The validity of an evaluation model for mastery testing applications was investigated. Three variables were tested in an experiment using 96 third grade subjects--amount of training, number of alternates in an item, and number of items. The concept hierarchy involved an orderly progression from a concept involving one relevant of three varying dimensions through two relevant of four varying dimensions (concept 2) to four relevant of six varying dimensions (concept 3). This established the basis for computing mastery evaluation cut rules on the basis of the model. Reliable differences occurred for training level and for concept difficulty, but not for test length or item types. The results of the validity analysis were, in general, favorable to the model. It is thus concluded that the proposed model is reasonably valid. This evidence could be used as a basis for a demonstration or experimental implementation of the model in an educational environment that uses mastery evaluation procedures. (DJ)