Tree testing can be both qualitative and quantitative, depending on whether you're looking for formative or summative evaluation. Qualitative tree testing focuses on early-stage feedback and iterative improvement. It's ideal at the start of a project when you need to refine your information architecture quickly without designing full layouts or content.

Like usability testing, qualitative tree testing involves a small number of participants and often uses moderated sessions. This allows facilitators to ask probing questions and understand participants' thought processes. It's excellent for gaining insights on how to improve navigation but isn't suited for gathering statistical data like success rates or time on task.