Toward the optimal link structure of the cyber shopping mall

Int. J. Human-Computer Studies (2000) 52, 531}551doi:10.1006/ijhc.1999.0344Available online at http://www.idealibrary.com on

Toward the optimal link structure of the cyber shoppingmall

JINWOO KIM AND BYUNGGON YOO

Department of Business, Yonsei University, Seoul, 120-749, Korea.E-mails: [email protected], [email protected]

(Received 24 November 1998 and accepted in revised form 23 August 1999)

This study aims at identifying the optimal link structure, which is an essential require-ment for convenient and pleasant cyber shopping. To achieve the goal, this paperpresents a research framework in which di!erent types of links are hypothesized to causedi!erent patterns of customer navigation, which in turn is expected to in#uence cognitiveconvenience and emotional pleasure of cyber shopping. Based on two dimensions oflinks, link direction and link target, various links are classi"ed into "ve types; NBR(Neighbourhood), PAR (Parent), TOP, NEP (Nephew), and IND (Index). Two consecut-ive experiments were conducted in order to evaluate the cognitive and emotionalusability of various combinations of the "ve link types. Experimental results clearlyindicated that di!erent combinations of link types in#uenced customers' navigationpatterns, which in turn had e!ects on the convenience and pleasure of shopping. It wasfound that the combination of NBR, TOP and IND generated the optimal link structure,whereas PAR and NEP rather decreased the degree of shopping pleasure and conveni-ence. This paper concludes with its limitations and implications on the construction ofe!ective cyber shopping malls.

( 2000 Academic Press

1. Introduction

The in#uence of the Internet has been pervasive in almost all aspects of our society(Chon, 1996; Kraut, 1996). A prime example of this is the electronic commerce (EC) thatcan be de"ned as the transactions between two or more parties using the Internet(Kalakota & Whinston, 1997). Among various types of the EC, the EC betweenbusinesses and consumers (B-to-C EC) has the greatest potential to in#uence oureveryday life (Chung, 1996). The B-to-C EC, largely implemented in the form of Internetshopping malls, allows customers to learn about products, to purchase them withelectronic cash, and to receive the products immediately over the Internet (Rebello,Armstrong, Cortese & Bureau, 1996).

One of the most important requirements for constructing a successful cyber mall is anadequate link structure (Nielsin, 1996; Lynch and Horton, 1997; Rosenfeld and Morville,1998; Manning, McCarthy, & Souza, 1998). The link structure in a cyber shopping mallcan be compared to the hallways of an actual shopping mall, where customers navigatethrough the link structure to "nd their desired products. Without an adequate linkstructure, the customer may have di$culty "nding ways to reach target information incyber space. It was found that poor link structures caused 62% of cyber shoppers to give

1071-5819/00/030531#21 $35.00/0 ( 2000 Academic Press

532 J. KIM AND B. YOO

up looking for the item they wanted to buy on-line (Nielsen, 1998). In an EC environmentwhere the search cost for product information is nearly zero (Bakos, 1991), a customer'sinability to "nd target information can be detrimental to the respective shopping mall(Jamison, Gold & Jamison, 1997). Therefore, providing an adequate link structuresigni"es that the customer will be able to have a comfortable and pleasant shoppingexperience through e!ective navigation (Furnas, 1997). However, few empirical studieshave dealt with the key factors determining e!ective link structures of cyber shoppingmalls. Therefore, the objective of this study is to investigate empirically the impacts ofdi!erent link structures, and thereby to provide a basis for the optimal link structure thatpromotes convenience and pleasure in cyber shopping malls.

The structure of this paper is as follows. The next section contains the study'stheoretical background and hypotheses, while Section 3 explains the general procedureof the two consecutive experiments conducted in this study. Sections 4 and 5 contain theresults from the two experiments, and Section 6 concludes with the study's contributionsand limitations.

2. Add-on links for shopping pleasure and convenience

A cyber shopping mall is composed of numerous nodes and links within the hypertextsystem (Bieber & Kimbrough, 1992). In the hypertext system, each information unit canbe seen as a node that contains speci"c piece of information or ideas (Halasz & Schwartz,1994). Connection among the nodes is a link that falls under the hypertext system'srelationship structure because it associates the related information nodes (Preece,Rogers, Sharp, Benyon, Holland & Carey, 1994). Using the node and link structures,hypertext enables users to search for the information needed without the constraint oflinearity that has been usually assumed in traditional books (Bieber, Vitali, Ashman,Balasubramanian & Oinas-Kukkonen, 1997).

The nodes and links of such hypertext system assume various structural formsaccording to the system's characteristics. The node structure signi"es an organizationalstructure of the overall information. Examples of the node structure include a linearstructure such as guided tours and a hierarchical structure that is most frequently used incyber shopping malls (Morris & Hinrichs, 1996). Meanwhile, a link structure is com-posed of various connective associations among each node. Links are generally categor-ized as either basic or add-on links. Basic links provide a web site with a set offundamental connections that are pre-determined by its node structure. For example, thehierarchical node structure requires the basic links that move &&down'' to a lower level ormove &&up'' to a higher level of the hierarchy. Also, if the node structure is linear, the&&next'' and &&previous'' buttons are required to be basic links.

Add-on links, on the other hand, are additionally presented to further improve thenavigation behaviour. These add-ons are particularly useful when the basic links cannotfacilitate e!ective navigation by themselves (Furnas, 1997). However, too many add-onlinks will not only confuse the users' logical understanding of information (Morris& Hinrichs, 1996), but also lead the shoppers to unexpected destinations in the cybermall (Edward & Hardman, 1989). Moreover, if add-on links are not properly presentedwithin the cyber mall, customers may experience disorientation and cognitive overload(Lynch & Horton, 1997). Disorientation is commonly referred to as being &&lost in space'',

TOWARD THE OPTIMAL LINK STRUCTURE OF THE CYBER SHOPPING MALL 533

where the users lose track of their current place or destination (Conklin, 1987). Mean-while, cognitive overload is increased because the users must compile and organize anabundance of information while following various add-on links. Therefore, if add-onlinks are not adequately provided within a cyber shopping mall, users will face theproblems of either losing direction while searching for product information or amassingincreased cognitive overload while gathering necessary information (Rosenfeld & Mor-ville, 1998).

This study focuses on the add-on links of the cyber shopping mall, since the basic linkshave been mostly pre-determined by the mall's node structure and not much room is leftfor improving shopping experience. As most cyber shopping malls are hierarchicallyorganized according to product classi"cations, it is assumed that the node structure inthis study is also hierarchical and the basic links consist of &&up'' and &&down'' buttons. Thecyber shopping malls currently operating provide various forms of add-on links that canbe classi"ed into "ve categories based on two dimensions: link direction and link target.The link direction denotes a point of compass along the hierarchical structure, and itsdirection is classi"ed into three patterns: upward, downward and horizontal. The linktarget signi"es the dynamic adjustment of the target destination. The target destinationcan be altered dynamically according to the current position of customers, or it can be"xed to a pre-determined place regardless of their current location. Table 1 classi"esadd-on links based on these two dimensions.

TABLE 1Classi,cation of add-on links

Target

Fixed Variable

Direction Upward TOP PARHorizontal N/As NBRDownward IND NEP

sAn add-on link with horizontal movement and a "xed destination is impossible to exist,and so it has been excluded from this study.

First, the direction of the TOP link is upward and the users move to a pre-determineddestination regardless of their current position. A prime example within cyber shoppingmalls is the &&Home'' button that is anchored to the mall's homepage. Second, thedirection of PAR (parent) link is also upward, but it is a link with which the users moveone level up from their current position along the hierarchical structure. For example, ifthe user is located at a notebook computer corner, the PAR link allows the user to moveto the hardware store in which the notebook corner is included. Moreover, it also allowsthe user to move not only to the hardware store but also to the software store at the samehierarchical level. Third, the NBR (neighbourhood) link is an add-on link where itsmovement is horizontal and its destination target changes according to the currenthierarchical level. For instance, if a customer is located at a notebook computer corner,the NBR link allows movement to the desktop or palm-top computer corners that are on


the same hierarchical level. Fourth, the IND (index) link is an add-on link where thetarget is "xed at the lowest level regardless of the user's current position, and a primaryexample of such is the index to the individual products. Finally, the NEP (nephew) link ismuch like the PAR link in that the movement target changes relative to the currentposition of the hierarchical level, but di!ers in that the movement is one level down,rather than up. An example would be where the user is situated in a notebook computercorner viewing a product list and is able to move directly to the product list ofa neighbouring printer corner. Based on the classi"cation of add-on links in Table 1, thisstudy conducted experiments to investigate the e!ects of the various link structure interms of cognitive convenience and emotional pleasure. The overall research frameworkof this study is presented in Figure 1.

FIGURE 1. Overall research framework.

As seen above, the user's navigation pattern is expected to vary according to theprovision of di!erent add-on links such as NBR, PAR, TOP, NEP and IND. Here, thenavigation pattern indicates the user's movement through each level within the shoppingmall's hierarchical structure, under a given link structure. Moreover, this study hypothe-sizes that a subject's navigation pattern has e!ects on his/her cognitive convenience andemotional pleasure. Cognitive convenience encompasses the cognitive dimensions ofusability the interface provides in order for users to "nd target information e$ciently(Nielson, 1993). Emotional pleasure signi"es the basic emotions perceived by the shoppersuch as shopping satisfaction or fun (Kim & Moon, 1998). We measure both cognitiveconvenience and emotional pleasure, because it is the cyber shopping mall that isresponsible for providing a convenient and pleasant shopping environment, and the linkstructure is expected to play a vital role in bringing about such results.

3. Experimental procedure

3.1. CURRENT USE OF ADD-ON LINKS

Prior to conducting the experiments, currently operating cyber shopping malls wereinvestigated in order to "nd out how the add-on links categorized in Table 1 are actuallybeing utilized. The pre-investigation was conducted using several directories of Internetshopping malls, including All-internet Shopping Directory and World Shopping Direc-tory. The result of the pre-investigation is exempli"ed in Table 2.

TABLE 2Examples of add-on links provided in real cyber shopping malls

Add-onLinks

URL where Provided

NBR http://www.branchmall.com,http://www.shinbiro.com/&grand/home.htmhttp://www.emilysgifts.com/http://www.abbington.comhttp://www.homepage.com/, http://www.ishopper.com/http://www.supermarket.net, http://internet.shopping.co.kr

PAR http://www.shinbiro.com/plaza/index.htm, http://internet.shopping.co.krhttps://cybermall.co.kr/shopping/intro.asp, http://www.hansolcs.co.kr/default.htmhttp://www.emilysgifts.com/

TOP http://www.branchmall.com, http://www.hansolcs.co.kr/default.htmhttp://www.pacprod.com,http://www.shinbimall.com/shopping/shopinn/index.html,http://www.cybersuperstores.com/, http://www.choicemall.com/indexnl.htmlhttp://internet.shopping.co.kr

NEP http://www.metaland.comIND http://www.AccessNewAge.com/, http://www.itl.net/,

http://www.shopsite.com/


It was revealed that at least one of the "ve types of add-on links was utilized by almostall shopping malls, and more than one type of add-on links was simultaneously used byseveral malls. For example, both NBR and TOP links were provided in the case ofBranchmall (http://www.branchmall.com), while Lotte Department Store (http://inter-net.shopping.co.kr) presented NBR, PAR and TOP links simultaneously. The resultsalso indicated that horizontal and upward add-on links (NBR, TOP and PAR) werefound to be provided more frequently than the downward links (IND and NEP). It canbe inferred that the horizontal and upward links are used more frequently because theyare complementary to the basic links of the hierarchical structure that inherently weighless on the upward and horizontal rather than the downward movements (Rosenfeld& Morville, 1998).

3.2. EXPERIMENTAL MATERIAL

In order to conduct usability tests for each of the add-on links, the features of theexperimental materials had to be controlled. However, the currently operating cybershopping malls are di!erent not only in terms of the provided types of add-on links butalso of the number of products, the depth and breadth of the hierarchy and graphicaldesigns. Therefore, this study developed several versions of an experimental cybershopping mall to control the depth, breadth, graphics and product numbers to be all thesame, but only with di!erent set of add-on links.

The node structure of the experimental shopping mall is hierarchically organized, as isthe case with most cyber shopping malls under operation. Based on the popular product

FIGURE 2. The structure of mall and add-on links.


characterization, the node structure is organized into "ve hierarchical levels (Morris& Hinrichs, 1996). The top level contains one home-page, and the second level containsa total of seven departments pages (e.g. Electronics Department). The third level includesa total of 18 stores (e.g. Computer Store), the fourth level a total of 66 corners (e.g.Notebook Computer Corner) and the "nal level a total of 674 products (e.g. ToshibaSatellite 2000). Also, in order to increase the external validity of the experimental mall,actual product information from a currently operating cyber shopping mall was usedunder permission from the source. The hierarchical structure of the experimental shop-ping mall, including add-on links, is presented in Figure 2.

Figure 3 shows the page of household electronics corner within the experimentalshopping mall where all "ve add-on links are provided. The TOP buttons at the top ofthe page are links that allow direct movement up to the department level. For example,clicking the &&Supermarket'' button would let the user move straight to the supermarketdepartment. Also if the user wishes to move to a corner neighbouring the householdelectronics corner, she/he can click on the NBR link (e.g. Audio/Video) located within theframe box in the centre of the screen. Meanwhile, the product information links underthe Air Conditioner or Audio/Video corner are NEP links (e.g. Camcorder) that allowdirect movement to the products within those corners. The PAR link, which allowsmovement up one level to another store from a corner level, is situated on the right sideof the screen. For instance, by clicking on the &&Computer'' button, the user is able tomove from the household electronics corner to the Computer Store that neighboursthe Electronics Store, the parent node of the current corner. Finally, the alphabeticalindex located at the bottom of the screen is an IND link that allows direct movementto products in other stores or corners (e.g. Animation Video). If a version of the

FIGURE 3. Example of a corner page layout with the "ve links types.


experimental mall provided some of the add-on links, they were shown at the same placein all the pages of the shopping mall.

3.3. EXPERIMENTAL DESIGN

A total of 32 versions of experimental shopping malls was needed in order to conducta comprehensive test on the entire combination of the "ve add-on link types (provision ofthe TOP link]PAR link]NBR link]NEP link]IND link"2]2]2]2]2"32).However, carrying out detailed evaluations on the entire 32 shopping malls requiresa vast amount of time and e!ort, and the cost-e!ectiveness is far from certain. Therefore,in order to balance comprehensiveness and cost-e!ectiveness of research, this studyconducted two consecutive experiments. The "rst experiment dealt with only parts of the"ve add-on links, identifying a tentative optimal link structure. On top of the tentativeoptimal structure, the second experiment added those of the "ve links that were notevaluated in the "rst experiment, coming up with the "nal optimal link structure.

The "rst experiment evaluated three of the add-on links; NBR, PAR and TOP. Thethree links were selected because they were expected to have greater possibilities ofalleviating navigational di$culties caused by limitations of the hierarchical structure(Rosenfeld & Morville, 1998). Since the hierarchy's basic links mostly focused ondownward movement from a higher level to a lower level, PAR and TOP links which


were upward, and NBR link which was horizontal, were utilized more frequently tocomplement the basic links. Therefore, the "rst experiment was carried out using a totalof eight versions of the experimental mall with the combinations of only NBR, PAR andTOP links. On the other hand, the combinations of IND and NEP links were evaluatedlater in the second experiment using four versions of the experimental shopping mall.

3.4. EXPERIMENTAL PROCEDURE

The two experiments were conducted with similar groups of subjects using the sameexperimental procedure. The subjects were all undergraduate students enrolled in anintroductory class to computer systems. They participated in the experiment for partialcredit of their required course. The reasons for selecting university students in their 20s asexperimental subjects were because people in their age group make up over 50% of allInternet users and over 70% of the web users have post-secondary education (Ho!man,Kalsbeek & Novak, 1996).

3.4.1. Pre-questionnaireThe "rst step of the experiment consisted of individual pre-questionnaires for eachsubject. The pre-questionnaire was used to determine whether or not there were anydiscrepancies among the subjects in terms of prior experience with the Internet andWorld Wide Web. Also, the pre-questionnaire gathered information on the subjects'prior experiences and attitudes towards cyber shopping malls.

3.4.2. Experimental tasks and server log xlesAfter answering the pre-questionnaire, subjects were assigned a total of 12 shoppingtasks and were requested to purchase the most appropriate product speci"ed by eachtask in the experiment. These tasks were presented to the subjects one by one ina random order.

The server log "les were used in order to collect the users' navigation pattern data. Thelog data include server connection time, all pages viewed along with a timeline and theterminal IP address of requested pages. It can be inferred from the log data on whichadd-on links were utilized through the recorded history of pages over a time sequence.

3.4.3. Post-questionnaireDirectly following each task, the computer monitor showed a post-questionnaire whichasked the subjects about the degree of cognitive convenience and emotional pleasureperceived by the subjects while purchasing an appropriate product under each task. Thesubjects used the mouse to record their responses, and these were directly stored withinthe system by way of electronic mail. The actual post-questionnaire consisted of "vequestions. The "rst three questions asked the subjects about the degree of perceivedcognitive convenience such as ease of moving to the target page, the degree of conveni-ence in looking around the mall and the ease of comparing multiple products. On theother hand, the last two questions measured the degree of emotional pleasure perceivedby the subjects while purchasing an appropriate product under each task. The twoquestions asked the level of satisfaction and interests during the shopping process.


4. Results of the first experiment

As previously mentioned, the "rst experiment evaluated three (NBR, PAR, TOP) add-onlinks which were expected to be relatively more important than the other two (NEP andIND). To verify the e!ectiveness of these links, eight versions of experimental shoppingmalls were developed based on the combination of NBR, PAR and TOP links. Eachversion of the experimental mall and its relevant add-on links are given in Table 3. Forexample, version 1 of the experimental mall did not have any additional links, whereasversion 2 had only PAR provided. A total of 172 subjects were randomly assigned to theeight di!erent versions of the experimental shopping mall.

TABLE 3Eight versions of the experimental shopping mall

Mall NBR PAR TOP NEP IND

1 X X X X X2 X O X X X3 X X O X X4 O X X X X5 O O X X X6 O X O X X7 X O O X X8 O O O X X

O, provided; X, not provided.

4.1. PRE-QUESTIONNAIRE

The pre-questionnaire was analysed using the ANOVA method where the three add-onlinks were the independent variables and subjects' responses were the dependent vari-ables. The results of the analysis revealed that there existed no signi"cant variancesamong the subject groups in terms of the frequency of Internet usage (F"1.68, NS) andprior experiences of cyber shopping (F"1.13, ns). Also, all the subjects in each groupgenerally showed a positive attitude towards cyber shopping without any signi"cantdi!erence among di!erent groups (F"1.70, ns).

4.2. POST-QUESTIONNAIRE

The post-questionnaire focused on the e!ects of the add-on links with regard to theconvenience of navigation and shopping pleasure perceived by the subjects in eachgroup. For this purpose, a factor analysis was performed initially to "nd out whetherquestions in the post-questionnaire revealed accurate accounts of convenience andpleasure experienced by the subjects. The results of the factor analysis using a varimaxrotation clearly indicated that questions d1, d2 and d3 in the post-questionnaireadequately assessed the degree of cognitive convenience (Cronbach a coe$cient"0.86)

TABLE 4Results of post-questionnaire (a"0.01)

Post-questionnaire Main e!ect Interaction e!ect

Factor 1}cognitive convenience NBR (F"27.82, p(0.01)PAR (F"6.86, p(0.01)

NBR*TOP (F"17.26, p(0.01)PAR*TOP (F"20.86, p(0.01)

Factor 2*emotional pleasure TOP (F"8.09, p(0.01) NBR*TOP (F"22.06, p(0.01)PAR*NBR (F"8.33, p(0.01)

FIGURE 4. Interaction e!ects between NBR and TOP: *r*, TOP ]; *j*, TOP 0.


while questions d4 and d5 measured emotional pleasure (Cronbach a coe$c-ient"0.72). Consequently, an ANOVA test was conducted using the factor scores as thedependent variables, and the NBR, PAR, TOP links as the independent variables. Theresults of the ANOVA test are shown in Table 4.

First, NBR (F"27.82, p(0.01) and PAR (F"6.86, p(0.01) were found to producemain e!ects in the level of cognitive convenience, while TOP (F"8.09, p(0.01) causeda main e!ect in the level of emotional pleasure. In other words, when NBR (given: 0.1131,not given: !0.1132) and PAR (given: 0.0614, not given: !0.0615) were provided, thesubjects found it more convenient to search for product information or navigate throughthe site, while TOP (given: 0.0591, not given: !0.0605) enhanced their degree ofshopping pleasure.

More interesting results were revealed in the interaction e!ects among the add-onlinks as shown in Figures 4 and 5. First, convenience and pleasure increased consistentlythrough a complementary interaction e!ect when both NBR and TOP links wereprovided as shown in Figure 4.

The perceived degree of convenience was much higher when NBR and TOP links wereprovided together (0.2273) than when only NBR (!0.0010) or TOP (!0.1780) wasprovided separately. Similarly, subjects' degree of shopping pleasure increased signi"-cantly when NBR and TOP links were provided together (0.1655) compared with whenNBR (!0.1576) or TOP (!0.0449) was provided separately.

FIGURE 5. Con#icting interaction e!ects with PAR: *r*, TOP ]; *j*, TOP 0.


On the other hand, providing PAR along with other add-on links produced a con#ict-ing interaction e!ect where the level of convenience or pleasure decreased as shown inFigure 5.

The perceived convenience decreased signi"cantly when PAR and TOP links wereprovided together (!0.0083), compared to when only PAR (0.1345) or TOP (0.0541)link was provided separately. Similarly, the subjects' perception of pleasure decreaseddrastically when PAR and NBR links were provided together (!0.0307) compared withwhen PAR (0.0814) or NBR (0.0402) was provided separately.

In summary, it can be noted that NBR and PAR were seen to enhance the perceivedconvenience and TOP was found to increase the degree of shopping pleasure. Aninteresting aspect is the consistency of complementary interaction e!ects between NBRand TOP, and con#icting interaction e!ects between PAR and other add-on links. Inother words, when NBR and TOP were provided together, the users' perceived degree ofconvenience and pleasure increased consistently, while providing PAR along with theother two links drastically decreased one's convenience and pleasure consistently. Inorder to further explain the main and interaction e!ects of add-on links, results on thelog data analysis will be presented in the next section.

4.3. LOG DATA ANALYSIS

The purpose of the log data analysis is to "nd out the e!ects of add-on links upon theusers' navigation patterns and thereby to infer these e!ects upon the users' perceptions ofconvenience and pleasure. The next section will explain each result from the post-questionnaires, using the navigation patterns of the experimental groups.

4.3.1. Main ewect of NBR in the navigation patternThe post-questionnaire analysis revealed that subjects who were provided with NBRfound it more convenient to navigate through the mall than those who were not given thelink (given: 0.1131, not given: !0.1132). In order to explain the main e!ect of NBR, the

FIGURE 6. Aggregate navigation pattern of Groups 1 and 4.


aggregate navigation pattern of all subjects in Group 1 (only basic links provided) andGroup 4 (NBR added) are compared in Figure 6. In the "gure, the rectangular boxsigni"es each level within the shopping mall's hierarchy, and the arrow pointing rightstands for a down movement and left for an up movement. The percentage (%) withineach box represents the frequency of NBR usage within each level.

As shown in Figure 6, it is clear that the frequency of up/down movement within theshopping mall's hierarchy was considerably less in Group 4 than was in Group 1.Especially, at the product level, the percentage of up/down movement decreased from18.11 and 26.01%, to 4.99 and 12.54%, respectively. This reveals a reduction of about14%, which can be credited to the use of NBR whose usage in this level was up to31.08%. Therefore, the subjects without the NBR link were forced to navigate up anddown in order to view various products, whereas those with NBR could view alternativeproducts directly without repeating up and down. This may explain the main e!ect ofNBR where subjects stated that shopping convenience was much higher with NBR.

4.3.2. Main ewect of PAR in the navigation patternThe post-questionnaire analysis revealed that PAR made the navigation more conve-nient (given: 0.0614, not given: !0.0615). In order to investigate such results, thenavigation patterns of Group 1 (basic links only) and Group 2 (PAR provided) werecompared in Figure 7, where the movement frequency using PAR is expressed with anarrow pointing left below each level box.

Group 1's movement from the department level up to the homepage level (3.03%) andfrom the store level to the department level (4.65%) decreased to 1.14 and 1.83% inGroup 2, respectively. Also, Group 1's movement from the corner level up to the storelevel (8.42%) and from the product information level up to the corner level (18.11%)decreased to 5.98 and 15.62% in Group 2, respectively. Therefore, PAR lessened theinconveniences in navigation to other departments, stores and corners, which may be thereason why subjects perceived a higher level of cognitive convenience when PAR wasprovided.

4.3.3. Main ewect of TOP in navigation patternThe results of the post-questionnaire analysis revealed that the subjects found shoppingmore pleasurable with TOP than without (given: 0.0591, not given: !0.0605). In order

FIGURE 7. Aggregate navigation patterns of Groups 1 and 2.


to explain such results, a comparative analysis of navigation patterns was conducted onGroup 1 (basic links only) and Group 3 (TOP provided) in Figure 8.

FIGURE 8. Aggregate navigation pattern of Group 3.

It indicates that the movement from the department to the homepage and from thestore to the department levels has been decreased from 3.03 and 4.65% of Group 1 to0.63 and 2.44% of Group 3, respectively. These results indicate that TOP allowed usersto move to other departments right away when they could not "nd the informationneeded at their current location. In other words, TOP enables users to start a brand newnavigation whenever necessary without going through all the pages at the store andcorner levels, which may increase the shopping pleasure.

4.3.4. Interaction ewect of NBR and TOP on navigation patternThe levels of convenience and pleasure increased signi"cantly when both NBR and TOPwere provided simultaneously. In order to explain these interaction e!ects, the navi-gation pattern of Group 6 (both NBR and TOP) is compared with Group 3 (TOP only)and Group 4 (NBR only). At the product level, Group 6 (shown in Figure 9) was found touse TOP more frequently than Group 3 (0.98% for Group 3 vs. 2.37% for Group 6) andto use NBR less frequently than Group 4 (31.08% for Group 4 vs. 25.09% for Group 6).Also, Group 6 was found to use the UP link less frequently than Groups 3 and 4. We can



infer from these results that subjects had to use lots of the up links if only NBR wasprovided, whereas they could move to other departments directly without using severalup links if TOP was provided.

Therefore, subjects might feel a higher degree of convenience and pleasure with NBRand TOP links together, because the two links were clearly distinguishable and provideddistinctive functions. The NBR and TOP links are evidently separable, since the direc-tion of NBR is horizontal and its target is variable, whereas the direction of TOP isupward and its target is "xed. Moreover, the subjects could use the NBR link mostly tocompare multiple products within their neighbourhood, whereas the TOP link could beused to start a brand new search when the local search using NBR could not locateappropriate products.

4.3.5. Interaction ewect of PAR and TOP in navigation patternCognitive convenience decreased rather signi"cantly when both PAR and TOP were

provided, compared to the cases where either one was provided. In order to investigatethe reason for the con#icting interaction e!ect, log data of Group 7 (with both TOP andPAR) is presented in Figure 10 and compared with Group 2 (PAR only) and Group3 (TOP only).


The usage of PAR at the store level has been decreased from 2.97% of Group 2 to0.61% of Group 7. Similarly, the usage of TOP at the store level also has been decreasedfrom 1.43% of Group 3 to 0.66% of Group 7. We can infer that these decreases in usagemay have resulted from the redundancy between PAR and TOP in Group 7. The twoadd-on links provide the same function of moving from the store to the departmentlevels, while the need to move from the store to the department level is rather constant.This may cause confusion among subjects in terms of which links to choose, and this


kind of confusion in turn results in the con#icting interaction e!ect in terms of cognitiveconvenience.

In summary, one of the reasons for the con#icting interaction e!ects might be theredundancy between PAR and TOP. At the store level, the PAR and TOP links providedthe same function of moving from the store to the department levels, which might causeconfusion among subjects.

4.3.6. Interaction ewect of Par and NBR in navigation patternThe level of emotional pleasure decreased signi"cantly when both NBR and PAR wereprovided simultaneously compared to the case when only one of them was provided. Inorder to explain the interaction e!ect, we will compare the aggregate navigation patternof Group 5 (as shown in Figure 11) with Group 4 (NBR only) and Group 2 (PAR only).


At the product level, Group 5 was found to use NBR less frequently than Group4 (31.08% in Group 4, 24.57% in Group 5), and to use PAR more frequently thanGroup 2 (2.97% in Group 2, 4.41% in Group 5). These results indicate that subjects inGroup 5 may be confused between PAR and NBR. Those who actually used the PARwith the intent to compare individual products with NBR would have been confused interms of the context in product search, which in turn caused the con#icting interactione!ects of emotional pleasure.

In conclusion, PAR and the other two add-on links produced con#icting interactione!ects, because PAR and TOP are redundant at the store level, while PAR and NBR areconfusing at the product level. Therefore, if PAR were provided with the other twoadd-on links, the cognitive convenience and emotional pleasure would decrease. On theother hand, the NBR and TOP provide a positive interaction when both of them wereprovided simultaneously. Therefore, the "rst experiment in this study indicates that thecyber shopping mall with the NBR and TOP but without PAR would be the tentativeoptimal combination to maximize cognitive convenience and emotional pleasure.

5. Results of the second experiment

The second experiment was designed based on the result of the "rst experiment in orderto investigate additional e!ects of the NEP and IND links with regard to cognitiveconvenience and emotional pleasure. The version of the shopping mall with NBR andTOP was used again as the control group and three other versions were added in thesecond experiment. Table 5 presents the four versions of experimental shopping malls.

TABLE 5Four versions of the experimental shopping mall

Mall NBR PAR TOP NEP IND

6 O X O X X9 O X O O X

10 O X O X O11 O X O O O

TABLE 6Results of post-questionnaire

Post-questionnaire Main e!ect Interaction e!ect

Factor 1*cognitive convenience IND(F"4.34, p(0.05) NSFactor 2*emotional pleasure NEP(F"4.46, p(0.05) NS


A total of 67 subjects whose backgrounds were similar to those in the "rst experimentparticipated in the second experiment, and the same experimental procedure was usedagain in the second experiment.

5.1. PRE-QUESTIONNAIRE

Subjects' responses to the pre-questionnaire were analysed again using the ANOVAmethod, where IND and NEP links were the independent variables. It was again foundthat there existed no signi"cant variances among the subject groups on the frequency ofthe Internet usage (F"2.89, ns), their previous experiences with a cyber shopping(F"0.93, ns), and their attitude towards the Internet shopping (F"1.93, ns).

5.2. POST-QUESTIONNAIRE

In order to investigate the dimensionality of the post-questionnaire, we conducteda factor analysis using the varimax rotation. It was found that the "rst three questions inthe post-questionnaire measured the cognitive convenience (Cronbach a coe$c-ient"0.88) faithfully, whereas the last two questions measured the emotional pleasure(Cronbach a coe$cient"0.64) marginally, but good enough to proceed further with theanalysis. Consequently, an ANOVA test was conducted using the factor scores ofconvenience and pleasure as the dependent variables, and the two add-on links as theindependent variables. The results of the ANOVA test are shown in Table 6.

The results indicate that the IND link produced a signi"cant main e!ect in terms ofcognitive convenience (F"4.34, p(0.05) and the NEP link caused a considerable maine!ect in terms of emotional pleasure (F"4.46, p(0.05). Subjects felt higher cognitiveconvenience when IND was provided (given: 0.0630, not given: !0.0674), whereas theiremotional pleasure rather decreased when the NEP link was provided (given: !0.0602,



not given: 0.0674). No interaction e!ects were observed. In order to explain the results inthe post-questionnaire, we conducted a detailed analysis of the navigation log.

5.3. LOG DATA ANALYSIS

5.3.1. Main ewect of IND in navigation patternIn order to explain the main e!ect of IND, this section compares the aggre-gate navigation pattern between Group 10 and the control group (Group 6) as inFigure 12.

The aggregate navigation pattern of Group 10 shows that IND was used mostly at theproduct level (0.45%). Moreover, compared to the control group, the UP link was usedless frequently by Group 10 at all levels (3.65, 3.77 and 1.63% in the control group; 1.36,0.97 and 0.39% in Group 10). We can infer from the results that the UP was lessfrequently used because the subjects could refer to individual products directly usingIND. The e!ect was especially strong at the product level. If there was no IND providedat the product level, and if a user wanted to view a product located in other departments,she/he had to move back to the department level and move down to the product level.Therefore, even though the usage rate of IND was relatively low, it produced a positivemain e!ect in terms of the cognitive convenience by shortening the route betweenproducts in di!erent departments.

5.3.2. Main ewect of NEP in navigation patternIn order to explain the main e!ect of NEP, we compare in this section the navigationpattern of Group 9 and the control group. The aggregate navigation patterns of Group9 and control group are shown in Figure 13.

The patterns clearly indicate that, compared to the control group, Group 9 used theNBR less frequently at the store (2.02% for the control, 0.43% for Group 9) and at the



corner level (5.32% for the control, 0.49 for Group 9). On the other hand, Group 9 usedthe TOP more frequently at the product level (2.37% for the control, 5.07% for Group 9).The use of NBR decreased because NBR and NEP might be confusing at the store andcorner level. If subjects misunderstood NEP as NBR at the store or corner level, theyhappened to move directly to products in other stores or corners, where they couldneither recognize their current location nor move back to their prior location. So, theymight feel confused and tend to use TOP to start a brand new search, which may be thereason why Group 9 used more TOP links at the product level. Therefore, NEP wasconfused with NBR, which may dislocate the subjects and produce a negative main e!ecton the shopping pleasure.

6. Conclusion and discussion

The main goal of this research is to identify the optimal link structure for cyber shoppingmalls of the hierarchical structure. In order to accomplish this goal, a research frame-work was constructed in which add-on links were hypothesized to a!ect customers'navigation patterns and the consequent changes in the navigation patterns were ex-pected to in#uence the degree of shopping pleasure and convenience. Two consecutiveexperiments were conducted in order to prove the research framework.

The results of the experiments revealed that di!erent add-on links in#uenced thenavigation patterns of cyber shoppers. The NBR was found to be used most heavilyamong the various add-on links, and decreased the use of tedious up and downmovements signi"cantly. Moreover, NBR that enables a local comparison works wellwith TOP that allows customers to start a brand new search when they are through withtheir shopping at the current locations. On the other hand, the function of PAR links wasoften confused or overlapped with the other two add-on links; consequently, its use wasdecreased. The IND provided a shortcut to product information located in other stores


or corners, although it was not used as frequently as NBR. Finally, NEP had a low levelof usage and people often seemed to confuse it with NBR, causing them to use TOP morefrequently to go back to the beginning.

The results of the post-questionnaire also revealed that di!erent navigation patternscaused by di!erent add-on links in#uenced the cognitive convenience and emotionalpleasure. The NBR and TOP together increased the cognitive convenience and emo-tional pleasure, while the combination of PAR with TOP or NBR rather decreased thelevel of shopping convenience and pleasure. Also IND increased the shopping conveni-ence, whereas the NEP link decreased shopping pleasure.

In conclusion, the results indicate that the combination of NBR, TOP and IND linkswould maximize the shopping convenience and pleasure, whereas PAR and NEP linksshould be avoided from the link structure of cyber shopping malls. Therefore, it turnedout that the degree of cognitive convenience and emotional pleasure was not increasedlinearly in proportion to the number of add-on links provided. In order to be included inthe optimal link structure, each add-on link should be clearly distinguishable from otherlinks, and provide a distinctive role in navigating through the cyber mall. Otherwise,add-on links that provide vague and redundant functions would confuse the subjects,which in turn might cause the negative impacts on their shopping pleasure and conveni-ence.

This research has several limitations. First, in order to evaluate the overall usability ofthe "ve types of add-on links, experiments must be conducted with 32 versions of malls.However, this study reduced the number of di!erent versions to 11 in total by adoptingan incremental evaluation strategy. The strategy was selected based on the assumptionthat upward and horizontal movements, compared to the downward moves, areexpected to overcome the limits of the hierarchical structure more e!ectively. So,the upward and horizontal moves were evaluated "rst, a tentative optimal combinationof TOP and NBR was devised, and then the downward links were evaluated. Theassumption has been supported partially by the study results that add-on links evaluatedin the "rst experiment showed highly signi"cant e!ects on the convenience and pleasurefactors (p(0.01), whereas those evaluated in the second experiment had only marginale!ects (p(0.05). However, in order to be more con"dent about the optimal linkstructure of cyber shopping malls, more direct empirical results should be achievedin a future study.

Second, this study classi"ed add-on links based on the link direction and target.However, add-on links can be classi"ed based on dimensions other than these two. Forexample, this study focuses on the add-on links of the global navigation system that areprovided in every page of the shopping mall. However, add-on links in the localnavigation systems such as &&hot sales'' or &&new features'' are also used frequently in manyshopping malls currently under operation. This study focused on the global navigationbecause they are assumed to have more powerful impact on shopping pleasure andconvenience since they are provided in a broader scope compared to the local navigationsystem. However, a more complete study about the optimal link structure should includea thorough evaluation of the local navigation system.

Finally, this study also has several methodological limitations. The two experiments inthis study were conducted in a group setting, so this study cannot present explicit reasonswhy di!erent add-on links caused di!erent levels of cognitive convenience and emotional


pleasure. Therefore, this study had to infer the reason of the cognitive and emotionaldi!erences indirectly based on the navigation patterns recorded in the server log data.Verbal protocols of individual subjects should be analysed in a future experiment inorder to provide more direct explanations. Also, participants in this study are mostlycollege students in their early 20s. In order to increase its external validity, a future studyshould include subjects with di!erent backgrounds at di!erent ages.

Even with these limitations, it is believed that the study provides important theoret-ical, as well as practical contributions to the link structure of cyber malls. Froma theoretical perspective, this study constructed a comprehensive research frameworkthat includes add-on links, navigation patterns and shopping convenience and pleasure.From a practical perspective, it provided empirical data on the optimal link structurethat is essential to the success of cyber shopping malls. These results could be applied toother web information systems that have similar hierarchical structures to cyber shop-ping malls.

This research was funded by Soft Science Research Grant from Korean Ministry of Scienceand Technology. The authors appreciate cooperation from the members of the Human ComputerInteraction Lab at Yonsei University, David Hahn and President K.H. Lee of DacomInterpark.

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Paper accepted for publication by Associate Editor, Dr M. Coombs

Toward the optimal link structure of the cyber shopping mall

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