Measuring web usability using item response theory: Principles, features and opportunities

Usability is considered a critical issue on the web that determines either the success or the failure of a company. Thus, the evaluation of usability has gained substantial attention. However, most current tools for usability evaluation have some limitations, such as excessive generality and a lack of reliability and validity. The present work proposes the construction of a tool to measure usability in e-commerce websites using item response theory (IRT). While usability issues have only been considered in theoretical or empirical contexts, in this study, we discuss them from a mathematical point of view using IRT. In particular, we develop a standardised scale to measure usability in e-commerce websites. This study opens a new field of research in the ergonomics of interfaces with respect to the development of scales using IRT.

► We propose the construction of a tool to measure usability in e-commerce websites.
► We present a method to build scale in e-commerce using the Item Response Theory.
► We present a scale in which website and items are positioned on the same continuum.
► The study showed the importance of navigational issues for the usability of a website.