By means of computer simulation of test responses, the reliability of item analysis data and the accuracy of equating were examined for hypothetical samples of 250, 500, 1000, and 2000 subjects for two tests with 20 equating items plus 60 additional items on the same scale. Birnbaum's three-parameter logistic model was used for the simulation. The equating procedure used was described as the Anchor Items Method, and the equations for this method are given. The results of the simulation are presented in tables showing the following data for all four sample sizes: correlations between known and estimated item parameters for all three parameters, and sums and means of absolute differences for differences (errors) for all three parameters. Also shown are means, standard deviations, and correlations for the a and b equating parameters. (CTM)