are all approximately the same measurements are all approximately the same magnitude; in a graph, the series of data points magnitude; in a graph, the series of data points cluster around a horizontal linecluster around a horizontal line

a consistent a consistent trend trend occurs when the differences occurs when the differences from one measurement to the next are from one measurement to the next are consistently in the same direction and are consistently in the same direction and are approximantely of the same magnitude; in a graph approximantely of the same magnitude; in a graph the series of the data points cluster around a the series of the data points cluster around a sloping linesloping line

2. Phases and phase changes2. Phases and phase changes

the the stabilitystability of a set of observations refers to of a set of observations refers to the degree to which the observations show the degree to which the observations show a pattern of consistent level or consistent a pattern of consistent level or consistent trend; stable data may show minor trend; stable data may show minor variations from a perfectly consistent variations from a perfectly consistent pattern, but the variations should be pattern, but the variations should be relatively small and the linear pattern relatively small and the linear pattern relatively clearrelatively clear

3. The ABAB reversal design3. The ABAB reversal design

An ABAB design, also known as a reversal An ABAB design, also known as a reversal design, is a single-subject phase-change design, is a single-subject phase-change design consisting of four phases: a baseline design consisting of four phases: a baseline phase, a treatment phase, a return to phase, a treatment phase, a return to baseline phase, and a second treatment baseline phase, and a second treatment phasephase

The goal of the design is to demonstrate The goal of the design is to demonstrate that the treatment causes changes in the that the treatment causes changes in the participant’s behaviorparticipant’s behavior

3. The ABAB reversal design3. The ABAB reversal design

Limitations of the ABAB designLimitations of the ABAB design– It is not appropriate for evaluating treatments It is not appropriate for evaluating treatments

that are expected to have a permanent or long-that are expected to have a permanent or long-lasting effectlasting effect

– There is also the ethical question of withdrawing There is also the ethical question of withdrawing a successful treatmenta successful treatment

4. Dismantling or component-4. Dismantling or component-analysis designanalysis design

This design consists of a series of phases in which This design consists of a series of phases in which each phase adds or subtracts one component of a each phase adds or subtracts one component of a complex treatment to determine how each complex treatment to determine how each component contributes to the overall treatment component contributes to the overall treatment effectivenesseffectiveness

E.g. reward and punishment for biting behavior in E.g. reward and punishment for biting behavior in an autistic boyan autistic boyBC-B-BC-C-BCBC-B-BC-C-BCBC – combination of the reward and punishment BC – combination of the reward and punishment B – reward onlyB – reward onlyC – punishment onlyC – punishment only

5. Multiple-baseline designs5. Multiple-baseline designs

When initial When initial baseline phases baseline phases correspond to correspond to separate separate participants, the participants, the design is called design is called a a multiple-multiple-baseline across baseline across subjectssubjects

Example (left) Example (left) from Walker, from Walker, Shippen, Shippen, Alberto, Alberto, Houchins and Houchins and Cihak (2005)Cihak (2005)

5. Multiple-baseline designs5. Multiple-baseline designs

AdvantagesAdvantages– The major advantage of this design is that it eliminates The major advantage of this design is that it eliminates

the need for a reversal or return-to-baseline phase and the need for a reversal or return-to-baseline phase and is therefore well suited for evaluating treatment effects is therefore well suited for evaluating treatment effects that are permanent or long-lastingthat are permanent or long-lasting

DisadvantagesDisadvantages– The results can be compromised by individual The results can be compromised by individual

differences between participants or between behaviors differences between participants or between behaviors (e.g. one participant being more responsive to the (e.g. one participant being more responsive to the treatment than another)treatment than another)

6. Strengths and weaknesses of 6. Strengths and weaknesses of single-subject designssingle-subject designs

AdvantagesAdvantages– Researcher can establish a cause-and-effect relationship Researcher can establish a cause-and-effect relationship

between treatment and behavior using only a single between treatment and behavior using only a single participantparticipant

– Flexibility – development of the design depends on Flexibility – development of the design depends on participant’s responsesparticipant’s responses

DisadvantagesDisadvantages– Problem with generalizations since designs use only one Problem with generalizations since designs use only one

participantparticipant– Multiple observations can affect participant’s responsesMultiple observations can affect participant’s responses– Absence of statistical controls and reliance on visual Absence of statistical controls and reliance on visual

inspection of the datainspection of the data

ReferencesReferences

Walker B., Shippen M.E., Alberto P., Walker B., Shippen M.E., Alberto P., Houchins, D.E. & Cihak, D.F. (2005). Using Houchins, D.E. & Cihak, D.F. (2005). Using the the Expressive Writing ProgramExpressive Writing Program to Improve to Improve the Writing Skills of High School Students the Writing Skills of High School Students with Learning Disabilities. with Learning Disabilities. Learning Learning Disabilities Research and Practice, 20(3), Disabilities Research and Practice, 20(3), 175-183.175-183.