Once you've developed your site's new structure (or information architecture), it's smart to tree test it to ensure it will work for your customers before starting your design. Learn more about what tree testing is, how to conduct an effective test, and how to analyze your results.

What is a Tree Test?

Tree testing is technique for evaluating the findability of content within your information architecture. It is typically done after you have drafted a site structure (hopefully based on the results of a card sort).

In a typical tree test, participants are given a task and asked to navigate through a hierarchical list ("tree") of topics and subtopics to identify where they would complete it.

Conducting an Effective Tree Test

Here are some tips to help you plan your tree test:

  • Think about the purpose of your test. What do you hope to learn?
  • Decide how many participants you need. Aim for 30 to 50 participants at a minimum.
  • Limit the time it takes to complete the test to 10-15 minutes.
  • Recruit members of your actual audiences. We often advertise our tests via our website and/or through appropriate listservs.
  • Get the appropriate approvals. You'll need approval from the Web Governance Team (WGT) and the Office of Management and Budget (OMB). Learn more about getting the necessary approvals.

Personally Identifiable Information

Only collect Personally Identifiable Information (PII), such as email, phone number, or address, if you need it for analysis. Any PII you collect must be stored on a Department of Energy server that has been certified and accredited.

Setting Up Your Test in Treejack

Here are a few tricks to setting up your test in Treejack:

  • Cut and paste your final architecture into Treejack. Be sure your architecture is correctly indented to reflect relationships between topics before pasting it into Treejack.
  • Enter your scenarios and choose one or more correct answer choices for each scenario.
  • Randomize the scenarios to reduce biases introduced as participants learn the tree.
  • Allow participants to skip scenarios they wouldn't normally do or aren't sure about to keep your data more accurate.
  • Make a copy of your test before launch. Once the test is launched, revisions cannot be made.

Contact the EERE Web Usability Coordinator if you'd like to use Treejack to conduct your test. 

Pilot Testing Your Tree Test

Be sure to pilot your test with a few internal people who know your audience before you deploy it to your customers.

Getting Approval for Your Tree Test

All tree tests need approval from the Web Governance Team (WGT), and most will need Office of Management and Budget (OMB) approval as well.

Submit your test materials to the WGT for approval and schedule a meeting with them to review.

OMB approval is necessary for usability tests that collect information from 10 or more respondents from the general public. OMB approval is not required if tests are conducted internally among federal staff. Government contractors are not considered federal staff members.

Submit your test materials to OMB after you have received WGT approval..

Analyzing Your Results

When analyzing your data, try to assess:

  • How successful were participants in finding the right answer to each scenario?
  • How direct was the participants' path to finding the information? Did they have to backtrack?
  • If they weren't successful, where did they go astray?
  • Were they able to do the tasks quickly, without having to think too much?