PROBLEM Forms I and I1 of the Stencils Tests have been found valuable in the study of schizophrenic thought (l, 2). This study explored the utility of a shortened version of Form I to estimate (a) mental efficiency as determined by the use of the mental age norms originally recommended for the test, and (b) the level of item difficulty a t which the individual might perform when the influence of temporary inefficiencies is controlled. The level of item difficulty should be an aid in evaluating intellectual capacity in children and chronic schizophrenics, many of whom perform inconsistently on mental tests. METHODThe Ss were 24 retarded children (Mean age = 11.0 k 2.1), originally tested because of learning problems presented in school; 32 chronic schizophrenic adults (Mean age = 40 f 11) observed previously(2); and a developmental group of 41 children (Mean age = 9.0 k 1.9) plus 8 adults (Mean age = 43 k 15). Child outpatients were above the age of 5.5 years and generally had a diagnosis of adjustment reaction; adults, mildly neurotic or essentially normal. Some of the retarded children and all other Ss received brief forms@) of the WISC or WAIS Scales. In all cases, the sum of the weighted scores for the Arithmetic, Digit Span, Information and Similarities sub-tests of the WISC were converted into Wechsler Ranks as shown in Table 1. For adults, the Picture Completion was used in the place of the Similarities sub-test to determine WAIS scores. All weighted scores were determined from the normative tables provided for use with Ss at the age of 15.9 or 16.The order was rearranged so that the two-stencil items, 1, 3 and 2, were administered fist; then the more simple three-stencil items, 4, 5 and 7. (The results on developmental Ss showed that item 3 was passed more often than 2, and item 7 was passed more often than 6.) The more difficult three-stencil items, 6 , 9 and 12, were administered next; followed by the four-or-five-stencil items, 8, 10, 11, 14, 13, 15 and 16, in that order, then the most complex items, 16 to 20. Initial testing was terminated with three consecutive misses.Two types of comparisons were made. First, the raw Stencil score was compared with the estimated Stencil score. The raw score was the number of correct constructions on the first administration of the 20 items. The estimated score was determined from weighting Brief Form items (Table 1) passed initially. The easiest item at each Level was weighted 1 ; the second and third, 2. The sum of the weights on items passed initially on the Brief Form items was the estimated score.Secondly, Wechsler Ranks were compared with Stencil Ranks. The Stencil Rank was determined by items on the Brief Form which were passed initially or upon a readministration. When there was doubt whether an item was passed or failed by chance, the ability to perform on that item was explored until S demonstrated whether he could perform consistently. The criteria for Stencil Ranks are presented in Table 1. For example, a Rank of 9 would be earned when S passed two of item...
