IQ variability in children with SLI: implications for use of cognitive referencing in determining SLI.

The practice of cognitive referencing assumes that IQ scores can be used as a measure of intellectual potential from which language scores may deviate. To test the validity of this assumption the WISC scores of children with specific language impairment were compared over time. The variability of WISC scores from children with SLI from their initial evaluation and from the federally-mandated three year re-evaluation was analyzed. Significant differences in the performance scale scores were found. This indicates that the IQ scores of these children are more properly interpreted as reflecting current abilities rather than potential for language learning. This further calls into question the practice of cognitive referencing as a method of determining the presence of a language impairment, eligibility for services, and the service delivery model for which a child qualifies.