TREE TESTING TO EVALUATE NAVIGATION IN UX DESIGN

TREE TESTING

No online business would want to lose revenue because users can’t find the product they were looking for. No online business would want to lose revenue because users perceive the menu structure as confusing. Whether you are in the role to specify Information Architecture (IA), Usability Specialist or a UX / Interaction Designer for an online product, you would not want loss of revenue either. The design of a website or app navigation has a considerable impact on business success.

In allowing users to efficiently complete their goal on your website or app, navigation hierarchy needs to be well thought of and user validated. Specially those websites offering a hundreds and thousands of products and information, for instance, Retail, Telco, Insurance, hospitals, government services, etc. a poorly defined navigation hierarchy and confusing product categorisation could mean losing the most forgiving of customers. The business bottom-line could be impacted, thus handing over an advantage to the competitors. That is why, repeated user evaluations of your menu hierarchy and site navigation is so very important.

While qualitative study with users from your target audience would provide you with reasoning to specify first feel categorisation and navigation, backing up those with a quantitative results shall help you make further necessary adjustments. That is where, the Usability testing tools and techniques like Card Sorting and Tree Testing come in handy.

Card sorting is the first step in building information architecture (IA) for categorisation aka grouping of items or products. In Card sorting, each product is represented by a Card. Labelling of categories and subcategories is also covered in this step. You can make use of Closed or Open Card sort, the key difference being in Closed Card sort, names / labels of categories are predefined. Contrary to that, in an Open Card sort, users are required to specify a name for the (sub) categories. The outcome of a Card sorting study is a structure in which your content should be organized and labelled.

As the subsequent step, evaluation of the menu structure or information hierarchy that you have created via card sorting should take place. Placement of products is evaluated in this step using Tree Testing tool. Tree Testing helps to match the placement of products under one or more (sub) categories with user expectations. Typically in a Tree Test, users are shown a bare-bone menu hierarchy which is navigable using mouse clicks or taps, in case of a mobile device. The menu without any style sheets and pleasing aesthetics helps to eliminate variables from your study and to some extent, brings back the focus of user testers on findability of products.

Peter Harville, the author of famous book Information Architecture for the World Wide Web says:

“Findability precedes usability. In the alphabet and on the Web. You can’t use what you can’t find.”

Users are presented with Tasks to find a product in the given menu hierarchy and are asked to indicate when they find the specific item. The ideal outcome of each Task is that users can find the item exactly where you expected them to be – however, that may not be the case. You might see the users trying to navigate back and forth into (sub) categories, trying to find an item. In Tree Testing tool, each step of the user is captured and a summary of navigation is prepared for later analysis. Based on the analysis across users, following can be determined:

  • are users are able to find an item or give up?
  • is an item available when users expect it to be available?
  • do the users directly reach the location you expected them to find that item?
  • do the users expect the item to be available at multiple locations?
  • what percentage of users were successful to find an item?
  • how much time was taken to find an item?

There are a few steps in defining a Tree Test. First of all, a basic text structure of the menu hierarchy is prepared in the tool itself or alternatively via uploading of a Text, Comma Separated file. This tree structure has all the categories and subcategories of your menu tree. In case you have more than one version of menu hierarchy and want to compare the findability, you can do so via separate Tasks.

 

After the menu tree is created in the Tree Testing tool, you need to define Tasks for your user testers. Each Task has a goal to accomplish related to finding an item in a given tree. Tasks must be carefully written because in a remote setting, a potential ambiguity or mis-interpretation could make a significant difference to the outcome. The tool has built in basic instructions to the user Testers who should be provided with a URL to take the Test in a browser. As users take the Test, they are presented with the menu tree. The Tree can be clicked through to navigate. Users indicate where they’d find an item in a given menu tree. After indicating that, users proceed to next Task in the Tree test.

 

The data collected is shown in the online reports for easy analysis. You can analyse the data consolidated by Tasks. Time to completion, most-probable placements to find a product, directness and success-rates are key parameters that further inform your decision making about the Information hierarchy. For each individual user testers, the path and time taken for every Task are shown, allowing you to further investigate any unique navigation patterns based on demographics.


There are valuable advantages to using remote usability testing techniques like Tree testing and Card sorting. Tree testing evaluates the labelling of the (sub) categories – and that is why is is also called ‘Reverse card sort’. These remote tests can save a lot of costs in the Design budget because the preparation, exploration and optimisation of menus hierarchy and labels is fast and inexpensive. They avoid repetitive design and development and you do not need high fidelity graphical artefacts to perform this kind of Usability testing. Tree Testing can be done even before you make your first set of wireframes.

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