Norm-referenced test interpretation in the diagnostic process

This study examines the extent to which norm-referenced tests can assist in addressing two independent clinical questions within the diagnostic process: "Is there a language impairment?" and "What are the specific areas of deficit?" Children's performance on two tests, the Test for Examining Expressive Morphology and the Patterned Elicitation Syntax Test, was examined from the perspective of each question. For the first question, a discriminant analysis using 40 preschool children (20 with specific language impairment [SLI], and 20 with normally developing language) revealed 90% sensitivity and 95% specificity for each test. For the second question, an item analysis revealed inconsistent pass/fail rates and low point-to-point agreement for the performance of children with SLI on items targeting the same morphosyntactic structure across tests. Given their high discriminant capacity, but inconsistent item-level performance, the results demonstrate that norm-referenced tests can be appropriate diagnostic tools for one diagnostic purpose but inappropriate for addressing another.