" . . . 43 schizophrenic patients were tested and retested utilizing the methods of Reproduction, Verbal Estimation, and Operative Estimation. The intervals were of 5, 10, and 15 sec. duration, and they were presented both as filled and unfilled intervals." The intervals (filled or not with a buzzer sound) did not affect judgments by the 3 methods. "By Verbal Estimation intervals were consistently overestimated, but only the 5-sec. interval was overestimated by the other 2 methods. Reproduction gave the least consistent results. Both Verbal and Operative Estimation "can be regarded as measuring the same function inversely, since they have a high negative correlation." (PsycINFO Database Record (c) 2006 APA, all rights reserved)