Sumn2a~y.--45 Ph.D. clinicians, with at least 4 yr. post-doctoral clinical experience, made a diagnostic judgment from the C-V-S Intelligence Scale protocols of 10 Ss in normal, retardate, organic, process, and reactive schizophrenic categories ( n = 5 0 ) , with judges grouped on the basis of number of subtests (1, 2, or all 3) and type of subtest information (various combinations of C, V, and S) used. Correct diagnose (validity) using 1, 2, or 3 subtests significantly exceeded chance. Contrary to the hypothesized relationship, diagnostic accuracy did not increase when the number of subtesrs to be judged was increased. Interjudge agreement (reliability) increased significantly as a function of increasing information. Methodological factors in studies assessing validity and reliability of clinical judgment were cited.The two factors that have received the most attention from researchers in the area of psychodiagnostic clinical judgment have been the validity and reliability of these judgments. In one particularly extensive series of judgmental stitdies (Hunt & Jones, 1962) these factors are encountered in the form of correctness of diagnosis and inrer-judge agreement. The present study investigates accuracy of diagnosis and inter-judge agreement as a function of varying the amount of information to be judged and as a function of the diagnostic categories being studied.The relationship between the amount of information presented to a judge and the correctness of his predicrion has rypically followed the approach of selectively adding or subtracting sources of information and then measuring the resultant increment or decrement in accoracy. Investigations by Kostlan ( 1954) and by Sines (1959) have indicated that accuracy can be increased as more data are made available to the jcdge. T o the contrary, however, Soskin ( 1959), Weiss ( 1963 ) , and others reported no increment in accuracy with increased amounts of information. For the most part, these studies varied amount of information by employing data such as biographical sketches, interviews, MMPI, and Rorschach protocols.