This report documents a computer program for simulation evaluation of item response theory (IRT) ability estimators. This Honeywell DPS version is a very slight modification of the program originally developed in FORTRAN-77 on a DEC VAX 11/780. The model of the world simulated by the program involves a unidimensional test in which the probability of a correct response is given by a trace line on a single dimension (ability). The appendices contain: (1) the program; (2) a sample of its main output file using four items and 100 simulated examinees at each of five ability levels; and (3) a program to graph the robust simulation results. (Author/BS)