While score comparability across test forms typically relies on common (or randomly equivalent) examinees or items, innovations in item formats, test delivery, and efforts to extend the range of score interpretation may require a special data collection before examinees or items can be used in this way--or may be incompatible with common examinee…

Two problems in the investigation of predictive bias in tests, the effect of unreliability of the predictors, and the effect of excluding a predictor from the regression equation on which there are preexisting group differences, are discussed. (Author)

Five indices are discussed that should logically discriminate between situations in which: (1) the linear equating method (LEM) adequately adjusts for difference between score distributions of two approximately parallel test forms; or (2) a method more complex than the linear equating method is needed. (RL)

The validity of a comparison of mean test scores for two groups and of a longitudinal comparison of means within each group is assessed. Using LISREL, factor analyses are used to test the hypotheses of similar factor patterns, equal units of measurement, and equal measurement accuracy between groups and across time. (Author/DWH)