Employing think-aloud protocols and constructive interaction to test the usability of online library catalogues: a methodological comparison

This paper describes a comparative study of three usability test approaches: concurrent thinkaloud protocols, retrospective think-aloud protocols, and constructive interaction. These three methods were compared by means of an evaluation of an online library catalogue, which involved four points of comparison: number and type of usability problems detected; relevance of the problems detected; overall task performance; and participant experiences. The results of the study showed that there were only few significant differences between the usability test approaches, mainly with respect to manner of problem detecting, task performance and participant experience. For the most part, the usability methods proved very much comparable, revealing similar numbers and types of problems that were equally relevant. Taking some practical aspects into account, a case can be made for preferring the concurrent think-aloud protocols over the other two methods. q 2004 Elsevier B.V. All rights reserved.