With the rapid increase in the U.S. elderly (65+) and oldest-old (85+) populations, considerable concern has emerged over the amount of future acute and long-term care (LTC) services that will be required by that population, and of the nature of the mixture of federal, state and private programs necessary to respond to that need. One of the areas of service needs with the projected greatest rate of growth is that for LTC services. The National Nursing Home Surveys (NNHS) conducted by the National Center for Health Statistics in 1963, 1969, 1973, 1977 and, most recently, 1985 (with a follow-up in 1987) have provided considerable information on the institutional component of LTC services. More recently, because of the rapid growth of the elderly and oldest-old populations, considerable interest has emerged in home LTC options, both because of concern about the economics of institutional care and because of humanitarian concern about the level of dependency and quality of life in many LTC institutions. Until the advent of the National Long Term Care Survey (NLTCS) there was no major nationally representative survey with specially designed instrumentation that dealt explicitly both with the health and functional problems of the community dwelling disabled elderly, the home LTC options (both formal and informal) available to meet those problems, and the ability to substitute, for a specific target population, home and institutional care. The 1982 NLTCS filled this gap in our knowledge and provided considerable information on which both to plan the nature of required services and to develop private insurance products to pay for such services. The 1984 NLTCS provided a basis upon which to examine changes in the home LTC populations and to examine the trajectory of service needs at the individual level.
The 1982 and 1984 NLTCS are detailed household surveys of persons aged 65 and over who manifest some chronic (i.e., 90 days +) Activity of Daily Living (ADL) or Instrumental Activity of Daily Living (IADL) impairment. The sample for the surveys was drawn using a two-stage procedure. In 1982, 36,000 names were drawn from the Health Insurance Master file. These persons were then screened by either telephone or personal visit to see if they manifested an ADL or IADL impairment of 90 days duration (or which was anticipated to last at least 90 days). When the screen identified a person living in the community with a chronic impairment, a detailed household interview was conducted which gathered information on medical status (diag- noses), functional status (presence of ADL, IADL or other functional impairments and equipment or caregivers utilized by the person to deal with his impairments), income and assets, health service use, use of federal services, housing and living arrangements. Of particular note in the survey were detailed questions on the number and type of informal caregivers. Institutionalized persons were not interviewed in 1982.
In 1984, a different sampling procedure was utilized. First, all persons who reported chronic disability on the screener or who were screener-noninterviewed due to institutionalization and who survived to 1984 were interviewed regardless of their 1984 functional status. Second, from the original 25,541 persons who did not report functional impairments in 1982 (and who were not institutionalized), a random sample of 47% (~12,100 persons) was drawn and subjected to the same screening procedure as in 1982. Another difference from 1982 was that 5,000 persons who became 65 between 1982 and 1984 were screened so that, in addition to having a longitudinally followed sample in 1984, the full cross-section of persons aged 65 and over in 1984 could be evaluated. In addition, persons who were in institutions in 1984 were interviewed with a specially designed instrument containing a number of questions on institutional use in the interim period and the sources of payment for those services. The interview instrument used for the community population was nearly identical in 1984 to that used in 1982. A final major difference between the 1982 and 1984 surveys was that a "next of kin" interview was conducted for persons who died between 1982 and 1984. This interview collected extensive data on the medical service use and expenditures surrounding death.
These surveys conducted in 1982 and 1984 cannot be fully exploited without considering their linkage to another important data source--Medicare Part A bill files from 1980 to 1985 on Medicare reimbursed hospitalization, home health services and skilled nursing facility use. These files contain bills for individual service episodes and provide a continuous history of the exact date of service use and the amounts reimbursed by Medicare for those services. Each bill in this interval is linked to the corresponding sample person who participated in either the 1982 or 1984 survey.
The dual cross-sectional and longitudinal nature of the 1982 and 1984 NLTCS and the linked Medicare service use files allow us to analyze a broad range of questions. First, they provide an impressive array of data on the community dwelling chronically disabled elderly, a population group at high risk of both extensive acute and LTC service needs. These data can help us estimate the need for LTC services, the actuarial basis of, and markets for, LTC insurance products, the role of "spend-down" for Medicaid qualification for LTC benefits, and the impact of informal caregivers on meeting the national need for LTC services.
In addition to describing the social, economic, functional and health status characteristics of a large (~5 million persons) population group at high risk for significant Medicaid and Medicare services (and for the development of private insurance options to provide parts of those services), the data files provide considerable information on the pattern of utilization and outcome of Medicare Part A (and potentially Medicare Part B) services. That is, the continuous time Medicare service history of individuals whose detailed health and functional characteristics have been determined from the surveys is available. This linkage can allow questions to be examined such as the substitution of home health and skilled nursing facility (SNF) services for acute hospitalization after the introduction of the prospective payment system (PPS) in order to assess how the reduction of the rate of hospitalization and the shortening of hospital LOS affected the nature of the use of these other service options. This can be used to evaluate the impact of such Medicare changes and to design changes, as necessary, in the provision of hospital, home health and SNF services by Medicare.
A third major area where these data can be important is in the study of changes, both for the individual and for the aggregate, in terms of health and functional status. Because of limitations on the availability of longitudinal data, the design of service and insurance options has been constrained. The availability of large amounts of nationally representative data on long term (two-year changes) in health, functional, economic, and social status is an important and unique feature of this data set.
A fourth major use of this data set is to help provide national estimates of LTC service needs by combining national distributions of functional limitations from the survey with very detailed data from select populations in a wide variety of LTC demonstration projects and waivered programs. That is, detailed data on Medicaid and private payment for LTC services are available in the demonstration projects along with data on the effects of those services (and modifications of those services) on a wide variety of social and health outcomes. The problem is to extrapolate those findings from the multiple, local select populations in the demonstrations to the national population. Because the instrumentation of the NLTCS has many measures in common with many of the demonstration projects, there is a lot of information on which to base the extrapolation.
In this introduction we have very briefly reviewed the rationale, structure, content and some potential areas of application of the 1982-1984 NLTCS and linked Medicare files. In subsequent sections we will explore specific technical issues concerning the quality of the survey data and its analysis in more detail.