National standardization of the Auditory Discrimination Test: normative and reliability results

The Auditory Discrimination Test (ADT), which consists of two alternate forms (Forms 1A and 2A), has been used extensively in clinical, educational, and research settings for nearly 30 years. Until now, two major problems with the clinical and educational use of the ADT have been the lack of representative norms, and the somewhat restricted age range of the test. This article reports on a national standardization of the ADT, and an extension of this test downward for use with four year old children. The sample included over 1.800 children from public and private elementary and preschool settings who were selected from over 30 states across the country. The sample was stratified on the basis of geographic region, age, sex, ethnic background, parent's occupation, and community size. Results indicated developmental differences in auditory discrimination as assessed by the ADT, substantiating the utility of age level norms. In addition, internal consistency reliability was computed for all age levels on the ADT. A median reliability of.78 was found for ADT Form 1A, and.81 for ADT Form 2A, with higher reliabilities found at the younger ages. Overall, the results of this investigation suggest that the ADT is a useful measure of auditory discrimination in young children. Furthermore, the development of national, stratified norms provides renewed utility for the application of test results in norm-referenced decision situations.