During the past 30 years, and particularly during the last 15 years, a variety of validity and reliability studies have been conducted to determine the accuracy and consistency of psychophysiological detection of deception PDD tests and their ability to discriminate between innocent and guilty subjects. A total of 72 subjects were used in an analog mock crime study that used a Zone Comparison test format. Thirty-six subjects were randomly assigned to "innocent" and 36 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 percent and 61 percent respectively. Excluding the inconclusive decisions, the accuracy for test 1 was 94 percent and 88 percent 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 1 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. 6 tables and 36 references