IPUMS MEPS Variable Builder User Guide

Topics covered in this user guide include:

Why did we create the IPUMS MEPS Variable Builder?

MEPS-HC data include rich information on events and medical conditions that researchers often want to use to summarize, for example, the number of hospitalizations an individual experienced during specific calendar months or interview rounds, or the total annual expenditures related to asthma. But performing these calculations requires substantial data manipulation skills, which limits use of these rich data. Event records list information about characteristics of each medical visit, inpatient stay, or other medical expense for an individual, including what was spent on each medical event. Condition records contain information such as the type of condition and whether it was due to an accident or injury. Events can be associated with zero, one, or multiple conditions; similarly, condition records can be associated with zero events (before 2018), one, or multiple events. Events and conditions can be linked to one another using a separate linking crosswalk that identifies each unique event-condition pair.

The IPUMS MEPS Variable Builder lowers barriers to accessing these rich, complex data.

What is the IPUMS MEPS Variable Builder?

The IPUMS MEPS Variable Builder enables users to build event summary variables from information in the MEPS-HC event (e.g., calendar month or interview round, payment source, event type) and medical condition records (e.g., the type of medical condition(s), whether associated condition(s) were due to an accident or injury). Using a point-and-click interface, researchers can create event summary variables that count events or sum expenditures across event records, filter counts and expenditure totals by user-specified criteria, and include the resulting person-level variables in their IPUMS extract. At this time, the variable builder does not include prescribed medicines data.

Using event variables and condition variables from linked event-condition records, we have created filters that users can apply to their variables, including time period (measured as calendar month or event round), payment source type (e.g., private health insurance, Medicaid, Medicare), and characteristics of medical conditions associated with the event, such as ICD 9 code (for 1996-2015), ICD 10 code (for 2016-forward), whether the condition was due to an accident or injury, and whether the accident or injury occurred at work. Users are able to create variables using one of two operations: Event Count or Add Up Expenditures.

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Supported Operations

The IPUMS MEPS Variable Builder allows for users to perform one of two operations to create their summary variables. First, by selecting the "Event Count" radio button at the top of the IPUMS MEPS Variable Builder page, users can create a variable that is the count of the number of event records that meet the criteria they imposed using the filter selections in the variable builder. Second, by selecting the "Add Up Expenditures" radio button at the top of the IPUMS MEPS Variable Builder page, users can create a variable that is the sum of the total annual expenditures for all events that meet the criteria they imposed using the filter selections in the variable builder.

NOTE: unless otherwise specified under the payment sources tab, counts include zero-dollar events. To exclude zero-dollar events from a count, select the "Specify payment source types" radio button on the "Payment Sources" tab and click the "Select / Deselect all" checkbox, making sure that the check boxes for all listed payment sources are also checked.

An Overview of Selection Criteria

How are selection criteria applied?

The IPUMS MEPS Variable Builder interprets selections within the same category (or tab) as "OR" rather than "AND" selections. That is, if a user makes two different selections within the same tab, such as both private insurance and Medicare under the Payment Source tab, the variable they create will sum expenditures for or count events paid for by private insurance OR by Medicare, rather than just expenditures for events that were jointly paid for by both private insurance AND Medicare.

The IPUMS MEPS Variable Builder interprets selections across different categories (or tabs) as "AND" rather than "OR" selections. That is, if a user makes selections under two different tabs, such as Time Period and ICD 10 code under the Condition ICD tab, only events that have both characteristics will be included in the sum or count. If a user makes a selection under the Condition ICD tab and the Condition Accident or Injury tab, the two selections will also be treated as "AND" selections.

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EVENT TYPE

The event selection menu allows users to select event types as defined the EVENTYPE variable. For all events, EVENTYPE indicates the AHRQ event file from which the record was derived. We include a description of each of the types of events included in the MEPS-HC data below. NOTE: While AHRQ includes prescribed medicines in the event files, IPUMS classifies these as a separate record type and does not currently offer them through the IPUMS MEPS Variable Builder.

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TIME PERIOD

The Time Period filter utilizes two variables: EVENTMM and EVENTRN.

EVENTMM represents the calendar month in which the event (EVENTYPE) occurred. For office-based medical provider visits, outpatient visits, emergency room visits, inpatient hospitalization stays, dental visits, and home health events, EVENTMM reports the month of the medical event. For inpatient hospitalization stays, EVENTMM reports the month the stay began.

NOTE: events with the Other Medical Expenses event type do not have an associated calendar month value (represented as an "NIU" value selection under the "Calendar Month" section in the variable builder). Any specific month selections other than NIU will result in the exclusion of Other Medical Expense event type records, even if Other Medical Expenses are selected under the "Event Type" menu.

EVENTRN represents for all events the MEPS interview round in which the event (EVENTYPE) was reported. In nearly all years, there are a total of five rounds.

NOTE: years 2020-2021 are an exception. In these years, the MEPS interview panel was extended to enhance data collection around the COVID-19 pandemic. In 2020 there are seven rounds, and in 2021 there are nine rounds. When released, the 2022 will also contain additional rounds, but the 2023 data are expected to return to the typical five round structure.

PAYMENT SOURCES

The Payment Source filter utilizes information across twelve different event-level payment source variables (see EVEXPSRC for links to more information about each payment source). For office-based visits, dental visits, other medical expenses, and home health visits, the payment source variables report the total expenditure by payer variables as they are found in the original MEPS-HC data. For outpatient provider visits, emergency room visits, and inpatient hospitalizations, they represent the sum of facility (EVEXPSRCFAC) and separately-billing medical provider expenditures (EVEXPSRCDR) by payer. Utilization and expenditure information in MEPS is collected on the household questionnaire for all event types; additional expenditure information is collected through a follow-back survey of the medical providers for a subsample of MEPS responding households (the Medical Provider Component), which is used to improve the quality of expenditure information provided by households. However, only household data were collected for non-physician visits, dental and vision services, other medical equipment and services, and home health care not provided by an agency. Please see our user note on MEPS healthcare expenditures for more information.

NOTE: Payments from other public sources (EVEXPOPU) and other private sources (EVEXPOPR) were discontinued after 2018. If these variable filters are selected for the construction of a variable using Add Up Expenditures operation, they will be treated as $0 expenditures in 2019 and later years. If they are selected for the construction of a variable using the Count operation, a value of 0 will be returned. To illustrate: beginning in 2019, if payments from other public or private sources are requested individually, the values of the resulting user-defined variable will be $0. If expenditures are added up across multiple payment source types, including other public or private sources, the resulting sum will equal the sum of expenditures $0 for other public sources and other private sources plus the expenditures paid for by other payment sources such as Medicaid, Medicare, or private insurance.

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CHARACTERISTICS OF ASSOCIATED CONDITIONS

The Conditions filter allows for filtering on characteristics of conditions associated with events: (1) the type of medical condition, as classified by either the World Health Organization's International Classification of Diseases (ICD) version 9 (for MEPS years 1996-2015) or version 10 (for MEPS years 2016 and later) and (2) whether the medical condition was caused by an accident or injury and, if so, whether the accident or injury occurred at work.

How does the MEPS variable builder handle events with no associated condition or more than one associated condition?

Medical events in the MEPS can be associated with zero, one, or multiple conditions. While most are associated with a single medical condition, it is important to understand how zero- or multiple-condition events are handled by the IPUMS MEPS Variable Builder. Events with no associated medical condition will be excluded from any summary event variables that include one or more codes from either of the two ICD coding schemas (ICD-9 or ICD-10) and/or accident/injury as a filtering criterion. Events associated with two or more conditions will be included only once in any sums or counts generated with the variable builder.

Consider, for example, the following case of a person who participated in the 2017 MEPS (mepsid value 2299531103) with three medical conditions (each with a unique value of MEPSCONDID) and two different emergency room visits (each with a unique value of MEPSEVNTID, Table 1). This person had one emergency room visit in January for viral or other specified intestinal infections (ICD-10 code A08) and volume depletion (ICD-10 code E86), for which their insurer, Medicaid (not shown in the table), paid $73.12. We know this is the same emergency room visit for both conditions because it has the same MEPSEVNTID value. They had another emergency room visit in October for influenza due to unidentified influenza virus (ICD-10 code J11), for which Medicaid paid $147.42.

Table 1. Event-Condition Pairs for MEPSID=2299531103 in the 2017 MEPS sample
MEPSID MEPSCONDID MEPSEVNTID ICD10CODE EVENTYPE EVENTMM EVEXPTOT
2299531103 22995311030021 2299531103001101 E86 Emergency room visit January 73.12
2299531103 22995311030011 2299531103001101 A08 Emergency room visit January 73.12
2299531103 22995311030031 2299531103003101 J11 Emergency room visit October 147.42

The output of the IPUMS MEPS Variable Builder is fairly straightforward in cases where only a single condition is selected or only one condition is associated with an event. If a user employed the MEPS Variable Builder interface to create an expenditure variable that added up all Emergency Room visits associated with influenza, they would get a value of $147.42 for this person. If they wanted, instead, to get a variable that reported the sum of expenditures for Emergency Room visits associated with intestinal infections, they would get a value of $73.12 for this person. In cases where an event is associated with more than one condition, the expenditure or event is only counted once when producing a sum of expenditures or count of events, even if all condition types associated with the event are selected from the condition menu. If users selected events associated with any ICD-10 condition, the "All" selection on the ICD-10 tab, they would get a total value of $73.12 + $147.42 = $220.54. If users specified only the condition of "volume depeltion" (or volume depletion and intestinal infections) they would also get a value of $73.12 for this person; while IPUMS MEPS Variable Builder will not double count expenditures, users who create multiple variables and then sum those directly in their statistical package could inadvertently double count expenditures.

NOTE: beginning in 2018, conditions were not reported in the MEPS data unless they were associated with at least one medical event during the year (in other words, only conditions that were "medically attended.") Prior to 2018, some conditions were not associated with medical events. Refer to our user note on condition, event, and prescribed medicine records for more information.

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Tips and Tricks for Using the Variable Builder

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Expected Zero Values

Below is a list of known cases where users should expect zero values from the IPUMS MEPS Variable Builder based on universe restrictions and changes in availability across samples.

  1. Other Medical Expenses with any calendar month selection (other than NIU) OR Other Medical Expenses with any condition selection will always produce zero values
  2. ICD-9 code selections will always produce zero values for sample years 2016 and onward
  3. ICD-10 code selections will always produce zero values for sample years 1996-2015
  4. Dental visits with any condition selection (ICD-9/10 code or Accident/Injury selection) will always produce zero values for sample years 2001-onward
  5. Selections for rounds 6 and higher will always produce zero values outside of the 2020-2021 sample years
  6. Other private and Other public payment source selections will produce zero values for sample years 2019-onward

Resources

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