A model was developed for estimating individuals' true changes on test scores using the additional information provided by an auxiliary variable correlated with a trait being measured. This provides an improved and more precise estimate when compared with simple difference scores. It involves the reliability of "X" scores only. (SLD)

Single sample approximations are considered for the cross-validation coefficient in the analysis of covariance structures. Results of a random sampling experiment--using data from ability tests administered to high school students (sample sizes 100, 400, and 800)--illustrate the coefficient and adjustment for predictive validity. (SLD)

The effectiveness of the freshman admissions prediction equation (FAPE) at the University of Georgia (Athens) was studied, using data for 3,378 freshman (1,490 males and 1,888 females) in 1987-88. For the 1987-88 data, a previous (1982) prediction equation functioned poorly in terms of predictive accuracy. New prediction models were constructed…