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• We ask the participant to do the tree test (using the testing tool) and encourage them to “think aloud” as they go.
  
  
• If they struggle to find a correct answer, we ask neutral questions to find out why they’re having trouble (“Tell me what you’re thinking now…tell me more about that…” and so forth).
  
  
• While not every participant will have trouble with the tasks we’re concentrating on, we hope to get a few who do, so we can find the cause of the problem.
  
  

For more handy tips on testing in-person, see Nick Bowmast’s short article.

Recording results

Another way to see why participants are making puzzling choices is to employ a remote usability-testing tool that records a screencast of the user's session. (UserTesting.com and TryMyUI.com are popular examples.)

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See this UserTesting.com blog post for an example of how recording remote sessions helped the author understand what needed fixing in their tree test.

•  manual recording of paper tests
•  see Nick's tips in article

For more tips on testing in-person, see Nick Bowmast’s short article. 

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Next: Closing the test