The locus of so-called IQ test results in reading disabilities

It would appear the question of relevance of IQ in the assessment and remediation of children with RD is not quite the relevant question to ask, if only traditional intelligence tests are the focus. From the psychoeducational point of view of refining diagnosis, and from the administrative perspective of accountability, it would be helpful to accept a threshold of something like an IQ of 85 as the lower bound in defining learning or reading disabilities. A discrepancy from this threshold as derived from regression analysis or other more refined analyses and taking into account varying reliabilities, intercorrelations, and standard errors of measurement of different measuring instruments may constitute a learning or reading disability. How discrepant the aptitude-achievement should be to constitute a "significant" difference is a function of, among other factors, the material and human resources available to any particular school system. Leong (1987) has made suggestions for essentially a two-stage assessment leading to more refined diagnosis with the use of well-standardized group tests and teachers' estimates for the first stage (assessment) and more refined individual tests to diagnose those showing discrepant aptitude-learning performance in the border-zone. The rationale is that all those children requiring special services are so served and those in the uncertainty region must be carefully diagnosed so as to minimize so-called "misfits" in accordance with signal detection principles. It should be noted that the diagnosis of learning or reading disabilities can never be exact, even with the use of reliable and valid test instruments, and the "fuzzy set" approach should apply to the process (Horvath, Kass, & Ferrell, 1980).(ABSTRACT TRUNCATED AT 250 WORDS)