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Before tree testing became established, closed card sorts were a popular way to evaluate a site structure.

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• Most closed sorts only test a single set of groups, which only represent a single level of the tree (usually the top level). Tree testing evaluates the full depth of the tree.
  
  
• Closed sorts are essentially a filing exercise (“Where would you put this topic?”). While this is similar to browsing a website, it’s doesn’t mimic the act of browsing as well as tree testing does.
  
  
• Tree-test results are easier to analyse analyze than closed-card-sort results (as we’ll see in Chapter ~12 - Analyzing results).
  
  
  

Usability testing, whether in person or using remote tools, is a powerful technique, but it differs in some major ways from tree testing:

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