After research, the designer uses the modeling of the users and their environments. User modeling or personas are composite archetypes based on behavior patterns uncovered during research. Personas provide designers a precise way of thinking and communicating about how groups of users behave, how they think, what they want to accomplish and why. Once created, personas help the designer to understand the users' goals in specific contexts, which is particularly useful during ideation and for validating design concepts. Other types of models include workflow models, artifact models, and physical models.