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How To Specify the Participant Group Size for Usability Studies: A Practitioner’s Guide

Ritch Macefield

Journal of Usability Studies, Volume 5, Issue 1, Nov 2009, pp. 34 - 45

Article Contents


This article argues that specification of the participant group size for a usability study remains a matter for debate and should be influenced by the unique features and context of each particular study. Within these caveats, the advice presented in this article is summarized in Figure 1. This figure shows typical ranges of group size for the two common types of usability study discussed in this article. The solid areas may be considered as baseline ranges applicable to typical scenarios. The figure also shows how common drivers may influence the group size specification for these types of study.

Figure 1

Figure 1. Advice summary


I thank the following usability practitioners for their excellent feedback and suggestions when authoring this article:


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