MEPS-HC-229I: Appendix to MEPS 2021 Event Files HC-229A - HC-229H

August 2023

Agency for Healthcare Research and Quality
Center for Financing, Access, and Cost Trends
5600 Fishers Lane
Rockville, MD 20857
(301) 427-1406

Table of Contents

A. Data Use Agreement
B. Background
1.0 Household Component
2.0 Medical Provider Component
3.0 Survey Management and Data Collection
C. Technical and Programming Information
1.0 General Information
2.0 Data File Information
2.1 Codebook Format
2.2 Variable Naming and Source
2.3 Contents of Condition-Event Link File (CLNK)
2.4 ICD-10-CM, CCSR1X, CCSR2X, and CCSR3X
3.0 Merging/Linking MEPS Data Files
3.1 Limitations/Caveats of the CLNK File
3.2 National Health Interview Survey
3.3 Using MEPS Data for Trend Analysis
3.4 Longitudinal Analysis
References

A. Data Use Agreement

Individual identifiers have been removed from the micro-data contained in these files. Nevertheless, under sections 308 (d) and 903 (c) of the Public Health Service Act (42 U.S.C. 242m and 42 U.S.C. 299 a-1), data collected by the Agency for Healthcare Research and Quality (AHRQ) and/or the National Center for Health Statistics (NCHS) may not be used for any purpose other than for the purpose for which they were supplied; any effort to determine the identity of any reported cases is prohibited by law.

Therefore in accordance with the above referenced Federal Statute, it is understood that:

  1. No one is to use the data in this data set in any way except for statistical reporting and analysis; and

  2. If the identity of any person or establishment should be discovered inadvertently, then (a) no use will be made of this knowledge, (b) the Director Office of Management AHRQ will be advised of this incident, (c) the information that would identify any individual or establishment will be safeguarded or destroyed, as requested by AHRQ, and (d) no one else will be informed of the discovered identity; and

  3. No one will attempt to link this data set with individually identifiable records from any data sets other than the Medical Expenditure Panel Survey or the National Health Interview Survey. Furthermore, linkage of the Medical Expenditure Panel Survey and the National Health Interview Survey may not occur outside the AHRQ Data Center, NCHS Research Data Center (RDC) or the U.S. Census RDC network.

By using these data you signify your agreement to comply with the above stated statutorily based requirements with the knowledge that deliberately making a false statement in any matter within the jurisdiction of any department or agency of the Federal Government violates Title 18 part 1 Chapter 47 Section 1001 and is punishable by a fine of up to $10,000 or up to 5 years in prison.

The Agency for Healthcare Research and Quality requests that users cite AHRQ and the Medical Expenditure Panel Survey as the data source in any publications or research based upon these data.

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B. Background

1.0 Household Component

The Medical Expenditure Panel Survey (MEPS) provides nationally representative estimates of health care use, expenditures, sources of payment, and health insurance coverage for the U.S. civilian noninstitutionalized population. The MEPS Household Component (HC) also provides estimates of respondents’ health status, demographic and socio-economic characteristics, employment, access to care, and satisfaction with health care. Estimates can be produced for individuals, families, and selected population subgroups. The panel design of the survey includes five rounds of interviews covering two full calendar years. Additional rounds were added in 2020 and 2021, covering third and fourth years respectively, to compensate for the smaller number of completed interviews in later panels. These extra rounds provide data for examining person level changes in selected variables such as expenditures, health insurance coverage, and health status. Using computer assisted personal interviewing (CAPI) technology, information about each household member is collected, and the survey builds on this information from interview to interview. All data for a sampled household are reported by a single household respondent.

The MEPS HC was initiated in 1996. Each year a new panel of sample households is selected. Because the data collected are comparable to those from earlier medical expenditure surveys conducted in 1977 and 1987, it is possible to analyze long-term trends. Each annual MEPS HC sample size is about 15,000 households. Data can be analyzed at either the person or event level. Data must be weighted to produce national estimates.

The set of households selected for each panel of the MEPS HC is a subsample of households participating in the previous year’s National Health Interview Survey (NHIS) conducted by the National Center for Health Statistics. The NHIS sampling frame provides a nationally representative sample of the U.S. civilian noninstitutionalized population. In 2006, the NHIS implemented a new sample design, which included Asian persons in addition to households with Black and Hispanic persons in the oversampling of minority populations. NHIS introduced a new sample design in 2016 that discontinued oversampling of these minority groups.

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2.0 Medical Provider Component

Upon completion of the household CAPI interview and obtaining permission from the household survey respondents, a sample of medical providers are contacted by telephone to obtain information that household respondents cannot accurately provide. This part of the MEPS is called the Medical Provider Component (MPC) and information is collected on dates of visits, diagnosis and procedure codes, charges and payments. The Pharmacy Component (PC), a subcomponent of the MPC, does not collect charges or diagnosis and procedure codes but does collect drug detail information, including National Drug Code (NDC) and medicine name, as well as amounts of payment. The MPC is not designed to yield national estimates. It is primarily used as an imputation source to supplement/replace household reported expenditure information.

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3.0 Survey Management and Data Collection

MEPS HC and MPC data are collected under the authority of the Public Health Service Act. Data are collected under contract with Westat, Inc. (MEPS HC) and Research Triangle Institute (MEPS MPC). Data sets and summary statistics are edited and published in accordance with the confidentiality provisions of the Public Health Service Act and the Privacy Act. The National Center for Health Statistics (NCHS) provides consultation and technical assistance.

As soon as data collection and editing are completed, the MEPS survey data are released to the public in staged releases, micro data files, and tables via the MEPS website and datatools.ahrq.gov.

Additional information on MEPS is available from the MEPS project manager or the MEPS public use data manager at the Center for Financing, Access, and Cost Trends, Agency for Healthcare Research and Quality, 5600 Fishers Lane, Rockville, MD 20857 (301-427-1406).

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C. Technical and Programming Information

1.0 General Information

This documentation describes the MEPS Public Use Release HC-229I, which is the Appendix to MEPS releases HC-229A through HC-229H. This release contains the condition-event link file (CLNK), provided in ASCII (with related SAS, SPSS, R, and Stata programming statements and data user information) and SAS data set, SAS transport file, Stata data set, and Excel file versions.

This documentation offers a brief overview of the content and structure of the files and the accompanying codebook. It contains the following sections:

  • Data File Information

  • Merging/Linking MEPS Data Files

For more information on MEPS HC sample design see Chowdhury et al. (2019). For information on the MEPS MPC design, see RTI International (2019). A copy of the survey instruments used to collect the information on this file, are available on the MEPS website.

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2.0 Data File Information

This public use data set consists of a data file containing variables for linkage of the MEPS 2021 event-level data files. The H229IF1 or CLNK file, is used for linking the MEPS Conditions file with the MEPS event files. The CLNK file contains 6 variables and has a logical record length of 71 with an additional 2-byte carriage return/line feed at the end of each record.

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2.1 Codebook Format

The codebook describes an ASCII data set (although the data are also being provided in a SAS data set, SAS transport file, Stata data set, and Excel file), and provides the following programming identifiers for each variable:

Identifier Description
Name Variable name
Description Variable descriptor
Format Number of bytes
Type Type of data: numeric (indicated by NUM) or character (indicated by CHAR)
Start Beginning column position of variable in record
End Ending column position of variable in record

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2.2 Variable Naming and Source

In general, variable names reflect the content of the variable. All variables contained on the file were derived from the CAPI.

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2.3 Contents of Condition-Event Link File (CLNK)

The CLNK file contains the variables needed to link each record on the MEPS 2021 Conditions file, HC-231, with one or more records on the MEPS 2021 event files, HC-229D through HC-229H. Section 3.0 contains additional information on completing this linkage.

The ten-character variable DUPERSID uniquely identifies each person represented on the file. The variable DUPERSID is the combination of the variables DUID and PID. All ID variables begin with the 2 digit panel number. There may be more than one record on the CLNK file for a specific DUPERSID value.

CONDIDX is the 13-digit ID that uniquely identifies each condition for a person and corresponds to a unique record on the MEPS 2021 Conditions file, HC-231. The variable CONDIDX is the combination of the variables DUPERSID and CONDN (see HC-231 for a description of CONDN). The 2-digit panel number is added in the beginning of CONDIDX. There may be more than one record on the CLNK file for a specific CONDIDX value.

EVNTIDX is the 16-digit number that uniquely identifies each event for a person and corresponds to a unique record on one of the MEPS 2021 event files, HC-229B through HC-229H. (EVNTIDX is not included on the 2021 Prescribed Medicines event file, HC-229A; rather, on this file the variable for linking with EVNTIDX on the CLNK file is LINKIDX.) There may be more than one record on the CLNK file for a specific EVNTIDX value. The 2-digit panel number is added in the beginning of EVNTIDX, and a 2-digit event type number is added to the end. The event type number indicates the type of event record and has been rolled up into the following values:

01 = MVIS - office-based medical provider visit event on MEPS release HC-229G or

OPAT - outpatient department visit event on MEPS release HC-229F or

EROM - emergency room visit event on MEPS release HC-229E or

STAZ - inpatient hospital stay event on MEPS release HC-229D or

HVIS - home health visit event on MEPS release HC-229H

03 = PMED - prescribed medicine event on MEPS release HC-229A

CLNKIDX is the 29-digit number that uniquely identifies each record on the CLNK file and is the combination of CONDIDX + EVNTIDX. There is just one record on this file for each value of CLNKIDX, i.e., each unique combination of CONDIDX + EVNTIDX.

The variable EVENTYPE indicates the type of event record, and has the following values:

1 = MVIS - office-based medical provider visit event contained on MEPS release HC-229G

2 = OPAT - outpatient department visit event contained on MEPS release HC-229F

3 = EROM - emergency room visit event contained on MEPS release HC-229E

4 = STAZ - inpatient hospital stay event contained on MEPS release HC-229D

7 = HVIS - home health visit event contained on MEPS release HC-229H

8 = PMED - prescribed medicines event contained on MEPS release HC-229A

PANEL is a constructed variable used to specify the panel number for the interview in which the condition was reported. PANEL will indicate either Panel 23, Panel 24, Panel 25, or Panel 26. Panel 23 is the panel that started in 2018, Panel 24 is the panel that started in 2019, Panel 25 is the panel that started in 2020, and Panel 26 is the panel that started in 2021. The panel number is included as the first two digits of the DUID and DUPERSID.

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2.4 ICD-10-CM, CCSR1X, CCSR2X, and CCSR3X

ICD-10-CM diagnosis codes and Clinical Classification Software Refined (CCSR) codes are both used to group medical conditions into clinically meaningful categories. For the purposes of MEPS, one ICD-10-CM diagnosis code may map to up to three CCSR categories (CCSR1X, CCSR2X, CCSR3X) using the v2022.2 release of the CCSR for ICD-10-CM diagnoses. For more information on CCSR, visit the user guide for CCSR.

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3.0 Merging/Linking MEPS Data Files

This file is intended to be used in conjunction with other files. Specifically, the Conditions file (HC-231), the Prescribed Medicines event file (HC-229A), and event files HC-229B through HC-229H.

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3.1 Limitations/Caveats of the CLNK File

When using the CLNK file, analysts should keep in mind that (1) conditions are self-reported and (2) there may be multiple conditions associated with an event. Users should also note that not all events link to the Conditions file.

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3.2 National Health Interview Survey

Data from this file can be used alone or in conjunction with other files for different analytic purposes. Each MEPS panel can also be linked back to the previous years’ National Health Interview Survey public use data files. For information on obtaining MEPS/NHIS link files please see the MEPS website.

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3.3 Using MEPS Data for Trend Analysis

First, of course, we note that there are uncertainties associated with 2020 and 2021 data quality as discussed in the Survey Sample Information section of the Consolidated PUF document (HC-233). Preliminary evaluations of a set of MEPS estimates of particular importance suggest that they are of reasonable quality. Nevertheless, analysts are advised to exercise caution in interpreting these estimates, particularly in terms of trend analyses since access to health care was substantially affected by the COVID-19 pandemic as were related factors such as health insurance and employment status for many people.

MEPS began in 1996, and the utility of the survey for analyzing health care trends expands with each additional year of data; however, when examining trends over time using MEPS. The length of time being analyzed should be considered. In particular, large shifts in survey estimates over short periods of time (e.g. from one year to the next) that are statistically significant should be interpreted with caution, unless they are attributable to known factors such as changes in public policy, economic conditions, or MEPS survey methodology.

With respect to methodological considerations, in 2013 MEPS introduced an effort focused on field procedure changes such as interviewer training to obtain more complete information about health care utilization from MEPS respondents with full implementation in 2014. This effort likely resulted in improved data quality and a reduction in underreporting starting in the second half of 2013 and throughout 2014 full year files and has had some impact on analyses involving trends in utilization across years. The changes in the NHIS sample design in 2016 and 2018 could also potentially affect trend analyses. The new NHIS sample design is based on more up-to-date information related to the distribution of housing units across the U.S. As a result, it can be expected to better cover the full U.S. civilian, noninstitutionalized population, the target population for MEPS, as well as many of its subpopulations. Better coverage of the target population helps to reduce the potential for bias in both NHIS and MEPS estimates.

Another change with the potential to affect trend analyses involved major modifications to the MEPS instrument design and data collection process, particularly in the events sections of the instrument. These were introduced in the Spring of 2018 and thus affected data beginning with Round 1 of Panel 23, Round 3 of Panel 22, and Round 5 of Panel 21. Since the Full Year 2017 PUFs were established from data collected in Rounds 1-3 of Panel 22 and Rounds 3-5 of Panel 21, they reflected two different instrument designs. In order to mitigate the effect of such differences within the same full year file, the Panel 22 Round 3 data and the Panel 21 Round 5 data were transformed to make them as consistent as possible with data collected under the previous design. The changes in the instrument were designed to make the data collection effort more efficient and easy to administer. In addition, expectations were that data on some items, such as those related to health care events, would be more complete with the potential for identifying more events. Increases in service use reported since the implementation of these changes are consistent with these expectations. Data users should be aware of possible impacts on the data and especially trend analyses for these data years due to the design transition.

Process changes, such as data editing and imputation, may also affect trend analyses. For example, users should refer to the Section 2.5.11 in the 2021 Full Year Consolidated file (HC-233) and, for more detail, the documentation for the prescription drug file (HC-229A) when analyzing prescription drug spending over time.

As always, it is recommended that data users review relevant sections of the documentation for descriptions of these types of changes that might affect the interpretation of changes over time before undertaking trend analyses.

Analysts may also wish to consider using statistical techniques to smooth or stabilize analyses of trends using MEPS data such as comparing pooled time periods (e.g. 1996-1997 versus 2011-2012), working with moving averages, or using modeling techniques with several consecutive years of MEPS data to test the fit of specified patterns over time.

Finally, statistical significance tests should be conducted to assess the likelihood that observed trends are not attributable to sampling variation. In addition, researchers should be aware of the impact of multiple comparisons on Type I error. Without making appropriate allowance for multiple comparisons, undertaking numerous statistical significance tests of trends increases the likelihood of concluding that a change has taken place when one has not.

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3.4 Longitudinal Analysis

Panel-specific longitudinal files are available for downloading in the data section of the MEPS website. For all four panels (Panel 23, Panel 24, Panel 25, and Panel 26), the longitudinal file comprises MEPS survey data obtained in all rounds of the panel and can be used to analyze changes over the entire length of the panel. For Panel 24, a file representing a three-year period will also be established and updated to cover four years with the release of 2022 data. For Panel 23, a file representing a four-year period will be established. Variables in the file pertaining to survey administration, demographics, employment, health status, disability days, quality of care, patient satisfaction, health insurance, and medical care use and expenditures were obtained from the MEPS full-year Consolidated files from the years covered by each panel.

For more details or to download the data files, please see Longitudinal Weight files at the AHRQ website.

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References

Chowdhury, S.R., Machlin, S.R., Gwet, K.L. Sample Designs of the Medical Expenditure Panel Survey Household Component, 1996-2006 and 2007-2016. Methodology Report #33. January 2019. Agency for Healthcare Research and Quality, Rockville, MD.

RTI International (2019). Medical Provider Component (MEPS-MPC) Methodology Report 2017 Data Collection. Rockville, MD. Agency for Healthcare Research and Quality.

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5600 Fishers Lane
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