Does the Size of Personalized Menus Affect User Performance?

Problem statement: To date, researchers have personalized graphical user interfaces for individual users to reduce visual search time. Little research, however, has been directed at understanding the factors which cause approaches to personalization to have positive effects at one time and negative ones at others. Approach: The study reported here investigated empirically the effects of content size on 5 different personalized menu types: Adaptable, adaptive split, adaptive/adaptable highlighted, adaptive/adaptable minimized and mixed-initiative menus. More specifically, it compared the usability of these five types with regard to task accomplishment time and frequency of error-occurrence. In order to carry out this comparative investigation, we conducted two independent experiments, on small menus (17 items) and large ones (29 items) respectively. These were tested dependently using 30 subjects each. Results: Results showed that the adaptable type was surprisingly the most efficient overall of the small menus and the least efficient of the large ones. Conclusion: Conversely, the minimized type was the slowest of the small menus and the fastest of the large ones. Finally, errors were reduced in adaptable and minimized small menus by 50 and 62% respectively, whilst being increased in the large adaptable one.