Purpose of this paper is to provide an alternative formulation which allows for the model parameters to be determined given the structural specification of zero mean error and independence among errors for different items and between errors and true scores. (Authors)

To resolve a recent controversy between Klein and Cleary and Levy, a model for dichotomous congeneric items is presented which has mean errors of zero, dichotomous true scores that are uncorrelated with errors, and errors that are mutually uncorrelated. (Author)

Given multiple independent measures of an underlying true factor and information on group membership, it is possible to compute a set of observed group means for each measure. Given at least three tests, these sets of means may be used to compute the reliability of the means for each test. The procedure for estimating true scores from the…

The general problem of using group status to estimate true scores given multiple measures is considered in this paper. (Authors)

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…