Formalizing Design Guidelines of Legibility on Web Pages

Screen design of web pages is challenging because web pages contain lot of icons, consisting not only of texts with various fonts but also graphics with different sizes and content. The objectives for screen design of a web page can be either to provide aesthetic beauty, to convey complex information, to improve legibility, or some combination of the above. This study chooses to formalize design guidelines of legibility because information is becoming more and more complicated in web pages and hampering the efficiency of information searching. This study proposes six measurements of screen legibility: screen ratio of navigator to content, font size variety, variety of icon types, color contrast between background and foreground, content density, and number of alignment points. These six factors were then use to measure the legibility effectiveness of the startup page on four different yahoo.com sites. Combined with the results from a survey study, we concluded that all six factors were validated to be attributes with a significant and measurable impact on web site legibility.