The first principle of usability says that you have to bring the program model in line with the user model.

This is called the program model, and it is The Law.

The popular choice is the best user model, and it's up to you to make the program model match it.

It's hard enough to make the program model conform to the user model when the models are simple.

Something has to give to bring the program model in line with the user model.

If your program model is nontrivial, it's probably not the user model.

The program model uses existing state universities in the five states for the first year of medical education.

Fueling interest in science: an after-school program model that works.

Within the broad parameters of the program model, these agencies played an important role in shaping implementation.

The way you make users understand your program model is with metaphors.