Web navigation structures in cellular phones: the depth/breadth trade-off issue

One can browse the web with a variety of devices, including hand-held devices such as the cellular phone. The small screen of those devices poses some serious usability issues, one of which is the appropriate hierarchy depth of the web site. In this study, we empirically examined whether a broad navigation structure, which was found to be superior in regular screen-size platforms, also has an advantage for a small-screen device such as the cellular phone where it may require more movements and scrolling between screens of the same hierarchical level. Navigation times and success rates were measured for two search tasks in a mock web site that was built in two versions: one with a broad navigation structure and the other with a deep structure. Both structures were tested with cellular phone emulation and a standard desktop personal computer (PC). Results indicate that performance was better with the broad navigation structure for both the cellular phone and the PC. In addition, performance was better with the PC as compared to the cellular phone, and this difference was pronounced in the broad structure. The results are discussed in terms of the impact of deviceindependent characteristics of the hierarchy depth along with the theoretical account of increased working memory load, confusion and disorientation associated more with deep structures. r 2004 Elsevier Ltd. All rights reserved.