HHS Plan for Integration of Surveys. Population-Based Surveys


The National Health Interview Survey (NHIS) and the National Medical Expenditure Survey (NMES) serve as the foundations for the consolidated household-based health and health economic surveys. The NHIS would continue as an annual survey and serve as the nucleus of an integrated approach to the Department's personal household interview surveys. The NHIS sample of approximately 40,000 households (105,000 individuals) would be administered a core household interview based on the questionnaire redesigned for 1996 implementation. The core includes questions on demographics, SES, health status, utilization, insurance coverage and access. In addition to obtaining information on all household members, additional core questionnaires are administered to a sample adult and a sample child. Periodic modules in the area of utilization, behaviors, and health status collect more detailed information on a rotating basis.

The NHIS national core sample would serve as a sampling frame for the Medical Expenditure Panel (MEP), which would replace the periodic NMES. This panel survey would obtain national annual estimates on health care utilization, expenditures, insurance coverage and sources of payment for the noninstitutionalized population, and for policy relevant subgroups that include the poor and near poor, the elderly, individuals with functional limitations and individuals predicted to incur high levels of medical expenditures. The MEP would be implemented in 1996, based on the sample from the 1995 NHIS.

The MCBS will be closely coordinated with the MEP in terms of 1) greater questionnaire coordination; 2) analytic linkages of the MCBS and MEP samples to increase the power of each survey; and 3) possible offsetting reductions in sample size if analytic goals can be achieved through such linkages. Further steps to consolidate the MEP and MCBS will be evaluated as the MEP reaches a steady annual state in 1998.

This sample design integration would yield a significant reduction in data collection costs associated with the separate screening interview currently planned in NMES III to facilitate oversampling of policy relevant population subgroups.

The consolidated NHIS and MEP would serve as an integrated, flexible sampling frame for more specialized studies addressing a broad range of health issues, furthering HHS's goals for integration and consolidation of survey efforts. The NHIS would serve as the sampling frame for the MEP, and could serve as the basis for other surveys that would require large population size, geographic distribution, and a common core of information from which to select sample persons. Households that are included in the MEP could serve as the sampling frame where a study required a baseline of detailed expenditure data, a longitudinal design, or other features of the MEP design.

These specialized studies would take a number of forms, ranging from special topic supplements to the NHIS or MEP (such as the current NHIS immunization and Healthy People 2000 supplements); targeted followup studies that involve a re-interview with the household (such as the current disability survey); or more involved followup or panel studies.

Two that will be included in the consolidated survey plan include:

A Health Examination Component - designed to obtain objectively measured data on health conditions for prevention, nutrition monitoring, monitoring environmental exposures and immunization protection levels. In 1998, a modification to the current NHANES will be implemented for two years, involving a household examination on a sample of persons identified in the NHIS. A limited physical examination (height, weight, blood pressure, etc.) will be administered, and blood specimens will be collected for extensive laboratory tests. In the year 2000, a more extensive NHANES, involving a complete examination, dietary interview, biochemistries, and more extensive and specialized tests, will be implemented. This NHANES would be instituted on a continuous basis, with 3 years of data collection required to reach a sample for national estimates. Samples each year would be drawn from the NHIS.

A Component Addressing Family Related Issues - designed to obtain estimates of reproductive health, family formation, dissolution and other dynamics addressed by the current NSFG, already linked to the NHIS sample. This component would be part of the consolidated survey plan at the time the next NSFG would have been fielded, in the year 2000.

In addition, possible components include:

A Consumer Survey - designed to obtain more in-depth consumer data on satisfaction, preference and access to the health care system. Such a panel, for example, might include persons that changed health plans, experienced high utilization, or incurred significant out-of-pocket costs, as identified through the MEP questionnaire.

A Substance Abuse Survey - designed to address substance abuse and mental health issues similar to surveys such as the National Household Survey of Drug Abuse (see Tab F for discussion).

Design of the Medical Expenditure Panel (MEP)

The MEP is specified as a continuous survey with sample peaks at five year intervals. A 1996 MEP sample of 10,000 households, reduced from the intial plan for the 1996 NMES, will be drawn from the 1995 NHIS, with additional sample added from NHIS in 1997 to meet original precision requirements for groups such as the functionally disabled, children with functional limitations, individuals below 200 percent of the poverty level, and individuals likely to incur high medical expenditures.

The 1987 NMES II and the designed 1996 NMES III can be considered the conventional versions of data collection related to health care utilization, expenditures, employment, and health insurance coverage. There is no need for such an expansive data collection, with respect to both sample size and breadth of information, at intervals less than 9 or 10 years. What is needed is the ability to continuously monitor health care utilization, expenditures, and health insurance coverage and to examine changes over time.

To meet these goals and to permit limited resources to be allocated to other data collection efforts within a ten year cycle, a continuous MEP survey is specified, which has sample size peaks at five year intervals starting in 1997, that satisfy national precision requirements for policy relevant population subgroups (12,600 MEP households in addition to the MCBS). In the off-years of the survey (e.g. 1998-2001, 2003-2006), the sample would be reduced in scale (8,000 MEP households in addition to the MCBS), but with sufficient sample for national estimation and for major policy relevant population subgroups of interest (e.g, the poor/near poor). The survey would also include a longitudinal component, with a nationally representative subsample of the MEP households followed for a period of two years.

The following summarizes the phase-in and ongoing cycles of the MEP, by calendar year:

1995: The sample persons (approximately 10,000) from a sub-set of PSU's from the second and third quarter of the 1995 NHIS will be selected to participate in the 1996 MEP. This will require a change in the current plan for Phase II of the Disability Survey tied to the 1995 NHIS, and also require that the NHIS sample be released by November 1995. The NHIS includes an oversampling of blacks and Hispanics, but not other groups that would have been screened for the original 1996 NMES.

1996: Conduct MEP on a sample of 10,000 households (reduced from the original NMES III design of 14,500 households). Most of this sample (8,000 households) would be followed for two years; the remaining 2,000 households would be followed for three years, providing longitudinal data to facilitate analysis of change over time. Households sampled in 1996 and 1997 would be interviewed using an efficient conventional design--that is, the full breadth of data of interest (utilization, expenditures, health insurance, health status, access to care, long term care supplement), but to the extent possible, using more efficient data collection approaches such as telephone contacts. All households in 1996 and 1997 would be included in follow-back studies of medical providers and health insurance providers (MPS and HIPS).

1997: A new panel of 3,000 households selected from the 1996 NHIS would begin, in addition to the continuation of the 1996 panel of 10,000. This 1997 panel would be followed for two years. Coupled with data from the MCBS, this would provide the department with the analytic capabilities first proposed for the 1996 NMES III with respect to sample size. The same instruments used during 1996 would be administered during 1997.

1998: A new panel of 3,000 households selected from the 1997 NHIS would begin; coupled with the 2,000 households from 1996 and the 3,000 household panel from 1997, the overall sample size would be 8,000 cases. This 8,000 case sample of households is seen as the minimum size to permit monitoring of utilization, expenditures, and insurance among the population subgroups of policy interest (e.g., poor/near-poor).

The questionnaire used in 1998 would be a reduced questionnaire, with a central focus on utilization, expenditure, and insurance information. Limited MPS and HIPS information, with a 25 percent reduction in the HIPS sample.

The panel selected in 1998, and each subsequent year, would be followed for two years.

1999: A new panel of 5,000 households and a continuation of the 1998 panel of 3,000 households interviewed with the reduced questionnaire. Limited MPS and HIPS information, with a 25 percent reduction in the HIPS sample.

2000: A new panel of 3,000 households and a continuation of the 1999 5,000 household panel interviewed with the reduced questionnaire. Limited MPS and HIPS information, with a 25 percent reduction in the HIPS sample.

2001: A new panel of 5,000 households and a continuation of the Year 2000 panel of 3,000 households interviewed with the reduced questionnaire. Limited MPS and HIPS information, with a 25 percent reduction in the HIPS sample.

2002: To permit mid-cycle estimation (from a sample size perspective) paralleling the capabilities of the 10-year conventional version, in 2002, we would recommend a new panel of 8,000 households (added to the 5,000 panel from 2001). Half of this new panel would be interviewed only for one calendar year; the remaining would be followed into 2003. Content of the household questionnaire could be limited to the content from the previous three years or slightly expanded (e.g., administer the access to care supplement). Similarly, the questionnaire content of the MPS or HIPS follow-back could be assessed and if necessary, conducted for a subset of cases.

Drop back to an overall sample of 8,000 households, with 4,000 continuing from the previous year for each of the years. Content similar to 1999-2001.

2006: Begin 10-year cycle again, with increase to 10,000 cases overall (new panel of 6,000 selected in 2006). Expanded household questionnaire and full sample of MPS and HIPS.

Expanded and Enhanced Analytic Capabilities

By moving to this consolidated, annual household data collection effort, the Department expands and enhances its analytic capabilities as described below:

• Retains the design of the core NHIS household interview. This core will provide cross-sectional population statistics on health status and health care utilization with sufficient sample size to allow for analyses based on breakdown of detailed age, race, sex, income and other socio-demographic characteristics, and also will allow for data on a broad range of topics currently provided by the NHIS.

• Retains the analytical capacity to obtain both annual and quarterly population estimates of health care utilization and the prevalence of health conditions for the nation and for policy relevant population subgroups.

• Provides the ability to model individual (and family-level) health status, access to care and use, expenditure, and insurance behavior over the year and examine the distribution of these measures across individuals. The longitudinal feature of the survey to collect data over multiple years further enhances the capacity to model behavior over time.

• Provides the ability to relate data from a detailed survey sample (e.g., MEP) to a larger population sample (e.g., NHIS) to enhance the utility of the MEP for national health account estimation and microsimulation modeling, including disaggregation by age group or geographic area.

• Provides the potential to expand to State-level estimates for marginal costs using the enhanced 358 PSU sample design of the NHIS.

• The longitudinal (over several years) aspect of the consolidated data collection effort provides the following:

- An increase in statistical power to examine change or make comparisons over time.

- The capacity to examine changes over time as well as changes in the relationship among measures of health status, access to care, health care use, expenditures, health insurance coverage, employment, functional limitations and disabilities, and demographic characteristics.