Results of this study indicate that the correlation between half-test scores over repeated splits, over persons, and over repeated testings resulting in different sets of observed scores, is given by Kuder-Richardson Formula 21. (RF)

Advocates the use of precision" rather than accuracy" in defining reliability. These terms are consistently differentiated in certain sciences. Review of psychological and measurement literature reveals, however, interchangeable usage of the terms in defining reliability. (Author/GS)

This paper describes and compares procedures for estimating the reliability of proficiency tests that are scored with latent structure models. Results suggest that the predictive estimate is the most accurate of the procedures. (Author/BW)

A more general method for calculating the Kappa measure of nominal rating agreement among multiple raters is presented. It can be used across a broad range of rating designs, including those in which raters vary with respect to their base rates and how many subjects they rate in common. (Author/BW)

Expressions involving optimal sign vectors are derived so as to yield two new applications. First, coefficient alpha for the sign-weighted composite is maximized in analogy to Lord's scale-independent solution with differential weights. Second, optimal sign vectors are used to define two groups of objects that are maximally distinct. (Author/CTM)

A coefficient of inter-rater agreement is presented which describes the magnitude of observer agreement as the probability estimated under a quasi-independence model that responses from different observers will be in agreement. (Author/JKS)

Guilford's average interrater correlation coefficient is shown to be related to the Friedman Rank Sum statistic. Under the null hypothesis of zero correlation, the resultant distribution is known and the hypothesis can be tested. Large sample and tied score cases are also considered. An example from Guilford (1954) is presented. (Author)

The robustness of hypothesis tests for the correlation coefficient under varying conditions is discussed. The effects of violations of the assumptions of linearity, homoscedasticity, and kurtosis are examined. (JKS)