Appropriate interpretation of assessment data requires an appreciation that tools are subject to measurement error. School psychologists recognize, at least on an intellectual level, that measures are imperfect--that test scores and other quantitative measures (e.g., rating scales, systematic behavioral observations) are best estimates of…

A total of 19 graduate students enrolled in a graduate course conducted 6 consecutive administrations of the Wechsler Intelligence Scale for Children, 4th edition (WISC-IV, Canadian version). Test protocols were examined to obtain data describing the frequency of examiner errors, including administration and scoring errors. Results identified 511…

No WISC-R IQ scale is immune to serious scoring errors. Inspection of the standard deviations reveals that the score an examinee receives for a given performance on WISC-R content can easily vary by six to eight IQ points. (Author)

The Wechsler Intelligence Scale for Children, and the revised form of that measure, were administered to a sample of sixth grade pupils. Although the correlation between measures was high, scores on the revised form were significantly lower. (JKS)