We briefly described in the introduction how the samples were constructed for the cross-sectional and longitudinal components of the 1982-1984 NLTCS. A more systematic review of this can be made from Figure 1.
|FIGURE 1: unavailable at the time of HTML conversion--will be added at a later date.|
In Figure 1 we present a time line for the 1982-1984 (and a proposed 1988) NLTCS which identifies the dates of the surveys, the dates for which Medicare Part A data are to be collected and the survey instruments applied at each date. The 1988 survey is currently in a tentative planning phase. All other elements of the survey and service use data collection are in-place except for the proposed collection of death certificates for decedents over the period 1982 to 1989.
We can see that the sample was originally "frozen" as of April 1, 1982 and contained 35,789 persons. Survey work for round 1 began in June and continued to October 1982 and produced 6,088 responses from the 6,393 persons identified as chronically disabled. In addition to the survey of disabled persons a separate survey of 1,925 caregivers (1,626 continuing caregivers and 299 caregivers who discontinued care) who were identified as having provided care to a subsample of the 6,393 persons who screened into the survey. In addition to the 6,393 community dwelling elderly disabled, 1,992 persons were found to be in institutions, either before April 1 (N=1708) or who became institutionalized between April 1 and the screening date (N=284). Thus, though no interviews in 1982 were conducted of institutionalized persons, and we cannot identify Medicaid and private pay institutionalized persons from the Medicare files, we can identify the total set (N=1992) of institutionalized persons from the screen.
On April 1, 1984, the sample components of the 1984 survey were fixed and field work again conducted between June and October 1984. At this time three survey instruments were applied to nearly 10,000 persons. One instrument was essentially the same questionnaire as was applied to the 1982 community dwelling, disabled elderly population. A second instrument was the institutional questionnaire which allowed us to examine the retrospective reports of the institutional histories of all persons institutionalized on April 1. These reports covered all facets of institutionalization (Medicaid and private pay as well as Medicare). The third type of survey was the "next of kin" questionnaire on health services received during the terminal phase of the illness for deceased persons who were reported as disabled in 1982 and who died in the two-year intervening period. Medicare Part A data cover all service use from January 1, 1980, to currently October 1986.
To get a better understanding of the size of the sample components and their change in sample status between 1982 and 1984, examine Figure 2.
|FIGURE 2. Component Sub-Populations of 1982 and 1984 NLTC Surveys: unavailable at the time of HTML conversion--will be added at a later date.|
We see several different types of numbers in the figure. First, above each block is a single number which represents the number of persons in that state at that time. Thus, there were 25,541 persons (of 31,934 who were not institutionalized and who responded to at least the telephone screen) who were determined to be non-disabled, community dwellers in 1982. In 1984 there were 14,130 such persons--a number much smaller than the 25,541 because only 47.4% of the 1982 non-disabled group was screened.
Under each block is a set of four numbers. For 1982 these describe the number of persons in that state who ended up in one of the four receiving states in 1984. Thus, 9,220 persons who were non-disabled, aged 65+ and sampled (of the 47.4% of people who were non-disabled in 1982) turned out to be non-disabled in 1984. Of this group, 1,562 became disabled and were interviewed in 1984, 348 persons became institutionalized in 1984, and 970 died.
The corresponding numbers for 1984 tell us where persons in those states come from. Thus, of the 6,182 persons receiving the detailed survey in 1984, 1,562 were not detailed in 1982, 4,114 were people who were disabled in 1982 (but who were not necessarily disabled in 1984--thus long term improvements in health and functional status can be tracked over the two-year period), 53 persons were interviewed in 1984 in the community who were institutionalized in 1982, and 453 persons became disabled and were interviewed from the sample of 4,916 persons drawn from those aged 63 or 64 in 1982. The deceased block shows that a total of 3,219 persons died from the four sample components over the two years.
One issue that arises in evaluating the 1982-1984 NLTCS is that, in order to increase its precision, a two-stage sample capture procedure was used to identify community dwelling disabled persons. Thus, it does not provide detailed survey data on various groups. For example, though it divides the total sample in 1982 into the set of all community disabled persons, the set of all institutionalized persons, and the set of all non-disabled, non- institutionalized persons, it provides no detailed data on non-institutional, non-disabled persons. The characteristics of such persons are described in the recent 1984-1986 Supplement on Aging (SOA)-Longitudinal Supplement on Aging (LSOA) of the National Health Interview Survey. The SOA-LSOA provides far less information on the disabled extremely elderly (only 876 persons over age 85 were identified in 1984) and both smaller numbers (~1,500) and less detailed information on the functionally impaired and the formal and informal care services they receive. Thus, each of these surveys complement one another but provide very different samplings of target populations and very different (and specially tailored) instruments. Likewise, the 1985 NNHS is being followed-up in 1987. That survey gives us much larger numbers and more specialized information than the NLTCS. However, it does not contain a true admission cohort. Thus, the three surveys may be reviewed as complementary in terms of sample coverage and instrumentation. This is illustrated in the coordinated time lines of the three surveys presented in Figure 3.
|FIGURE 3. TIME LINES FOR THREE NATIONALLY REPRESENTATIVE LONGITUDINAL SURVEYS: unavailable at the time of HTML conversion--will be added at a later date.|
The three sets of longitudinal surveys provide a powerful, and cost effective base battery of surveys to monitor the health and functional status of the elderly population and its consumption of acute and LTC services.