"A comprehensive study on Validity and Reliability of Detection of Deception conducted by D.C. Raskin, G.H. Barland, and J.A. Podlesny (1978) for the National Institute of Law Enforcement and Criminal Justice that included fi eld studies and laboratory experiments concluded that the optimal score threshold using the Utah Zone Comparison Technique format was a fixed threshold of +/-6 which would result in an accuracy rate from 88 to 90 percent with an inconclusive rate of approximately 9 percent. Further, the study shows that as the scores increase, there is a moderate increase in accuracy reaching approximately 98 percent, particularly from +/-9 to +/-12, but at the expense of an increase in inconclusives. Furthermore, in the Matte, Reuss 1989a fi eld study, tables 10a1, 10a2, 10b1, 10b2 and 10c show that as the scores increase the probability of error decreases, hence an increase in accuracy. "(...)