Methodology Report #1: Design and Methods of the Medical Expenditure Panel Survey Household Component

by Joel Cohen, Ph.D., Agency for Health Care Policy and Research

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Introduction

The Medical Expenditure Panel Survey (MEPS) is the third in a series of nationally representative surveys of medical care use and expenditures sponsored by the Agency for Health Care Policy and Research (formerly the National Center for Health Services Research). The first of these surveys, called the National Medical Care Expenditure Survey (NMCES), was conducted in 1977, and the second, called the National Medical Expenditure Survey (NMES), in 1987. The 1996 MEPS, which is cosponsored by the National Center for Health Statistics (NCHS), will update the 1987 data to reflect the dramatic changes that have occurred in the U.S. health care system over the last decade.

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Background

Major changes have taken place in the Nation's health care delivery system since NMES was conducted almost 10 years ago. The most notable is the rapid expansion of managed care arrangements such as HMOs (health maintenance organizations), PPOs (preferred provider organizations), and other provider networks that seek to minimize increases in health care costs. New hybrid forms of health insurance coverage also have appeared. Changes such as these have affected both the private and public sectors. The new MEPS provides information about the current state of the health care system in the United States and the changes that have taken place since the last national survey of medical expenditures was conducted in 1987. The information collected by MEPS also provides valuable baseline data for use in evaluating future changes in the system.

The MEPS study design was developed to enhance the capabilities to study changes in health care delivery and the effects of new health policies. These are important objectives in view of the various health reform initiatives being implemented by States and the Federal Government. The MEPS design allows for the production of annual estimates for 2 calendar years. It also permits the tracking of changes in employment, income, health status, and medical care use and expenditures over the 2 consecutive years during which households will be interviewed. In addition, National Health Interview Survey (NHIS) baseline data are available for persons in the MEPS panels, thereby adding another data point for comparisons of change over time.

MEPS extends the NMES series of studies on medical expenditures and health insurance and provides, for the first time, data suitable for detailed analysis of trends and changes in these areas. The survey is a unique resource for a number of reasons, including:

• Scope. MEPS provides information on a broad spectrum of the population. The survey sample base represents the civilian noninstitutionalized population and, in a separate component, the population institutionalized in nursing homes. MEPS also provides information on many types of health care services, expenditures, and sources of payment for both individuals and families.

• Population basis. Because MEPS is a survey of persons, population groups that are or may become of special policy concern can be identified and analyzed. This is especially important for analyzing the effect of particular eligibility requirements on the enrollment and budgets of public programs and on those who are not eligible for such programs.

• Cost-effectiveness. MEPS will collect data needed by groups that might otherwise either sponsor separate or overlapping surveys, or do without crucial information needed for important decisions. Experience has demonstrated that broad-based data on use, expenses, and financing of health care collected from a nationally representative sample can meet the data needs of a wide variety of users in a cost-effective manner.

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Household Component

The sample design of the NMES household surveys has been revised for MEPS. The MEPS sample is not defined through an initial screening round. Instead, it is selected as a nationally representative subsample of households that participated in NHIS. The 1996 MEPS sample (based on the 1995 NHIS) is being carried forward into 1997 and combined with a new subsample of households responding to the 1996 NHIS. These two panel samples (the 1996 MEPS sample and the new MEPS selections from the 1996 NHIS) will jointly define the sample base for the 1997 MEPS Household Component. Table 1 shows the study design of the 1996 and 1997 MEPS Household Components. Table 2 summarizes various features of the study design of the Household Component.

In 1996, the MEPS sample linked to the 1995 NHIS was selected. It was drawn from a nationally representative NHIS subsample that included 195 primary sampling units and approximately 1,700 segments, yielding approximately 10,500 responding NHIS households. These households were recontacted in MEPS. This NHIS subsample reflects an oversample of Hispanics and blacks. Other groups with high public policy relevance in the areas of health care use and financing are oversampled as part of the MEPS 1997 panel to improve the precision of the estimates for those groups.

Households selected for participation in the 1996 or 1997 MEPS Household Components are interviewed in person five times (Rounds 1-5) and a last time during a brief telephone interview (Round 6). The rounds of data collection are spaced approximately 4 months apart. The interviews take place with a family respondent who reports for himself or herself and for other family members.

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Preliminary Contact

Mail and telephone contacts take place prior to the first MEPS interview with the NHIS participating households selected for each MEPS panel (Round 1). The purpose of the preliminary contact is to enlist the household respondent into MEPS and plan for the delivery of record-keeping materials before the study observation period begins on January 1st of the survey year. In December, an advance letter announcing MEPS is mailed to the family respondent at the address where the NHIS interview was conducted. An interviewer follows up on the letter with a telephone call to confirm its arrival, verify the identity of the household, identify the MEPS family respondent (if different from the NHIS respondent), and announce the future mailing of a study calendar and record file. These materials are sent, along with $5 to compensate respondents for the time and effort devoted to keeping records in preparation for the Round 1 interview. An interviewer telephones a second time to confirm the arrival of these materials and arrange for a convenient time to conduct the Round 1 interview.

Households that do not have a telephone or cannot be reached using the telephone number from NHIS are contacted by mail and asked to return a postcard identifying a telephone number where they can be contacted (e.g., the number at work or a neighbor's house).

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Core Rounds

Data collection for the MEPS Household Component takes place using a computer-assisted personal interview (CAPI) system. A core instrument is administered in each of the first five rounds of data collection, with periodic supplements added in selected rounds to deal with specific topics in greater depth. Dependent interviewing methods, in which respondents are asked to confirm or revise data provided in earlier interviews, is used to update information in several of the core questionnaires, such as employment and health insurance, after the initial interview.

Core Instrument

The core instrument is used to collect data about all persons in sampled households. It includes questionnaires on demographics, health status and conditions, use, charges and payments, prescribed and over-the-counter medicines purchased, employment, and health insurance.

Periodic Supplements

Supplements scheduled for inclusion in the survey include questionnaires on access to and satisfaction with care, income and assets, long-term care, and alternative care (which includes approaches to health care that are different from those typically practiced by medical doctors in the United States, such as acupuncture and homeopathic treatments).

Self-Administered Questionnaire

All adults in sample households are asked to complete a self-administered questionnaire in Round 2. This questionnaire collects information about health behaviors and opinions that would be difficult, if not impossible, to collect on a proxy basis from the family respondent. Similar information is collected for children as part of the regular interview with the household survey respondent, usually the mother.

Medical Provider Permission Forms

Signed permission forms are requested in Round 1, much earlier than in past NMES studies, in order to expedite the timetable for the later Medical Provider Component of the survey, which collects data about specific medical events directly from providers. Results from a previous methodological study suggested that early requests for signed permission forms involving office-based physicians have a modest negative effect on survey cooperation rates in later rounds. Therefore, the requests for signed permission forms in Round 1 are limited to events taking place in hospitals. In Round 2 and subsequent rounds, requests for signed permission forms apply to all types of providers included in the Medical Provider Component of MEPS (that is, hospitals, physicians, and home health agencies), including those associated with use reported in Round 1.

Health Insurance Permission Forms

Signed permission forms are needed to contact sources of employment and private health insurance coverage in the Insurance Component of the survey, which collects data directly from individuals' sources of health insurance (typically their employers). These requests are initiated in Round 2 and apply to the insurance sources associated with plans held at the time of the Round 1 interview.

Health Insurance Policy Booklet Requests

Following procedures tested successfully in a previous methodological study, MEPS interviewers ask respondents to provide health insurance booklets or other summary materials that describe the characteristics of private plans held by family members at the time of the Round 1 interview. The requests for policy information include all sources of private insurance coverage, not just employment-related coverage. Respondents are reimbursed $15 for the time and effort involved in procuring policy booklets.

Provider Directories

To assist in the identification of medical providers and the preparation of an unduplicated list of medical providers, interviewers use a computerized database (directory) of health providers that has been loaded into the CAPI laptop computer. With search software loaded into the laptops, interviewers can query the database of providers in the course of the MEPS interview. If a match is found in the database for the provider specified by the household respondent, the matched directory record is associated with the household member. Directory records include the following information for each provider: a unique provider identification number; the provider's name, address, and telephone number; and the provider's specialty (for individual office-based physicians).

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Uses of Data

At the most basic level, the objective of the MEPS Household Component is to collect data that can be used to produce annual estimates for a variety of measures related to the characteristics of individuals; their health insurance coverage; and their health care use, expenditures, and sources of payment. The data can also be used to support behavioral analyses that inform researchers and policymakers about how the characteristics of individuals and families, including their health insurance, affect medical care use and spending.

Data obtained in this study will be used to produce the following national estimates for calendar years 1996 and 1997:

• Annual estimates of health care use and expenditures for persons and families.

• Annual estimates of sources of payment for health care expenses, including amounts paid by public programs, such as Medicare and Medicaid, and by private insurance, as well as out-of-pocket payments.

• Annual estimates of health care use, expenditures, and sources of payment for persons and families by type of service, including inpatient hospital stays, ambulatory care, home health care, dental care, and purchases of prescribed and over-the-counter medicines.

• The number and characteristics of the population eligible for each of the public programs, including the use of services and expenditures of the population eligible for benefits under Medicare, Medicaid, CHAMPUS and CHAMPVA (Civilian Health and Medical Program for the Uniformed Services and Civilian Health and Medical Program, Veterans' Affairs), and the Department of Veterans' Affairs.

• The number, characteristics, use of services, expenditures, and benefits of persons and families with individual or group coverage; commercial or nonprofit coverage; and coverage through HMOs or other managed care arrangements.

In addition to national estimates, data collected in this longitudinal study will be used to study determinants of the use of services and expenditures, and the effects of individual characteristics and policy changes on medical care use and expenses. These behavioral analyses will include studies of:

• Social and demographic factors such as employment and income.

• Methods of financing health care and health insurance.

• Health habits, lifestyles, and behavioral patterns of individuals and families.

• Health needs of specific subpopulation groups of current or potential policy interest, such as the elderly and members of racial or ethnic minorities.

Finally, data collected in this survey­in conjunction with data from the 1977 NMCES and the 1987 NMES­will be used to study trends in the nature and distribution of national health expenditures, sources of care, and amounts and types of services used by the U.S. noninstitutionalized population.

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• Note: MEPS is Medical Expenditure Panel Survey. NHIS is National Health Interview Survey.

• Note: CAPI is computer-assisted personal interview. MEPS is Medical Expenditure Panel Survey.

Source: Agency for Health Care Policy and Research, Center for Financing, Access, and Cost Trends

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