Conducting periodic surveys of specific subpopulations of policy interest, such as special education students, is an important way that disability data limitations are currently addressed. More than half of the 40 surveys reviewed for this report represent such surveys. The need for these types of surveys is driven by the specific information needs of particular agencies and the inability of general population surveys to identify or include in their samples sufficient numbers of particular individuals for which disability information is needed. Medicare beneficiaries, SSI and SSDI beneficiaries, nursing home residents, children, seniors, special education students, veterans, and prison/jail inmates are examples of subpopulations for which surveys have been conducted periodically in the past. Less frequent subpopulation survey efforts have focused on individuals with mental illness or intellectual disabilities, and homeless individuals. Subpopulations of particular interest to federal and state staff and for which disability data are thought to be inadequate are listed in Chapter II (Section C.2).
Most subpopulation surveys focus on those in a population, rather than those transitioning into or out of the subpopulation, such as applicants. The NLTS surveys are important examples of such a survey; the NLTS population is special education students who are at an age where they are about to transition out of the public school system into adulthood. As noted previously, however, state and federal agency staff indicated there is an information gap surrounding transitions from education to employment, changes in residences, or from institutional to noninstitutionalsettings (and vice versa), entry to and exit from public programs, and across changes in health care systems. Hence, adding special surveys that start with transitioning populations might be of considerable value. A survey focused on transitions would seek to capture people before and after they belong to a given subpopulation. In terms of program participation, potential survey respondents could be identified at the point of program application. The survey could ask retrospective questions at that point, thenfollow these individuals as they become enrolled in the program and continue to follow them after program exit. This would also create an opportunity to survey and compare accepted and rejected program applicants.