The information or data for Web page design that is useful, in particular, to older adults was provided in this study. The proper design of site map is necessary to enhance the usability and reduce the number of getting lost in Web navigation especially for older adults. However, no design guideline on what site map is proper exists. The usability of six types of site maps was compared as a function of age.
The six types of site maps included (1) vertical tree
type, (2) horizontal tree type (A), (3) horizontal tree
type (B), (4) table type, (5) radial type, and (6)
itemized type. The usability was evaluated using search time, subjective rating of usability, and eye movement characteristics (fixation duration and fixation number). The age affected the evaluation measures. The horizontal type (B) was found to lead to faster search time and fewer fixation numbers. Moreover, this type of site map was found to make the difference of search time, fixation number, and
fixation duration between young and older adults smaller. The result indicated that the vertical arrangement of site map, especially horizontal type (B) was proper for both young and older adults, and this should be incorporated into the Web page design guidelines. The results can be utilized as a universal design guideline for providing a site map that is friendly to both young and older adults.