This study was designed to determine how reliable and valid a Zone Comparison PDD test is when the same individuals are administered the same test on two different occasions. Seventy-two subjects were used in an analog mock crime study using a Zone Comparison test format. Thirty-six subjects were randomly assigned to "innocent" and thirty-six to "guilty" programmed conditions. In addition, each subject was assigned to either an "accurate", "inaccurate", or "no" feedback treatment group. The overall accuracy for Tests 1 and 2 was 67% and 61 % respectively. Excluding the inconclusive decisions, the accuracy for Test 1 was 94% and 88% for Test 2. Both Test results discriminated between guilty and innocent subjects. There were no significant differences: between the guilty subjects on Test 1 and Test 2; between the innocent subjects on Test I and Test 2; nor between the guilty and innocent subjects on Test 1. However, the accuracy for the guilty subjects on Test 2 was significantly different from the accuracy rate for innocent subjects on Test 2. There was no significant difference for the innocent subjects between Test 1 and Test 2, and no significant differences between feedback groups.