ABSTRACT
The Rasch model (Rasch, 1960,1966a,b) is widely used and highly praised by some researchers but criticized by others who prefer more highly parameterized models for item response data. The reason behind both of these conflicting viewpoints is that the Rasch model can be derived from a small number of simple assumptions. Proponents say these assumptions form a mathematically elegant foundation of the model, while opponents say they are rather restrictive.
