Studies have revealed significant problems in correctly scoring ambiguous verbal responses to test items on the Wechsler Intelligence Scale for Children-Revised (WISC-R). This study evaluated the effectiveness of an instructional design procedure developed to reduce examiner scoring errors on the WISC-R. Data concerning frequent sources of error on the WISC-R were obtained from 14 clinical psychology graduate students (pre-intervention group) enrolled in an Individual Intelligence Testing course. Remedial strategies were developed to clarify response categories and minimize errors due to carelessness. Strategies were used with 9 post-intervention students who took the course the following fall term. Pre- and post-intervention students completed the course and administered the WISC-R several times. A total of 98 pre-intervention and 63 post-intervention protocols were analyzed to determine the number and type of errors. Compared to the pre-intervention group, the post-intervention group had significantly fewer errors, with careless mathematical and clerical mistakes almost eliminated. Students continued to make mistakes, showing no improvement with practice in test administrations. A certain amount of difficulty in scoring may be inherent in the WISC-R test manual, and it may be advisable to incorporate examiner scoring errors into the WISC-R standard error of measurement. (Author/NB)