Journal Issue: Special Education for Students with Disabilities Volume 6 Number 1 Spring 1996
Comparison of OSEP Datawith Data from NationalSurveys
Various national surveys and studies including the Current Population Survey (CPS), the National Health Interview Survey Child Health Supplement (NHIS/CH), High School and Beyond, and the National Education Longitudinal Study of 1988 have all been used to supplement OSEP data in an attempt to better estimate the number of students with disabilities in the population.21 Because the criteria used to identify students with disabilities have varied across these data collection efforts, prevalence estimates from different sources may vary for largely technical reasons. With this important caveat in mind, Table 1 compares data based on parent reports of children with and receiving services for disabilities from the 1988 NHIS/CH and the 1992 CPS with OSEP data for corresponding years.
The 1988 NHIS/CH was a national survey of 17,110 children. Data collection was by in-person interviews with informed adults (usually mothers), and all data are based on the report of the adult respondent.22 Parents were asked a number of questions about whether the child ever had various kinds of disabilities and whether the child received services for the condition in the past 12 months.
The CPS is a large on-going population survey conducted by the Bureau of the Census. Data from this survey reported in Table 1 are from the 1992 October supplement to the CPS on school enrollment.23 The data reflect parental responses to a single question about whether children have ever had any of a list of 10 disabling conditions. The 10 conditions correspond to the 10 largest OSEP disability categories.
The selective comparisons of some of the larger categories in the national surveys and the OSEP data reveal several inconsistencies and do not yield generalizable conclusions. For 1988, parents in the NHIS/CH report a higher proportion of children in special education for learning disabilities and emotional problems than schools report in the 1988-89 OSEP data. Parents also reported substantially higher rates of children experiencing these problems than were being served at the time of the survey. In comparison, estimates of the proportion of children with selected disabilities based on parental reports in the 1992 CPS match the OSEP data fairly closely. There are, however, substantial differences in the proportion of children reported by parents to have disabilities in the 1988 and 1992 surveys. It seems improbable that the prevalence of disabilities could have changed so dramatically over the four years between 1988 and 1992. It is more likely that there are other factors, perhaps specific to the surveys themselves, that account for the substantial differences between 1988 and 1992.
Exploration of the many reasons the national survey data agree with the OSEP data in one year but not in another is beyond the scope of this short article. However, based on the comparisons presented in the table, it is reasonable to conclude that national surveys of parents probably cannot be relied upon as a means of obtaining accurate information about the prevalence of disabilities requiring special education.