Determining whether score distributions differ on two or more test forms administered to samples of examinees from a single population is explored using three statistical tests using loglinear models. Examples are presented of applying tests of distribution differences to decide if equating is needed for alternative forms of a test. (SLD)

Examined the degree to which coefficient alpha is affected by including items with different distribution shapes within a unidimensional scale. Computer simulation results indicate that reliability does not increase dramatically as a result of using differentially shaped items within a scale. Discusses implications for test construction. (SLD)

An evolved form of the Edwards and Beckworth (1989) model for probability selection for Scholastic Achievement Test takers using truncated normal distributions is presented. It is shown that the arguments of Holland and Wainer are not sufficient to reject this model. (SLD)

The recommendation that the reliability of multiple-choice tests will be enhanced if the distribution of item difficulties is concentrated at approximately 0.50 is reinforced and extended in this article by viewing the 0/1 item scoring as a dichotomization of an underlying normally distributed ability score. (SLD)

The adequacy of linking statewide standardized test results to the National Assessment of Educational Progress by using equipercentile equating procedures was investigated using statewide mathematics data from four states. Results suggest that the linkings are not sufficiently trustworthy to make comparisons based on the tails of the distribution.…

Changes in information retention resulting from changes in reliability and number of intervals in scale construction were studied to provide quantitative information to help in decisions about choosing intervals. Information retention reached a maximum when the number of intervals was about 8 or more and reliability was near 1.0. (SLD)