The kappamax reliability index of domain-referenced tests is defined as the upper bound of kappa when all possibile cutoff scores are considered. Computational procedures for kappamax are described, as well as its approximation for long tests, based on Kuder-Richardson formula 21. The sampling error of kappamax, and the effects of test length and…

Three techniques for estimating Kuder Richardson reliability (KR20) coefficients for incomplete data are contrasted. The methods are: (1) Henderson's Method 1 (analysis of variance, or ANOVA); (2) Henderson's Method 3 (FITCO); and (3) Koch's method of symmetric sums (SYSUM). A Monte Carlo simulation was used to assess the precision of the three…

Assuming that the density p of the true ability theta in the binomial test score model is continuous in the closed interval (0, 1), a Bernstein polynomial can be used to uniformly approximate p. Then via quadratic programming techniques, least-square estimates may be obtained for the coefficients defining the polynomial. The approximation, in turn…

Single administration (beta-binomial) estimates for the raw agreement index p and the corrected-for-chance kappa index in mastery testing are compared with those based on two test administrations in terms of estimation bias and sampling variability. Bias is about 2.5 percent for p and 10 percent for kappa. (Author/RL)