Tree Testing

Share on facebook
Share on google
Share on twitter
Share on linkedin

Tree testing is a usability technique for evaluating the findability of topics. A tree test evaluates a hierarchical category structure or tree. Tree testing is done on a simplified text version of your content – without the influence of navigation aids and visual design.

Tree testing can be used for websites, intranets, mobile UI, apps, games, enterprise solutions, kiosks, automotive displays, fast food electronic menu – anything that has a menu.

In a typical tree test:

  1. The participant is given a “find it” task (e.g., “Look for men’s belts under $25”).
  2. They are shown a text list of the top-level topics of your menu.
  3. They choose a heading and are then shown a list of subtopics.
  4. They continue choosing (moving down through the tree, backtracking if necessary) until they find a topic that satisfies the task (or until they give up).
  5. They do several tasks in this manner, starting each task back at the top of the tree.
  6. Once several participants have completed the test, the results are analyzed.

Tree testing analysis typically tries to answer these questions:

  • Could participants successfully find particular items in the tree?
  • Could they find those items directly, without having to backtrack?
  • If they couldn’t find items, where did they go astray?
  • Could they choose between topics quickly, without having to think too much?
  • Overall, which parts of the tree worked well, and which fell down?

Tree testing was originally done using index cards but now,they are typically conducted using specialized software such as Treejack and UserZoom.

“Prime time for tree testing is early in the design phase,once we’ve done enough research to feel we have a good handle on our audiences,their background, and their needs.” Accordingto Dave O’Brien.

According to Dave, “We start creating drafts of new structures… after we decide which content we will be adding, updating, or deleting. While content is always a moving target, it really helps to have most of it identified before trying to design a structure for it.”

This work on content and structure can be done in parallel with conceptual design, but usually comes before more detailed work such as layout, fine-grained interactions, and visual design.

From your research, you should have several ideas about what to change (and what not to) in a new tree – not just grouping but labeling too. It’s typical to rough out two to five different trees down to the second or third level.

In a perfect world, you would keep testing until you had a perfect tree, but there is never time or budget enough for that. Do as much testing as time and budget allows. The more testing you do the bigger the return on investments for your customers and, ultimately, your organization.