The dominant instructional model within special education, Differential Diagnosis-Prescriptive Teaching, involves the assessment of psycholinguistic and perceptual motor abilities that are presumed necessary for learning basic academic skills. Based on the differential pattern of ability strengths and weaknesses resulting from this assessment, individual remedial prescriptions are prescribed.In this article five assumptions underlying this model are identified. Also presented is a comprehensive review of research related to each assumption. The findings seriously challenge the model's validity and suggest that continued advocacy of the model cannot be justified. Children do not appear to profit from current applications of Differential DiagnosisPrescriptive Teaching.
DD-PT: A Critical Appraisal
2Differential Diagnosis-Prescriptive Teaching:
A Critical AppraisalThe term "differential diagnosis" refers to the process of assessing the learning characteristics of a child so that instruction can be matched to individual learning needs (Kirk & Kirk, 1971, p. 12; Kirk, 1972, p. 7). Although, in theory, this could include any procedure that attempts to delineate a child's specific strengths and weaknesses (Ysseldyke & Salvia, 1974), it has traditionally referred to those practices that attempt to diagnose abilities that presumably are prerequisite for or underlie academic learning (Mann, 1971;Ysseldyke, 1973). Such general psychological processes include auditory abilities (e.g., auditory discrimination and memory), visual abilities (e.g., visual discrimination and spatial relationships), cross sensory perceptual abilities (e.g., auditory-visual integration) and psycholinguistic abilities (e.g., auditory sequential memory and verbal expression). According to this model, failure to master basic academic skills, such as reading, may be traced to impairments in one or more of these underlying processes or abilities. To illustrate, a child who experiences failure in school tasks such as spelling phonetically irregular words, answering sequence questions based on material read, or copying sentences, may be found to suffer from an impairment in a basic process such as visual sequential memory (the ability to order a series of items so as to match a previously given model).
DD-PT: A Critical Appraisal
3The term "diagnostic-prescriptive teaching," often used in conjunction with Differential Diagnosis, refers to the practice of formulating instructional prescriptions on the basis of differential diagnostic results.These prescriptions generally take one of two forms. In one form differential diagnostic information is used to generate a program to directly remediate an underlying ability weakness. In a second form weak abilities are not remediated; rather, the focus is on academic targets, such as reading or math, for which instructional programs are devised that capitalize upon the child's pattern of underlying strengths and weaknesses, as identified in the course of diagnosis. An example of the former approach would be...