DIFFERENCES REQUIRED FOR SIGNIFICANCE BETWEEN WECHSLER VERBAL AND PERFORMANCE IQS AND WIAT SUBTESTS AND COMPOSITES - THE PREDICTED-ACHIEVEMENT METHOD

This paper provides tables of critical values for determining statistically significant discrepancies between Wechsler Verbal/Performance IQ and WIAT subtest and composite scores based on a predicted-achievement method. It is recommended that these tables be used when a statistically significant and diagnostically meaningful Verbal IQ-Performance IQ discrepancy exists rendering either of these IQs a better estimate of a student's ability than the Full Scale IQ. Issues regarding the use of discrepancy formulas in the assessment and diagnosis of learning disabilities are discussed, and basic considerations for using the critical values tables are provided.