Four recent indices emphasizing the interrelationships of score distribution shape, modality, mean, and variance were investigated to determine the reliability of mastery tests. Attention was focused on the values of the indices when the cutoff score was near to or far from the modes of distribution. Five types of score distributions were examined: bill shaped; highly negatively skewed unimodal; bimodal with a stronger mode at the upper end; symmetric bimodal with modes well separated; and symmetric bimodal with modes near each other. Indices examined were based on: (1) Brennan and Kane's index of dependability; (2) Huynh's single administration estimate of the kappa coefficient of agreement; (3) the mean split-half coefficient of agreement, a revision of an earlier formulation by Marshall and Haertel; and (4) Subkoviak's single administration estimate of the coefficient of agreement. (Results are discussed and an explanation of symbols and formulas are appended.) (MH)