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To determine the equivalence and relationship of Peabody and WISC scores in a retarded population, 49 students in a class for the educable retarded were tested. The Peabody IQ consistently over-estimated WISC Verbal, Performance, and Full Scale IQs. Intercorrelations berween IQs from the rwo tests were disappointingly low. A more cautious approach to use of the Peabody as a "substitute" measure for the WISC is suggested.Paralleling che expanding demand for psychological services has been an increasing reliance on brief measures designed to assess intellecnial level. At times, use of these shorter tests occurs despite evidence suggesting that scores on them are not equivalent to rhose obtained on the more time consuming tests for which they are substituted. Such seems to be the case with the Peabody Picture Vocabulary Test (Peabody), an instrumenr frequently used in lieu of the Wechsler Intelligence Scale for Children (WISC) in assessing mental retardation; and, the results of this sntdy are presented as a further cautionary note to chose who might use the Peabody In this fashion.Ss were 49 students er~olled in a special class for the educable retarded in Cheyenne, Wyoming. Age range was 7 ro 14 yr., with a mean of 11.1 All were tesced on both the Peabody and the WISC by school personnel. The significances of differences between mean Peabody IQs and the Verbal, Performance, and Full Scale IQs of the WISC were computed. Also, intercorrelations among IQs were determined.From Table 11, it is apparent that the Peabody IQ consistently over-estimates WISC IQs for our sample. Mean WISC IQs for Full, Verbal, and Performance Scales were 68.31, 69.02, and 73.06, respectively, the Full and Verbal Scales being significantly different from the mean Peabody I Q of 74.94. This result agrees with the three reported Peabody-WISC studies of retarded Ss that note at least one WISC IQ score

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