Model the User

This is an initial part of both the evaluation process and the design of the text itself. An understanding of user characteristics and variations should guide the design of a text by helping to match internal structures and external facilities to the user, by suggesting appropriate metaphors for learning, and by giving explicit motivation to crucial design decisions. User models also provide a framework for evaluation by giving a predictive interpretation to the design. They should identify basic user variables, as well as the social, organizational, and ergonomic context of these variables.