The two most common approaches to test information architecture are tree testing and card sorting. While both have overlapping benefits and can be used as complementing research methods, they’re typically used at slightly different stages in the research process:
Card sorting. Card sorting is a UX research method in which users organize topic cards into categories in a way that makes sense to them. This research activity is an important step to creating an intuitive information architecture (IA) and user experience. Card sorting is a good method for defining and testing new website architectures, where learnings can show how your users would categorize information.
Tree testing. This research method helps you evaluate the hierarchy and findability of topics in an app or website. Tree testing is a good way to test existing information architecture models and see if users can ultimately find what they’re looking for.
 To discover more about tree testing and card sorting, check out our What is UX Research Guide.