Usability of Websites

Abstract

Due to its reach, acceptance and capability to share information, the World Wide Web has become in an important tool for business. Millions of websites have been developed and so inherently we can come across every kind of website from easy to hard-to-use. There are some so-called usability criteria, which should be respected by web designers in order to make websites useful. Using a multicriteria decision making approach, we evaluate the performance, based on 7 usability criteria, of 5 websites from which one can buy books online. The complexity of multicriteria decision making is based on the fact that those multiple criteria are often contradicting with each other, and so a solution that optimises every criterion simultaneously, or an ideal solution, is generally unfeasible. In this situation making a decision implies giving an answer which without being optimal is still satisfactory. Considering usability as a subjective matter, we use two well-known methodologies that deal with this issue: Analytic Hierarchy Process (AHP) and PROMETHEE. Based on pairwise comparison matrices AHP transforms subjective judgements into quantified ratios of importance. PROMETHEE relates the preference of a decision maker with specially defined criterion functions. We analyse deeply the mathematical background behind AHP