UBC Theses and Dissertations
The effects of experience and test revision on the rate of practitioners’ clerical errors on the WISC-R and WISC-III Klassen, Robert Mark
The purpose of this study was to investigate the effect of test revision and examiner experience on the rate of examiner clerical error on the Wechsler Intelligence Scale for Children - Revised (WISC-R) and the Wechsler Intelligence Scale for Children - Third Edition (WISC-III). A total of seven school psychologists provided a sample of 252 protocols: 18 from each psychologist for the WISC-R, and 18 from each psychologist for the WISC-III. The errors tabulated consisted of clerical errors only, that is, addition of subtest raw and scaled scores, computation of chronological age, transformation from tables of raw score to scaled scores, and transformation of scaled scores to IQ scores. Clerical errors were found on 38% of WISC-R protocols, and 42% of WISC-III protocols. Errors caused by incorrect addition of raw scores were the most common error type. No significant difference was found between the two tests for any of the types of clerical errors. A positive but statistically non-significant correlation was found between examiners’ years of experience on the WISC-R and number of errors made. On the WISC-III only, a comparison was made between the clerical error rate at the beginning of usage of the test, and the clerical error rate in two time periods in the 12 months following the beginning of usage of the test. With overall errors, no significant difference was found between the three time periods. However, examiners made significantly more Full Scale IQ-changing errors at the beginning of WISC-III administration than they did in the third six-month time period. It was suggested that test publishers provide clear directions on the actual protocol to test users to help lower the rate of clerical errors. It was also suggested that because of the high rate of clerical errors at the beginning of the use of the WISC-III, practitioners need formal retraining on a test when it is revised.
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