Classification procedures are common and useful in behavioral, educational, social, and managerial research. Supervised classification techniques such as discriminant function analysis assume training data are perfectly classified when estimating parameters or classifying. In contrast, unsupervised classification techniques such as finite mixture…

A replicable process for improving instruction through the consistent use of student data collected before, during, and after instruction is proposed. A rational analysis of different types of error rates (theoretical, base, posttest, instructional) and discrimination indices (base, posttest) leads to a set of rules for identifying test items and…