A derivation of a formula for the stability coefficient is presented and discussed in terms of test reliability over time. (PR)

Two fundamental problems in mental test theory are to estimate true score and to estimate the amount of error when testing an examinee. In this report, three probability models which characterize a single test item in terms of a population of examinees are described. How these models may be modified to characterize a single examinee in terms of an…

Performance testing often entails the usage of expensive, time-consuming measures in the quest for determining the level of performance on some desired behavior. It is concluded that a generalizability theory approach to dealing with departures from reality in testing can aid in the establishment of empirically-based choices of measurement…

Omitted items cannot properly be treated as wrong when estimating ability and item parameters. A convenient method for utilizing the information provided by omissions is presented. Theoretical and empirical justifications are presented for the estimates obtained by the new method. (Author)

Forming a sequence covering the various aspects of the simplex model, four articles are presented here under the following titles: "A Simplex Model for Analyzing Academic Growth", "Analyzing Ratings With Correlated Intrajudge Measurement Errors", "The Correlation of States With Gain", and "The Reliability of…