Explanatory model to describe school district prevalence rates for mental retardation and learning disabilities.

Data reports from South Carolina's 92 independent school districts were used to calculate prevalence rates of mental retardation and learning disabilities among school-age children. These prevalence rates were 41.66/1,000 children enrolled for mental retardation and 33.21/1,000 children enrolled for learning disabilities. The 1980-1981 school year was selected because this was the last year in which disaggregated reports were submitted for placement in educable mental handicap (EMH), trainable mental handicap (TMH), and profound mental handicap (PMH) programs. Exploratory factor analysis and multiple regression analysis were used to explain school district prevalence rates of categorization of children into programs for mental retardation and learning disabilities. Results show that community SES and tax inputs explain 39% of the variation in prevalence rates and that these factors affect rates indirectly.