Multiple methods and the usability of interface prototypes: the complementarity of laboratory observation and focus groups

Recently, I used a focus group in a usability study of an interface prototype as a balance for a laboratory observation. The clients for this usability study wanted a sense of whether their interface was attractive to a range of users, whether the range of users understood the product, and whether the users could use the interface quickly; they also wanted user feedback on a list of potential features they could include in the next phase of development. Because of very limited resources available for the usability study, and because of the disparate questions the clients had, a focus group for some new users was used to supplement a laboratory observation and interview of other new users. This paper reports on what strengths and weaknesses these methods yielded as complementary approaches to testing the usability of interface prototypes.