A Review of Global Literature on Using Administrative Data to Estimate Prevalence of Intellectual and Developmental Disabilities.

As understanding of health deficits among people with intellectual and developmental disabilities (IDD) increases, concerns grow about how to develop comprehensive, sustainable surveillance systems to reliably monitor the health of this population over time. This study reviews literature from 12 countries in which retrospective administrative data have been used to estimate population-based prevalence of IDD, identifies promising practices in that literature, and discusses the feasibility of applying those promising practices to other countries. Administrative data sources can be used to identify the number of people with IDD (numerators) in the presence of population estimates from which people with IDD are drawn (denominators) for discrete geographic locations. Case ascertainment methods, age groupings, data years captured, and other methods vary, contributing to a wide variation in prevalence rates. Six methods are identified from five countries that appear to offer the greatest likelihood of expanded applications. Approaches in which administrative data collections are linked with other population-based data sources appear promising as a means of estimating the size and characteristics of populations living with IDD in defined geographic locations. They offer the potential for sustainability, timeliness, accuracy, and efficiency.