Health and Retirement Survey (HRS) and NHIS both oversample Hispanics and blacks, and the NHANES oversamples blacks and Mexican Americans). But samples are often not large enough to produce reliable estimates for smaller racial groups—Asians, Native Hawaiians and Pacific Islanders, Alaska Natives and American Indians. An exception is the Hispanic Health and Nutrition Examination Survey (Hispanic HANES), conducted from 1982 to 1984 for three Hispanic subgroups, Cubans, Puerto Ricans, and Mexicans. The examination of differences in health status among Hispanic subgroups and among non-Hispanic whites and blacks and Hispanics was made possible with this survey.
Special efforts, like the Hispanic HANES, are often required to obtain adequate coverage and sample size for specific subgroups. A survey, unlike administrative records, affords the researcher more control over the populations that are covered (although limitations in survey methods may limit coverage). But with limited resources for data collection, it is not always possible to conduct special surveys with the same frequency as those conducted for the nationally representative populations. Thus, which populations are covered in surveys is determined mainly by resources and other government priorities (e.g., the need to obtain answers to specific policy questions) rather than by limitations inherent to the data collection methods and processes.
Data collected through federal and state health programs or through the operations of health care providers (e.g., hospitals) are often used to measure and understand health status and health care utilization. Examples of administrative data systems include the Medicare Enrollment Database, which represents enrollees since 1966, and the federal Healthcare Cost Utilization Project, which collects hospital discharge abstracts in a uniform way from 28 state data organizations. These administrative data sets are more often used for their information on health care utilization rather than on health status, as measures of the latter are not usually collected as part of the administrative process. Administrative data are also used to measure disease incidence; for example, the CDC maintains a number of disease surveillance reporting systems to which hospitals, labs, clinics, and other health care institutions submit information on disease incidence (for example, bacterial meningitis, HIV/AIDS, food-borne illnesses).
Administrative data are collected to fulfill the particular purposes of a program or administrative process. Therefore, unlike survey data, where content is often (within budget and time constraints) under the control of the data collection agency, the content of administrative data is usually limited to the specific information needed for administrative objectives. For