Concurrent or Retrospective Thinking Aloud in Usability Tests: A Meta-Analytic Review

Abstract

In usability tests, the users are commonly asked to think aloud to let the evaluator listen in on their thoughts. Two variants of this procedure involve that the users either think aloud while using the tested product (concurrent thinking aloud, CTA) or after using it (retrospective thinking aloud, RTA). This study reviews the studies that compare CTA and RTA to investigate what is gained and lost by using one or the other variant in a usability test. A total of 29 studies, reporting from 42 comparisons of CTA and RTA, matched the inclusion criteria and were included in the meta-analyses. The main differences are that for CTA task time is longer, but total time shorter, whereas for RTA the users verbalize more explanations, problem formulations, and design recommendations. In addition, CTA users probably experience the evaluator’s presence as less disturbing than RTA users do.