The development of an index reflecting the probability that the observed correspondence between multiple choice test responses of two examinees was due to chance in the absence of copying was previously reported. The present paper reports the implementation of a statistic requiring less restrictive underlying assumptions but more computation time and a related Bayesian procedure designed to adjust the standard error estimates to counteract the effect of the presence of a substantial proportion of cheaters in a sample. The Bayesian adjustment did reduce the bias; however, the original index appears to be the most accurate and least expensive in terms of processing cost. With either method, results suggest that cheaters may be conclusively identified when they copy more than 50 percent of their answers from anyone answering less than 90 percent of test items correctly. (BW)