An individual method can collect data about a set of specific constructs of user experience. For instance, usability testing is used to collect data about usability construct.[3] Methods also differ if they are to measure a momentary or episodic experience (i.e., assessing how a person feels about a specific interaction episode or after executing a task) or an experience over time, also known as an longitudinal experience. UXA methods can be classified in three categories: implicit, explicit and creative methods.