USING A CONTINGENT HEURISTIC APPROACH

Transcription

1 USING A CONTINGENT HEURISTIC APPROACH AND EYE GAZE TRACKING FOR THE USABILITY EVALUATION OF WEB SITES Pilun Piyasirivej MSc, Claremont Graduate University BEng (1 st Class Hons), Chulalongkorn University This thesis is presented for the degree of Doctor of Information Technology of Murdoch University October 2004

2 Declaration I declare that this thesis is my own account of my research and contains as its main content work which has not previously been submitted for a degree at any tertiary education institution. (Pilun Piyasirivej) ii

3 Abstract This thesis describes a research study in the field of Human-Computer Interaction (HCI), specifically usability evaluation. The research investigated ways to optimise the usability of Web sites. It specifically compared Flash and HTML versions of several different types of Web sites. The study commenced with a literature review regarding the process of usability evaluation of Web sites. Various usability evaluation methods and techniques were explored, and two emerging techniques were chosen for further investigation: (1) a contingent heuristic approach; and (2) eye gaze tracking. In order to confirm that these two techniques can be used effectively for Web site usability evaluations, two experiments were conducted to evaluate the usability of Web sites. The first experiment utilised an online questionnaire derived from the Website Usability Contingent Evaluation Tool (WUCET), which was based on the contingent heuristic approach. The second experiment involved eye gaze tracking with the facelab system, while participants interacted with Web sites of different types. Both experiments utilised Flash and HTML versions of the same set of Web sites. By analysing data collected from the experiments, comparisons between the usability of Flash and HTML versions were made. The results from quantitative and qualitative analyses of survey responses suggested that Flash version of Web sites, in general, provided higher usability than HTML version of Web sites, but eye gaze tracking data analyses showed no significant difference between the two versions. However, analyses of the eye tracking data were useful for improving understanding of the ways in which users interact with different versions of the Web sites. In addition, other influential factors that could affect the perceived usability of the Web sites, such as user s gender and previous experience with computers and the Web, were also considered. The results of the experiments showed that in regard to Flash and HTML implementations of Web sites, there was a difference in Web site usability perception patterns between male and female users, and also between users with long-term computer/web experience and users with short-term experience. In addition, a range of different types (purposes) of Web sites were utilised. In this study, selected Web sites fall into three broad categories according to their main purpose: (1) information; (2) entertainment; and (3) e-commerce. It was discovered that the type of Web sites also influenced the usability of Flash and HTML versions of Web sites, as perceived by users. iii

4 Contents ACKNOWLEDGEMENTS vii CHAPTER 1 OVERVIEW Introduction Structure of Thesis 4 CHAPTER 2 HUMAN-COMPUTER INTERACTION AND WEB USABILITY EVALUATION Introduction HCI Research: Past, Present, and Future Definitions of Usability Usability Evaluation Methods and Techniques Usability Evaluation of Web Sites Conclusion 28 CHAPTER 3 HEURISTIC APPROACHES IN WEB USABILITY EVALUATION Introduction Heuristic Evaluation Conducting Heuristic Evaluation Usability Questionnaire Conclusion 45 CHAPTER 4 CONTINGENT HEURISTIC APPROACH FOR WEB USABILITY EVALUATION Introduction Website Usability Contingent Evaluation Tool (WUCET) 48 iv

5 4.3 Web Usability Dimensions Conclusion 61 CHAPTER 5 EYE GAZE TRACKING FOR WEB USABILITY EVALUATION Introduction Eye Tracking Tools: Hardware and Software Web Usability Research with Eye Tracking Procedures for Web Usability Evaluation with Eye Tracking Validation of Eye Gaze Point Estimates Conclusion 87 CHAPTER 6 MACROMEDIA FLASH AND THE WEB Introduction History of the Web, HTML, and Flash The Uses of Flash on the Web Flash and Usability Usability Research Issues Regarding Flash Technology Conclusion 102 CHAPTER 7 RESEARCH DESIGN AND METHODOLOGY Introduction Quantitative and Qualitative Data Pilot Study of Usability Survey Experimental Design for the Phase One Experiment (Usability Survey) Method of Data Analysis for the Phase One Experiment Experimental Design for the Phase Two Experiment (Eye Gaze Tracking) Conclusion 122 CHAPTER 8 RESULTS OF THE PHASE ONE EXPERIMENT (USABILITY SURVEY) Introduction Quantitative Analysis Qualitative Analysis Usability of the Online Survey Conclusion 192 v

6 CHAPTER 9 RESULTS OF THE PHASE TWO EXPERIMENT (EYE GAZE TRACKING) Introduction Quantitative Analysis Preference for Web Site Versions (Flash or HTML) Comments on the Eye Gaze Tracking Experiment Analysis of Eye Gaze Point Accuracy Gaze Trails and Look Zones Conclusion 239 CHAPTER 10 CONCLUSIONS Topics Covered in the Research Summary of Main Results Suggestions for Future Research 246 APPENDIXES 249 Appendix 2A 249 Appendix 2B 251 Appendix 2C 252 Appendix 3A 253 Appendix 3B 255 Appendix 4A 256 Appendix 4B 259 Appendix 4C 261 Appendix 5A 264 Appendix 6A 265 Appendix 7A 282 Appendix 7B 285 Appendix 7C 291 Appendix 7D 298 Appendix 7E 312 Appendix 7F 314 Appendix 7G 316 Appendix 7H 318 Appendix 8A 320 Appendix 9A 322 Appendix 9B 325 BIBLIOGRAPHY 329 vi

7 Acknowledgements First and foremost, I would like to thank God for creating me and all the wonderful things in my life, I hope one day I can see You face-to-face and tell You how much I appreciate that every single day of my life is a blessing. Thank you with all of my heart to my supervisors, Dr. Andrew Turk and Dr. Fay Sudweeks, who have always been there for me and guided me through my research journey, I am eternally grateful. A special thanks to Russell Dunstan, Diana Adorno, Maurice McGinley, Nisha Weeramanthri, Adrian Bollig, and all others who have helped me with the tools and experiments. I also wish to thank Dr. Lance Fung, Dr. Tanya McGill, Dr. Graham Mann, Shri Rai, and all other friendly staff at Murdoch University s School of Information Technology for your help and support throughout the years. Thank you to Professor Duane Varan, Director of the Interactive Television Research Institute, for allowing me to use the eye gaze tracking laboratory and equipment in my experiment, and much thanks to all of those who participated. A special thanks to Dr. Nucharee Premchaiswadi, Dr. Varakorn Samakoses, and Dhurakijpundit University for believing in me and allowing me to fulfil my dream. Thanks to all of my friends and colleagues around the world for your support and encouragement, you know that I will always remember you. I would also like to thank all of my teachers and professors who educated me, because without you there would be no me. A very special thanks to Dr. Suvannee Vidhyapum for supporting me while I was in the United States, I thank you from the bottom of my heart. Last but not least, thank you mom, dad, grandma, and sis for your never-ending love, care, and support, I love you. This thesis is dedicated to the memory of Professor Magid Igbaria ( ), my professor and mentor, who contributed so much to information systems research. You will always be remembered. vii