Usability testing is at its most effective when the people who participate in the user testing are ACTUAL users! This seems so simple that it's silly to talk about it. However, it's surprising how often this principle does not translate into real-life user testing.
For a research study to possess ecological validity, the methods, materials and setting of the study must approximate the real-life situation that is under investigation.
At the far end of the spectrum, we know that asking employees to "pretend" to be customers while they complete the usability test is an ineffective (and risky) substitute for the real user. This type of quick-and-dirty usability testing can provide false results, and can involve a significant amount of time and money to be spent on a concept or an interaction design that simply doesn't work for the real user.
A less-noticeable type of user substitution happens more often, when one participant is asked to play multiple roles. This is common when there are multiple user groups and there is not enough time and money to test individuals from every single user group. So, one participant is asked to complete 2 or 3 tasks that are relevant to them personally, and then they are given tasks for other user groups. Here are some examples: "Suppose you are a manager. What would you do now?" or "You are a truck driver, and you are looking for a map. Please show me where you would find that." In the latter instance, one participant said, "Well, I was looking over here, but then I remembered that I am a truck driver. I had forgotten." Hearing these comments is evidence you are asking the user to role-play, which will leave you with unreliable data regarding user behaviour and user needs with respect to your absent user group.
In a recent round of user testing, I was able to use actual material that the user group sees on a daily basis. The research was for a stock photography site, and the user groups were designers and researchers who spend their time on stock photograph sites, looking for specific photos. These individuals receive “creative briefs” from clients which are basic descriptions of the type of photo they want, and other supplementary information (such as other photos that approximate what they want, or a tagline if the assignment is an ad). A frequent user task involves sorting through various photos from stock sites to find ones they think fit the requirements. When testing with this user group, I was able to use these “creative briefs” in the user tasks – it was a task that this group of users performs on a daily basis, so their search behaviour and their interaction with the test system is almost identical to their real life scenarios ensuring results with a high-degree of validity.
This high degree of ecological validity is mostly applicable to traditional usability testing. When conducting walkthroughs with a prototype or testing conceptual ideas, there are often no “real-life” tasks since the product does not exist yet. But the more the proposed tasks resemble “real-life tasks” for “real-life users”, the more reliable the results that fuel the creation of a more usable and useful product
Brewer, M. (2000). Research Design and Issues of Validity. In Reis, H. and Judd, C. (eds) Handbook of Research Methods in Social and Personality Psychology. Cambridge: Cambridge University
About the Author