MEPS HC-094E: 2005 Emergency Room Visits
September 2007
Agency for Healthcare Research and Quality
Center for Financing, Access, and Cost Trends
540 Gaither Road
Rockville, MD 20850
(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 Structure
2.2 Reserved Codes
2.3 Codebook Format
2.4 Variable Source and Naming Conventions
2.4.1 General
2.4.2 Expenditure and Source of Payment Variables
2.5 File Contents
2.5.1 Survey Administration Variables
2.5.1.1 Person Identifiers (DUID, PID, DUPERSID)
2.5.1.2 Record Identifiers (EVNTIDX, ERHEVIDX, FFEEIDX)
2.5.1.3 Round Indicator (EVENTRN)
2.5.1.4 Panel Indicator (PANEL)
2.5.2 MPC Data Indicator (MPCDATA)
2.5.3 Emergency Room Visit Event Variables
2.5.3.1 Visit Details (ERDATEYR-VSTRELCN)
2.5.3.2 Services, Procedures, and Prescription Medicines (LABTEST-MEDPRESC)
2.5.4 VA Facility (VAPLACE)
2.5.5 Condition and Procedure Codes (ERICD1X-ERICD3X,
ERPRO1X, ERPRO2X), and Clinical Classification Codes (ERCCC1X-ERCCC3X)
2.5.6 Flat Fee Variables (FFEEIDX, FFERTYPE, FFBEF05,
FFTOT06)
2.5.6.1 Definition of Flat Fee Payments
2.5.6.2 Flat Fee Variable Descriptions
2.5.6.2.1 Flat Fee ID (FFEEIDX)
2.5.6.2.2 Flat Fee Type (FFERTYPE)
2.5.6.2.3 Counts of Flat Fee Events that Cross Years
(FFBEF05, FFTOT06) C-10
2.5.6.3 Caveats of Flat Fee Groups
2.5.7 Expenditure Data
2.5.7.1 Definition of Expenditures
2.5.7.2 Data Editing and Imputation Methodologies of
Expenditure Variables
2.5.7.2.1 General Data Editing Methodology
2.5.7.2.2 General Hot-Deck Imputation
2.5.7.2.3 Emergency Room Visit Data Editing and Imputation
2.5.7.3 Imputation Flag (IMPFLAG)
2.5.7.4 Flat Fee Expenditures
2.5.7.5 Zero Expenditures
2.5.7.6 Discount Adjustment Factor
2.5.7.7 Emergency Room/Hospital Inpatient Stay
Expenditures
2.5.7.8 Sources of Payment
2.5.7.9 Imputed Emergency Room Expenditure Variables
2.5.7.9.1 Emergency Room Facility Expenditures
(ERFSF05X-ERFOT05X, ERFXP05X, ERFTC05X)
2.5.7.9.2 Emergency Room Physician Expenditures (ERDSF05X
- ERDOT05X, ERDXP05X, ERDTC05X)
2.5.7.9.3 Total Expenditures and Charges for Emergency
Room Visits (ERXP05X, ERTC05X)
2.5.8 Rounding
3.0 Sample Weight (PERWT05F)
3.1 Overview
3.2 Details on Person Weight Construction
3.2.1 MEPS Panel 9 Weight
3.2.2 MEPS Panel 10 Weight
3.2.3 The Final Weight for 2005
3.2.4 Coverage
3.3 Using MEPS Data for Trend Analysis
4.0 Strategies for Estimation
4.1 Developing Event-Level Estimates
4.2 Person-Based Estimates for Emergency Room Visits
4.3 Variables with Missing Values
4.4 Variance Estimation (VARSTR, VARPSU)
5.0 Merging/Linking MEPS Data Files
5.1 Linking to the Person-Level File
5.2 Linking to the Prescribed Medicines File
5.3 Linking to the Medical Conditions File
5.4 Pooling Annual Files
5.5 Longitudinal Analysis
References
D. Variable-Source Crosswalk
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:
No one is to use the data in this data set in any way
except for statistical reporting and analysis; and
-
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
-
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.
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
non-institutionalized 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, which includes 5 Rounds of
interviews covering 2 full calendar years, provides 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 non-institutionalized population and reflects an oversample
of blacks and Hispanics. MEPS oversamples additional policy relevant sub-groups
such as Asians and low income households. The linkage of the MEPS to the
previous year's NHIS provides additional data for longitudinal analytic
purposes.
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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 can not accurately provide. This part of the MEPS is called the
Medical Provider Component (MPC) and information is collected on dates of visit,
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 date filled and sources and
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. 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 of summary
reports, micro data files, and tables via the MEPS Web site: www.meps.ahrq.gov. Selected data can be analyzed through MEPSnet, an on-line
interactive tool designed to give data users the capability to statistically
analyze MEPS data in a menu-driven environment.
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, 540 Gaither
Road, Rockville, MD 20850 (301-427-1406).
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C. Technical and Programming Information
1.0 General Information
This documentation describes one in a series of public use
event files from the 2005 Medical Expenditure Panel Survey (MEPS) Household
Component (HC) and Medical Provider Component (MPC). Released as an ASCII data
file (with related SAS and SPSS programming statements) and a SAS
transport file, the 2005 Emergency Room Visits (EROM) public use event file
provides detailed information on emergency room visits for a nationally
representative sample of the civilian noninstitutionalized population of the
United States. Data from the EROM event file can be used to make estimates of
emergency room utilization and expenditures for calendar year 2005. The file
contains 71 variables and has a logical record length of 347 with an additional
2-byte carriage return/line feed at the end of each record. As illustrated
below, this file consists of MEPS survey data from the 2005 portion of Round 3,
and Rounds 4 and 5 for Panel 9, as well as Rounds 1, 2, and the 2005 portion of
Round 3 for Panel 10 (i.e., the rounds for the MEPS panels covering calendar
year 2005).
Emergency room events reported in Panel 10 Round 3 and
known to have occurred after December 31, 2005 are not included on this file. In
addition to expenditures, each record contains household reported medical
conditions and procedures associated with the emergency room visit.
Annual counts of emergency room visits are based entirely
on household reports. Information from the MEPS MPC is used to supplement
expenditure and payment data reported by the household and does not affect use
estimates.
Data from the Emergency Room event file can be merged with
other 2005 MEPS HC data files for purposes of appending person-level data such
as demographic characteristics or health insurance coverage to each emergency
room record.
This file can also be used to construct summary variables
of expenditures, sources of payment, and related aspects of emergency room
visits. Aggregate annual person-level information on the use of emergency rooms
and other health services use is provided on the MEPS 2005 Full Year
Consolidated Data File, where each record represents a MEPS sampled person.
This documentation offers an overview of the types and
levels of data provided, and the content and structure of the file and the
codebook. It contains the following sections:
Data File Information
Sample Weights
Strategies for Estimation
Merging/Linking MEPS Data Files
References
Variable - Source Crosswalk
Any variables not found on this file but released on
previous years’ files were excluded because they contained only missing data.
For more information on MEPS HC survey design see S.
Cohen, 1997; J. Cohen, 1997; and S. Cohen, 1996. For information on the MEPS MPC
design, see S. Cohen, 1998. Copies of the HC and the MPC survey
instruments used to collect the information on the EROM file are available in
the Survey Instrument section of the MEPS Web site at the following
address: www.meps.ahrq.gov.
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2.0 Data File Information
The 2005 Emergency Room Visits public use data set
consists of one event-level data file. The file contains characteristics
associated with the EROM event and imputed expenditure data.
The 2005 EROM public use data set contains variables and
frequency distributions for 6,446 emergency room visits reported during the 2005
portion of Round 3 and Rounds 4 and 5 for Panel 9, as well as Rounds 1, 2, and
the 2005 portion of Round 3 for Panel 10 of the MEPS Household Component. This
file includes emergency room visit records for all household survey respondents
who resided in eligible responding households and reported at least one
emergency room visit. Records where the emergency room visit was known to have
occurred after December 31, 2005 are not included on this file. Of these 6,446
records, 6,215 were associated with persons having positive person-level weights
(PERWT05F). The persons represented on this file had to meet either (a) or (b):
-
Be classified as a key in-scope person who
responded for his or her entire period of 2005 eligibility (i.e.,
persons with a positive 2005 full-year person-level weight (PERWT05F >
0)), or
-
Be an eligible member of a family all of
whose key in-scope members have a positive person-level weight
(PERWT05F > 0). (Such a family consists of all persons with the same
value for FAMIDYR.) That is, the person must have a positive full-year
family-level weight (FAMWT05F >0). Note that FAMIDYR and FAMWT05F are
variables on the 2005 Population Characteristics file.
Persons with no emergency room visit events for 2005 are
not included on this event-level ER file but are represented on the person-level
2005 Full Year Population Characteristics file. Each emergency room visit record includes the following:
date of the visit; whether or not person saw doctor; type of care received; type
of services (i.e., lab test, sonogram or ultrasound, x-rays, etc.) received;
medicines prescribed during the visit; flat fee information; imputed sources of
payment; total payment and total charge; a full-year person-level weight;
variance strata; and variance PSU.
Data from this file can be merged with the MEPS 2005 Full
Year Population Characteristics File using the person identifier, DUPERSID, to
append person-level information, such as demographic or health insurance
characteristics, to each record. Emergency room visit events can also be linked
to the MEPS 2005 Medical Conditions File and the MEPS 2005 Prescribed Medicines
File. Please see Section 5.0 and the 2005 Appendix File, HC-094I for details on
how to merge MEPS data files.
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2.1 Codebook Structure
For each variable on the Emergency Room Events event file,
both weighted and unweighted frequencies are provided in the accompanying
codebook. The codebook and data file sequence list variables in the
following order:
Unique person identifiers
Unique emergency room event identifiers
Emergency room characteristic variables
ICD-9-CM condition and procedure codes
Clinical Classification Software (CCS) codes
Imputed expenditure variables
Weight and variance estimation variables
Note that the person identifier is unique within this data
year. See the section on pooling annual files, 5.4, for details.
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2.2 Reserved Codes
The following reserved code values are used:
Value |
Definition |
-1 INAPPLICABLE |
Question was not asked due to skip pattern. |
-7 REFUSED |
Question was asked and respondent refused to answer question. |
-8 DK |
Question was asked and respondent did not know answer. |
-9 NOT ASCERTAINED |
Interviewer did not record the data. |
Generally, values of -1, -7, -8, and -9 for
non-expenditure variables have not been edited on this file. The values of -1
and -9 can be edited by the data users/analysts by following the skip patterns
in the HC survey questionnaire (located on the MEPS Web site: www.meps.ahrq.gov/survey_comp/survey_questionnaires.jsp).
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2.3 Codebook Format
The EROM codebook describes an ASCII data set (although
the data are also being provided in a SAS transport file). The following
codebook items are provided for each variable:
Identifier |
Description |
Name |
Variable name (maximum of 8 characters) |
Description |
Variable descriptor (maximum of 40 characters) |
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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2.4 Variable Source and Naming Conventions
In general, variable names reflect the content of the
variable, with an eight-character limitation. All imputed/edited variables end
with an "X".
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2.4.1 General
Variables on this file were derived from the HC
questionnaire itself, derived from the MPC data collection instrument, derived
from CAPI, or assigned in sampling. The source of each variable is identified in
Section D "Variable - Source Crosswalk" in one of four ways:
-
Variables derived from CAPI or assigned in sampling
are indicated as "CAPI derived" or "Assigned in sampling," respectively;
Variables which come from one or more specific
questions have those questionnaire sections and question numbers indicated
in the "Source" column; questionnaire sections are identified as:
-
Variables constructed from multiple questions using
complex algorithms are labeled "Constructed" in the "Source" column; and
Variables which have been edited or imputed are so
indicated.
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2.4.2 Expenditure and Source of Payment
Variables
The names of the expenditure and source of payment
variables follow a standard convention, are eight characters in length, and end
in an "X" indicating edited/imputed. Please note that imputed means that a
series of logical edits, as well as an imputation process to account for missing
data, have been performed on the variable.The total sum of payments and the 12 source of payment
variables are named in the following way:
The first two characters indicate the type of event:
IP - inpatient stay |
OB - office-based visit |
ER - emergency room visit |
OP - outpatient visit |
HH - home health visit |
DV - dental visit |
OM - other medical equipment |
RX - prescribed medicine |
For expenditure variables on the ER file, the third
character indicates whether the expenditure is associated with the facility (F)
or the physician (D).
In the case of the source of payment variables, the fourth
and fifth characters indicate:
SF - self or family |
OF - other Federal Government |
MR - Medicare |
SL - State/local government |
MD - Medicaid |
WC - Workers’ Compensation |
PV - private insurance |
OT - other insurance |
VA - Veterans |
OR - other private |
TR - TRICARE/CHAMPVA |
OU - other public |
|
XP - sum of payments |
In addition, the total charge variable is indicated by TC
in the variable name.The sixth and seventh characters indicate the year (05).
The eighth character, "X", indicates whether the variable is edited/imputed.
For example, ERFSF05X is the edited/imputed amount paid by
self or family for the facility portion of the expenditure associated with an
emergency room visit.
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2.5 File Contents
2.5.1 Survey Administration Variables
2.5.1.1 Person Identifiers (DUID, PID, DUPERSID)
The dwelling unit ID (DUID) is a five-digit random number
assigned after the case was sampled for MEPS. The three-digit person number (PID)
uniquely identifies each person within the dwelling unit. The eight-character
variable DUPERSID uniquely identifies each person represented on the file and is
the combination of the variables DUID and PID. For detailed information on
dwelling units and families, please refer to the documentation for the 2005 Full
Year Population Characteristics File.
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2.5.1.2 Record Identifiers (EVNTIDX, ERHEVIDX, FFEEIDX)
EVNTIDX uniquely identifies each emergency room
visit/event (i.e., each record on the Emergency Room visit file) and is the
variable required to link emergency room events to data files containing details
on conditions and/or prescribed medicines (MEPS 2005 Medical Conditions File and
the MEPS 2005 Prescribed Medicines File, respectively). For details on linking,
see Section 5.0 or the MEPS 2005 Appendix File, HC-094I.ERHEVIDX is a constructed variable identifying an EROM
record that has its facility expenditures represented on an associated hospital
inpatient stay record. This variable is derived from
provider-reported information on linked emergency room and inpatient stay events
that matched to corresponding events reported by the household. The variable
ERHEVIDX contains the EVNTIDX of the linked event. On the 2005 EROM file, there
are 540 emergency room events linked to subsequent hospital stays. Please note
that where the emergency room visit is associated with a hospital stay (and its
expenditures and charges are included with the hospital stay), the physician
expenditures associated with the emergency room visit remain on the Emergency
Room file.
FFEEIDX is a constructed variable which uniquely
identifies a flat fee group, that is, all events that were a part of a flat fee
payment.
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2.5.1.3 Round Indicator (EVENTRN)
EVENTRN indicates the round in which the emergency room
visit was reported. Please note: Rounds 3, 4, and 5 are associated with MEPS
survey data collected from Panel 9. Likewise, Round 1, 2, and 3 are associated
with data collected from Panel 10.
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2.5.1.4 Panel Indicator (PANEL)
PANEL is a constructed variable used to specify the panel
number for the person. PANEL will indicate either Panel 9 or Panel 10 for each
person on the file. Panel 9 is the panel that started in 2004, and Panel 10 is
the panel that started in 2005.
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2.5.2 MPC Data Indicator (MPCDATA)
MPCDATA is a constructed variable which indicates whether
or not MPC data were collected for the emergency room visit. While all emergency
room events are sampled into the Medical Provider Component, not all emergency
room event records have MPC data associated with them. This is dependent upon
the cooperation of the household respondent to provide permission forms to
contact the emergency room facility as well as the cooperation of the emergency
room facility to participate in the survey.
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2.5.3 Emergency Room Visit Event Variables
This file contains variables describing emergency room
visits/events reported by household respondents in the Emergency Room section of
the MEPS HC questionnaire. The questionnaire contains specific probes for
determining details about the emergency room event. These variables have not
been edited.
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2.5.3.1 Visit Details (ERDATEYR-VSTRELCN)
When a person reported having had a visit to the emergency
room, the date of the emergency room visit was recorded (ERDATEYR, ERDATEMM,
ERDATEDD). Also reported is whether or not the person saw a medical doctor (SEEDOC).
The type of care the person received (VSTCTGRY) and whether or not the visit was
related to a specific condition (VSTRELCN) were also determined.
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2.5.3.2 Services, Procedures, and Prescription Medicines (LABTEST-MEDPRESC)
Services received during the visit included whether or not
the person received lab tests (LABTEST), a sonogram or ultrasound (SONOGRAM),
x-rays (XRAYS), a mammogram (MAMMOG), an MRI or CAT scan (MRI), an
electrocardiogram (EKG), an electroencephalogram (EEG), a vaccination (RCVVAC),
anesthesia (ANESTH), or other diagnostic tests or exams (OTHSVCE). Whether or
not a surgical procedure was performed during the visit was asked (SURGPROC).
The questionnaire determined if a medicine was prescribed for the person during
the emergency room visit (MEDPRESC). See Section 5.2 for information on linking
to the prescription medicine events file.
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2.5.4 VA Facility (VAPLACE)
VAPLACE is a constructed variable that indicates whether
the service was provided at a VA facility. This variable only has valid data for
providers that were sampled into the Medical Provider Component. All other
providers are classified as "No".
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2.5.5 Condition and Procedure Codes
(ERICD1X-ERICD3X, ERPRO1X, ERPRO2X), and Clinical Classification Codes
(ERCCC1X-ERCCC3X)
Information on household reported medical conditions and
procedures associated with each emergency room visit is provided on this file.
There are up to three condition and CCS codes (ERICD1X-ERICD3X, ERCCC1X-ERCCC3X)
and up to two procedure codes (ERPRO1X, ERPRO2X) listed for each emergency room
visit. In order to obtain complete condition information associated with an
event, the data user/analyst must link to the MEPS 2005 Medical Conditions File.
Details on how to link the 2005 EROM event file to the MEPS 2005 Medical
Conditions File are provided in Section 5.3 and the MEPS 2005 Appendix File,
HC-094I. The data user/analyst should note that because of
confidentiality restrictions, provider-reported condition information is not
publicly available.The medical conditions and procedures reported by the
Household Component respondent were recorded by the interviewer as verbatim
text, which were then coded to fully-specified 2005 ICD-9-CM codes, including
medical conditions and V codes (Health Care Financing Administration, 1980) by
professional coders. Although codes were verified and error rates did not exceed
2.5 percent for any coder, data users/analysts should not presume this level of
precision in the data; the ability of household respondents to report condition
data that can be coded accurately should not be assumed (Cox and Cohen, 1985;
Cox and Iachan, 1987; Edwards, et al, 1994; and Johnson and Sanchez, 1993). For
detailed information on how conditions and procedures were coded, please refer
to the documentation on the MEPS 2005 Medical Conditions File. For frequencies
of conditions by event type, please see the MEPS 2005 Appendix File, HC-094I.The ICD-9-CM condition codes were aggregated into
clinically meaningful categories. These categories, included on the file as
ERCCC1X-ERCCC3X, were generated using Clinical Classification Software [formerly
known as Clinical Classifications for Health Care Policy Research (CCHPR)], (Elixhauser,
et al., 1998), which aggregates conditions and V-codes into 263 mutually
exclusive categories, most of which are clinically homogeneous.
In order to preserve respondent confidentiality, nearly
all of the condition codes provided on this file have been collapsed from
fully-specified codes to three-digit code categories. The reported ICD-9-CM code
values were mapped to the appropriate clinical classification category prior to
being collapsed to the three-digit categories. Similarly, the procedure codes
have been collapsed from fully-specified codes to two-digit code categories.
Because of this collapsing, it is possible for there to be duplicate ICD-9-CM
condition or procedure codes linked to a single medical event when different
fully-specified codes are collapsed into the same code. For more information on
ICD-9-CM codes, see the HC-096 documentation.
The condition codes (and clinical classification codes)
and procedure codes linked to each emergency room visit are sequenced in the
order in which the conditions were reported by the household respondent, which
was in order of input into the database and not in order of importance or
severity. Data users/analysts who use the MEPS 2005 Medical Conditions File in
conjunction with this emergency room visits file should note that the order of
conditions on this file is not identical to that on the Medical Conditions file.
Analysts should use the clinical classification codes
listed in the Conditions PUF document (HC-096) and the Appendix to the Event
Files (HC-094I) document when analyzing MEPS conditions data. Although there is
a list of clinical classification codes and labels on the Healthcare Cost and
Utilization Project (HCUP) Web site, if updates to these codes and/or labels are
made on the HCUP Web site after the release of the 2005 MEPS PUFs, these updates
will not be reflected in the 2005 MEPS data.
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2.5.6 Flat Fee Variables (FFEEIDX, FFERTYPE, FFBEF05,
FFTOT06)
2.5.6.1 Definition of Flat Fee Payments
A flat fee is the fixed dollar amount a person is charged
for a package of health care services provided during a defined period of time.
Examples would be: obstetrician’s fee covering a normal delivery, as well as
pre- and post-natal care; or a surgeon’s fee covering surgical procedure and
post-surgical care. A flat fee group is the set of medical services (i.e.,
events) that are covered under the same flat fee payment. The flat fee groups
represented on this file include flat fee groups where at least one of the
health care events, as reported by the HC respondent, occurred during 2005. By
definition, a flat fee group can span multiple years. Furthermore, a single
person can have multiple flat fee groups.
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2.5.6.2 Flat Fee Variable Descriptions
2.5.6.2.1 Flat Fee ID (FFEEIDX)
As noted earlier in Section 2.5.1.2 "Record Identifiers,"
the variable FFEEIDX uniquely identifies all events that are part of the same
flat fee group for a person. On any 2005 MEPS event file, every event that is
part of a specific flat fee group will have the same value for FFEEIDX. Note
that prescribed medicine and home health events are never included in a flat fee
group and FFEEIDX is not a variable on those event files.
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2.5.6.2.2 Flat Fee Type (FFERTYPE)
FFERTYPE indicates whether the 2005 emergency room visit
is the "stem" or "leaf" of a flat fee group. A stem (records with FFERTYPE = 1)
is the initial medical service (event) which is followed by other medical events
that are covered under the same flat fee payment. The leaves of the flat fee
group (records with FFERTYPE = 2) are those medical events that are tied back to
the initial medical event (the stem) in the flat fee group. These "leaf" records
have their expenditure variables set to zero. For the emergency room visits that
are not part of a flat fee payment, the FFERTYPE is set to –1, "INAPPLICABLE."
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2.5.6.2.3 Counts of Flat Fee Events that Cross Years
(FFBEF05, FFTOT06)
As described in Section 2.5.6.1, a flat fee payment may
cover multiple events, and the multiple events could span multiple years. For
situations where the emergency room event occurred in 2005 as part of a group of
events, and some event occurred before or after 2005, counts of the known events
are provided on the emergency room record. Variables indicating events that
occurred before or after 2005 are as follows:
FFBEF05 – total number of pre-2005 events in the same
flat fee group as the 2005 emergency room visit(s). This count would not
include the 2005 emergency room visit(s).
FFTOT06 –the number of 2006 emergency room visits,
expected to be in the same flat fee group as the emergency room event that
occurred in 2005. Because there were no 2006 events expected for any flat
fee groups, this variable was omitted from the 2005 ER file.
If there are no 2004 events on the file, FFBEF05 will be
omitted. Likewise, if there are no 2006 events on the file, FFTOT06 will be
omitted. If there are no flat fee data related to the records in this file,
FFEEIDX and FFERTYPE will be omitted as well. Please note that the crosswalk in
this document lists all possible flat fee variables.
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2.5.6.3 Caveats of Flat Fee Groups
There are 24 emergency room visits that are identified as
being part of a flat fee payment group. In general, every flat fee group should
have an initial visit (stem) and at least one subsequent visit (leaf). There are
some situations where this is not true. For some flat fee groups, the initial
visit reported occurred in 2005, but the remaining visits that were part of this
flat fee group occurred in 2006. In this case, the 2005 flat fee group
represented on this file would consist of one event, the stem. The 2006 events
that are part of this flat fee group are not represented on the file. Similarly,
the household respondent may have reported a flat fee group where the initial
visit began in 2004 but subsequent visits occurred during 2005. In this case,
the initial visit would not be represented on the file. This 2005 flat fee group
would then only consist of one or more leaf records and no stem.
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2.5.7 Expenditure Data
2.5.7.1 Definition of Expenditures
Expenditures on this file refer to what is paid for health
care services. More specifically, expenditures in MEPS are defined as the sum of
payments for care received for each emergency room visit, including
out-of-pocket payments and payments made by private insurance, Medicaid,
Medicare and other sources. The definition of expenditures used in MEPS differs
slightly from its predecessors: the 1987 NMES and 1977 NMCES surveys where
"charges" rather than sum of payments were used to measure expenditures. This
change was adopted because charges became a less appropriate proxy for medical
expenditures during the 1990s due to the increasingly common practice of
discounting. Although measuring expenditures as the sum of payments incorporates
discounts in the MEPS expenditure estimates, the estimates do not incorporate
any payment not directly tied to specific medical care visits, such as bonuses
or retrospective payment adjustments by third party payers. Another general
change from the two prior surveys is that charges associated with uncollected
liability, bad debt, and charitable care (unless provided by a public clinic or
hospital) are not counted as expenditures because there are no payments
associated with those classifications. While charge data are provided on this
file, data users/analysts should use caution when working with this data because
a charge does not typically represent actual dollars exchanged for services or
the resource costs of those services; nor are they directly comparable to the
expenditures defined in the 1987 NMES. For details on expenditure definitions,
please reference "Informing American Health Care Policy" (Monheit et al., 1999).
AHRQ has developed factors to apply to the 1987 NMES expenditure data to
facilitate longitudinal analysis. These factors can be assessed via the CFACT
data center. For more information, see the data center section of the MEPS Web
site <www.meps.ahrq.gov>.
Expenditure data related to emergency room visits are
broken out by facility and separately billing doctor expenditures. This file
contains six categories of expenditure variables per visit: basic hospital
emergency room facility expenses; expenses for doctors who billed separately
from the hospital for any emergency room services provided during the emergency
room visit; total expenses, which is the sum of the facility and physician
expenses; facility charge; physician charge, and total charges, which is the sum
of the facility and physician charges. If examining trends in MEPS expenditures
or performing longitudinal analysis on MEPS expenditures please refer to Section
C, sub-Section 3.3 for more information.
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2.5.7.2 Data Editing and Imputation Methodologies of
Expenditure Variables
The expenditure data included on this file were derived
from both the MEPS Household (HC) and Medical Provider Component (MPC). The MPC
contacted medical providers identified by household respondents. The charge and
payment data from medical providers were used in the expenditure imputation
process to supplement missing household data. For all emergency room visits, MPC
data were used if available; otherwise, HC data were used. Missing data for
emergency room visits, where HC data were not complete and MPC data were not
collected, or MPC data were not complete, were imputed through the imputation
process.
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2.5.7.2.1 General Data Editing Methodology
Logical edits were used to resolve internal
inconsistencies and other problems in the HC and MPC survey-reported data. The
edits were designed to preserve partial payment data from households and
providers, and to identify actual and potential sources of payment for each
household-reported event. In general, these edits accounted for outliers,
copayments or charges reported as total payments, and reimbursed amounts that
were reported as out-of-pocket payments. In addition, edits were implemented to
correct for misclassifications between Medicare and Medicaid and between
Medicare HMOs and private HMOs as payment sources. These edits produced a
complete vector of expenditures for some events, and provided the starting point
for imputing missing expenditures in the remaining events.
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2.5.7.2.2 General Hot-Deck Imputation
A weighted sequential hot-deck procedure was used to
impute missing expenditures as well as total charge. This procedure uses survey
data from respondents to replace missing data while taking into account the
respondents’ weighted distribution in the imputation process. Classification
variables vary by event type in the hot-deck imputations, but total charge and
insurance coverage are key variables in all of the imputations. Separate
imputations were performed for nine categories of medical provider care:
inpatient hospital stays, outpatient hospital department visits, emergency room
visits, visits to physicians, visits to non-physician providers, dental
services, home health care by certified providers, home health care by paid
independents, and other medical expenses. Within each event type file, separate
imputations were performed for flat fee and simple events. After the imputations
were finished, visits to physician and non-physician providers were combined
into a single medical provider file. The two categories of home care also were
combined into a single home health file.
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2.5.7.2.3 Emergency Room Visit Data Editing and Imputation
Facility expenditures for emergency room services were
developed in a sequence of logical edits and imputations. "Household" edits were
applied to sources and amounts of payment for all events reported by HC
respondents. "MPC" edits were applied to provider-reported sources and amounts
of payment for records matched to household-reported events. Both sets of edits
were used to correct obvious errors in the reporting of expenditures. After the
data from each source were edited, a decision was made as to whether household-
or MPC-reported information would be used in the final editing and hot-deck
imputations for missing expenditures. The general rule was that MPC data would
be used where a household-reported event corresponded to an MPC-reported event
(i.e., a matched event), since providers usually have more complete and accurate
data on sources and amounts of payment than households.One of the more important edits separated flat fee events
from simple events. This edit was necessary because groups of events covered by
a flat fee (i.e., a flat fee bundle) were edited and imputed separately from
individual events covered by a single charge (i.e., simple events). Most
emergency room events were imputed as simple events because hospital facility
charges are rarely bundled with other events. (See Section 2.5.6 for more
details on flat fee groups). However, some emergency room visits were treated as
free events because the respondent was admitted to a hospital through its
emergency room. In these cases, emergency room charges are included in the
charge for an inpatient hospital stay.Logical edits also were used to sort each event into a
specific category for the imputations. Events with complete expenditures were
flagged as potential donors for the hot-deck imputations, while events with
missing expenditure data were assigned to various recipient categories. Each
event with missing expenditure data was assigned to a recipient category based
on the extent of its missing charge and expenditure data. For example, an event
with a known total charge but no expenditure information was assigned to one
category, while an event with a known total charge and partial expenditure
information was assigned to a different category. Similarly, events without a
known total charge and no or partial expenditure information were assigned to
various recipient categories. The logical edits produced eight recipient categories in
which all events had a common extent of missing data. Separate hot-deck
imputations were performed on events in each recipient category. For hospital
inpatient and emergency room
events, the donor pool was restricted to events with complete
expenditures from the MPC. Due to the low ratio of donors to recipients for
hospital outpatient and office-based events,
there were no donor pool restrictions.The donor pool included "free events" because, in some
instances, providers are not paid for their services. These events represent
charity care, bad debt, provider failure to bill, and third party payer
restrictions on reimbursement in certain circumstances. If free events were
excluded from the donor pool, total expenditures would be over-counted because
the distribution of free event among complete events (donors) would not be
represented among incomplete events (recipients).Expenditures for some emergency room visits are not shown
because the person was admitted to the hospital through the emergency room.
These emergency room events are not free, but the expenditures are included in
the inpatient stay expenditures. The variable ERHEVIDX can be used to
differentiate between free emergency room care and situations where the
emergency room charges have been included in the inpatient hospital charges.
Expenditures for services provided by separately billing
doctors in hospital settings were also edited and imputed. These expenditures
are shown separately from hospital facility charges for hospital inpatient,
outpatient, and emergency room care.
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2.5.7.3 Imputation Flag (IMPFLAG)
IMPFLAG is a six-category variable that indicates if the
event contains complete Household Component (HC) or Medical Provider Component (MPC)
data, was fully or partially imputed, or was imputed in the capitated imputation
process (for OP and MV events only). The following list identifies how the
imputation flag is coded; the categories are mutually exclusive.
IMPFLAG=0 not eligible for imputation (includes zeroed out and flat fee leaf events)
IMPFLAG=1 complete
HC data
IMPFLAG=2 complete MPC data
IMPFLAG=3 fully imputed
IMPFLAG=4 partially imputed
IMPFLAG=5 complete MPC data through capitation imputation (not applicable to ER events)
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2.5.7.4 Flat Fee Expenditures
The approach used to count expenditures for flat fees was
to place the expenditure on the first visit of the flat fee group. The remaining
visits have zero facility payments, while physician’s expenditures may be still
present. Thus, if the first visit in the flat fee group occurred prior to 2005,
all of the events that occurred in 2005 will have zero payments. Conversely, if
the first event in the flat fee group occurred at the end of 2005, the total
expenditure for the entire flat fee group will be on that event, regardless of
the number of events it covered after 2005. See Section 2.5.6 for details on the
flat fee variables.
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2.5.7.5 Zero Expenditures
There are some medical events reported by respondents
where the payments were zero. Zero payment events can occur in MEPS for the
following reasons: (1) the stay was covered under a flat fee arrangement
(flat fee payments are included only on the first event covered by the
arrangement), (2) there was no charge for a follow-up stay, (3) the provider was
never paid by an individual, insurance plan, or other source for services
provided, (4) charges were included in the bill for a subsequent hospital
admission (emergency room events only), or (5) the event was paid for through
government or privately-funded research or clinical trials.
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2.5.7.6 Discount Adjustment Factor
An adjustment was also applied to some HC-reported
expenditure data because an evaluation of matched HC/MPC data showed that
respondents who reported that charges and payments were equal were often unaware
that insurance payments for the care had been based on a discounted charge. To
compensate for this systematic reporting error, a weighted sequential hot-deck
imputation procedure was implemented to determine an adjustment factor for
HC-reported insurance payments when charges and payments were reported to be
equal. As for the other imputations, selected predictor variables were used to
form groups of donor and recipient events for the imputation process.
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2.5.7.7 Emergency Room/Hospital Inpatient Stay
Expenditures
It is common for an emergency room visit to result in a
hospital stay. While it is true that all of the event files can be linked by
DUPERSID, there is no unique record link between hospital inpatient stays and
emergency room visits. However, wherever this relationship could be identified
(using the MPC start and end dates of the events as well as other information
from the provider), the facility expenditure associated with the emergency room
visit is included in the hospital facility expenditure. Hence, the expenditures
(and charges) for some emergency room visits are included in the resulting
hospitalization. In these situations, the emergency room record on this file
will have its expenditure (and charge) information zeroed out to avoid
double-counting while its corresponding hospital inpatient stay record on the
MEPS 2005 Hospital Inpatient Stays File will have the combined expenditures.
Please note that any physician expenditures associated with emergency room
events remain on the Emergency Room event file. The variable ERHEVIDX identifies
the emergency room visits whose facility expenditures are included in the
expenditures for the following hospital inpatient stay. It should also be noted
that for these cases there is only one emergency room stay associated with the
hospital room stay.
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2.5.7.8 Sources of Payment
In addition to total expenditures, variables are provided
which itemize expenditures according to major source of payment categories.
These categories are:
- Out-of-pocket by user or family,
- Medicare,
- Medicaid,
- Private Insurance,
- Veterans Administration, excluding TRICARE/CHAMPVA,
- TRICARE/CHAMPVA,
- Other Federal sources - includes Indian Health Service,
Military Treatment Facilities, and other care by the Federal government,
- Other State and Local Source - includes community
and neighborhood clinics, State and local health departments, and State
programs other than Medicaid,
- Workers’ Compensation, and
- Other Unclassified Sources - includes sources such
as automobile, homeowner’s, and liability insurance, and other
miscellaneous or unknown sources.
Two additional source of payment variables were created to
classify payments for events with apparent inconsistencies between health
insurance coverage and sources of payment based on data collected in the survey.
These variables include:
Other Private - any type of private insurance
payments reported for persons not reported to have any private health
insurance coverage during the year as defined in MEPS, and
Other Public – Medicare/Medicaid payments reported
for persons who were not reported to be enrolled in the
Medicare/Medicaid program at any time during the year.
Though these two sources are relatively small in
magnitude, data users/analysts should exercise caution when interpreting the
expenditures associated with these two additional sources of payment. While
these payments stem from apparent inconsistent responses to health insurance and
source of payment questions in the survey, some of these inconsistencies may
have logical explanations. For example, private insurance coverage in MEPS is
defined as having a major medical plan covering hospital and physician services.
If a MEPS sampled person did not have such coverage but had a single service
type insurance plan (e.g., dental insurance) that paid for a particular episode
of care, those payments may be classified as "other private." Some of the "other
public" payments may stem from confusion between Medicaid and other state and
local programs or may be from persons who were not enrolled in Medicaid, but
were presumed eligible by a provider who ultimately received payments from the
public payer.
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2.5.7.9 Imputed Emergency Room Expenditure Variables
This file contains two sets of imputed expenditure
variables: facility expenditures and physician expenditures.
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2.5.7.9.1 Emergency Room Facility Expenditures
(ERFSF05X-ERFOT05X, ERFXP05X, ERFTC05X)
Emergency room expenses include all expenses for
treatment, services, tests, diagnostic and laboratory work, x-rays, and similar
charges, as well as any physician services included in the emergency room
charge.
ERFSF05X - ERFOT05X are the 12 sources of payment. The 12
sources of payment are: self/family (ERFSF05X), Medicare (ERFMR05X), Medicaid
(ERFMD05X), private insurance (ERFPV05X), Veterans Administration (ERFVA05X),
TRICARE/CHAMPVA (ERFTR05X), other Federal sources (ERFOF05X), State and Local
(non-federal) government sources (ERFSL05X), Worker’s Compensation (ERFWC05X),
other private insurance (ERFOR05X), other public insurance (ERFOU05X), and other
insurance (ERFOT05X). ERFXP05X is the sum of the 12 sources of payment for the
Emergency Room expenditures, and ERFTC05X is the total charge. Please note that
where an emergency room visit record is linked to a hospital inpatient stay
record, all facility sources of payment variables, as well as ERFTC05X, have
been zeroed out.
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2.5.7.9.2 Emergency Room Physician Expenditures (ERDSF05X
- ERDOT05X, ERDXP05X, ERDTC05X)
Separately billing doctor (SBD) expenses typically cover
services provided to patients in hospital settings by providers like
anesthesiologists, radiologists, and pathologists, whose charges are often not
included in emergency room visit bills.
For physicians who bill separately (i.e., outside the
emergency room visit bill), a separate data collection effort within the Medical
Provider Component was performed to obtain this same set of expenditure
information from each separately billing doctor. It should be noted that there
could be several separately billing doctors associated with a medical event. For
example, an emergency room visit could have a radiologist and an internist
associated with it. If their services are not included in the emergency room
visit bill then this is one medical event with two separately billing doctors.
The imputed expenditure information associated with the separately billing
doctors was summed to the event level and is provided on the file. ERDSF05X -
ERDOT05X are the 12 sources of payment, ERDXP05X is the sum of the 12 sources of
payments, and ERDTC05X is the physician’s total charge.
Data users/analysts need to take into consideration
whether to analyze facility and SBD expenditures separately, combine them within
service categories, or collapse them across service categories (e.g., combine
SBD expenditures with expenditures for physician visits to offices and/or
outpatient departments).
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2.5.7.9.3 Total Expenditures and Charges for Emergency
Room Visits (ERXP05X, ERTC05X)
Data users/analysts interested in total expenditure should
use the variable ERXP05X, which includes both the facility and physician
amounts. Those interested in total charges should use the variable ERTC05X,
which includes both facility and physician charges (see Section 2.5.7.1 for an
explanation of the "charge" concept). However, please note that where the
emergency room visit is linked to a hospital inpatient stay record, ERFTC05X has
been zeroed out. Thus, ERTC05X may be equal to "0" or the doctor total charge
(ERDTC05X).
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2.5.8 Rounding
The expenditure variables have been rounded to the nearest
penny. Person-level expenditure information released on the MEPS 2005 Person
Level Use and Expenditure File were rounded to the nearest dollar. It should be
noted that using the MEPS 2005 event files to create person-level totals will
yield slightly different totals than those found on the person-level expenditure
file. These differences are due to rounding only. Moreover, in some instances,
the number of persons having expenditures on the event files for a particular
source of payment may differ from the number of persons with expenditures on the
person-level expenditures file for that source of payment. This difference is
also an artifact of rounding only. Please see the MEPS 2005 Appendix File,
HC-094I, for details on such rounding differences.
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3.0 Sample Weight (PERWT05F)
3.1 Overview
There is a single full year person-level weight (PERWT05F)
assigned to each record for each key, in-scope person who responded to MEPS for
the full period of time that he or she was in-scope during 2005. A key person
either was a member of an NHIS household at the time of the NHIS interview, or
became a member of a family associated with such a household after being
out-of-scope at the time of the NHIS (the latter circumstance includes newborns
as well as persons returning from military service, an institution, or living
outside the United States). A person is in-scope whenever he or she is a member
of the civilian noninstitutionalized portion of the U.S. population.
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3.2 Details on Person Weight Construction
The person-level weight PERWT05F was developed in several
stages. Person-level weights for Panels 9 and 10 were created separately. The
weighting process for each panel included an adjustment for nonresponse over
time and calibration to independent population figures. The calibration was
initially accomplished separately for each panel by raking the corresponding
sample weights to Current Population Survey (CPS) population estimates based on
five variables. The five variables used in the establishment of the initial
person-level control figures were: census region (Northeast, Midwest, South,
West); MSA status (MSA, non-MSA); race/ethnicity (Hispanic, non-Hispanic with
black as sole reported race, non-Hispanic with Asian as sole reported race, and
other); sex; and age. A 2005 composite weight was then formed by multiplying
each weight from Panel 9 by the factor .5 and each weight from Panel 10 by the
factor .5. The choice of factors reflected the relative sample sizes of the two
panels, helping to limit the variance of estimates obtained from pooling the two
samples. The composite weight was again raked to the same set of CPS-based
control totals. When poverty status information derived from income variables
became available, a final raking was undertaken on the previously established
weight variable. Control totals were established using poverty status (five
categories: below poverty, from 100 to 125 percent of poverty, from 125 to 200
percent of poverty, from 200 to 400 percent of poverty, at least 400 percent of
poverty) as well as the original five variables used in the previous
calibrations.
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3.2.1 MEPS Panel 9 Weight
The person-level weight for MEPS Panel 9 was developed
using the 2004 full year weight for an individual as a "base" weight for survey
participants present in 2004. For key, in-scope respondents who joined an RU
some time in 2005 after being out-of-scope in 2004, the 2004 family weight
associated with the family the person joined served as a "base" weight. The
weighting process included an adjustment for nonresponse over Rounds 4 and 5 as
well as raking to population control figures for December 2005. These control
figures were derived by scaling back the population totals obtained from the
March 2005 CPS to correspond to a national estimate for the civilian
noninstitutionalized population provided by the Census Bureau for December 2005.
Variables used in the establishment of person-level control figures included:
census region (Northeast, Midwest, South, West); MSA status (MSA, non-MSA);
race/ethnicity (Hispanic, black but non-Hispanic, Asian but non-Hispanic, and
other); sex; and age. Overall, the weighted population estimate for the civilian
noninstitutionalized population on December 31, 2005 is 292,372,718. Key,
responding persons not in-scope on December 31, 2005 but in-scope earlier in the
year retained, as their final Panel 9 weight, the weight after the nonresponse
adjustment.
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3.2.2 MEPS Panel 10 Weight
The person-level weight for MEPS Panel 10 was developed
using the MEPS Round 1 person-level weight as a "base" weight. For key, in-scope
respondents who joined an RU after Round 1, the Round 1 family weight served as
a "base" weight. The weighting process included an adjustment for nonresponse
over Round 2 and the 2005 portion of Round 3 as well as raking to the same
population control figures for December 2005 used for the MEPS Panel 9 weights.
The same five variables employed for Panel 9 raking (census region, MSA status,
race/ethnicity, sex, and age) were used for Panel 10 raking. Similarly, for
Panel 10, key, responding persons not in-scope on December 31, 2005 but in-scope
earlier in the year retained, as their final Panel 10 weight, the weight after
the nonresponse adjustment.
Note that the MEPS Round 1 weights (for both panels with
one exception as noted below) incorporated the following components: the
original household probability of selection for the NHIS; ratio-adjustment to
NHIS-based national population estimates at the household (occupied dwelling
unit) level; adjustment for nonresponse at the dwelling unit level for Round 1;
and poststratification to figures at the family and person level obtained from
the March 2005 CPS data base.
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3.2.3 The Final Weight for 2005
Variables used in the establishment of person-level
control figures included: poverty status (below poverty, from 100 to 125 percent
of poverty, from 125 to 200 percent of poverty, from 200 to 400 percent of
poverty, at least 400 percent of poverty); census region (Northeast, Midwest,
South, West); MSA status (MSA, non-MSA); race/ethnicity (Hispanic, non-Hispanic
with black as sole reported race, non-Hispanic with Asian as sole reported race,
and other); sex; and age. Overall, the weighted population estimate for the
civilian noninstitutionalized population for December 31, 2005 is 292,372,718
(PERWT05F>0 and INSC1231=1). The weights of some persons out-of-scope on
December 31, 2005 were also calibrated, this time using poststratification.
Specifically, the weights of persons out-of-scope on December 31, 2005 who were
in-scope some time during the year and also entered a nursing home during the
year were poststratified to a corresponding control total obtained from the 1996
MEPS Nursing Home Component. The weights of persons who died while in-scope
during 2005 were poststratified to corresponding estimates derived using data
obtained from the Medicare Current Beneficiary Survey (MCBS) and Vital
Statistics information provided by the National Center for Health Statistics (NCHS).
Separate control totals were developed for the "65 and older" and "under 65"
civilian noninstitutionalized populations. The sum of the person-level weights
across all persons assigned a positive person level weight is 292,372,718.
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3.2.4 Coverage
The target population for MEPS in this file is the 2005
U.S. civilian noninstitutionalized population. However, the MEPS sampled
households are a subsample of the NHIS households interviewed in 2003 (Panel 9)
and 2004 (Panel 10). New households created after the NHIS interviews for the
respective Panels and consisting exclusively of persons who entered the target
population after 2003 (Panel 9) or after 2004 (Panel 10) are not covered by
MEPS. Neither are previously out-of-scope persons who join an existing household
but are unrelated to the current household residents. Persons not covered by a
given MEPS panel thus include some members of the following groups: immigrants;
persons leaving the military; U.S. citizens returning from residence in another
country; and persons leaving institutions. The set of uncovered persons
constitutes only a small segment of the MEPS target population.
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3.3 Using MEPS Data for Trend Analysis
MEPS began in 1996, and the utility of the survey for
analyzing health care trends expands with each additional year of data. However,
it is important to consider a variety of factors when examining trends over time
using MEPS. Statistical significance tests should be conducted to assess the
likelihood that observed trends may be attributable to sampling variation. The
length of time being analyzed should also 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. Looking at changes over longer
periods of time can provide a more complete picture of underlying trends.
Analysts may wish to consider using techniques to smooth or stabilize analyses
of trends using MEPS data such as comparing pooled time periods (e.g. 1996-97
versus 2004-05), 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, 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 inappropriately concluding that a change has taken
place.
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4.0 Strategies for Estimation
4.1 Developing Event-Level Estimates
The data in this file can be used to develop national 2005
event level estimates for the U.S. civilian noninstitutionalized population on
emergency room visits as well as expenditures, and sources of payment for these
visits. Estimates of total visits are the sum of the weight variable (PERWT05F)
across relevant event records while estimates of other variables must be
weighted by PERWT05F to be nationally representative. The tables below contain
event-level estimates for selected variables.
Selected Event Level Estimates
Emergency Room Visits
Estimate of Interest |
Variable Name |
Estimate (SE) |
Estimate (SE)
Excluding 0s |
Total number of emergency room
visits (in millions) |
PERWT05F |
55.0 (1.76) |
50.6 (1.60) |
Proportion of emergency room
visits with expenditures > 0 * |
ERXP05X |
0.920 (0.0052) |
-------- |
Emergency Room Expenditures
Estimate of Interest |
Variable Name |
Estimate (SE) |
Estimate (SE)
Excluding 0s |
Mean total payments per visit |
ERxp05x |
$606 ($18.2) |
$659 ($19.1) |
Mean out-of-pocket payment per
visit |
ERDsf05x
+ERFSF05X |
$69 ($6.9) |
$75 ($7.5) |
Mean proportion of total
expenditures paid by private
insurance per visit |
(ERDpv05x+
ERFPV05X)
/ERxp05x |
------- |
0.393 (0.0109) |
Emergency Room Expenditures: Physician Visits (SEEDOC =
1 )
Estimate of Interest |
Variable Name |
Estimate (SE) |
Estimate (SE)
Excluding 0s |
Mean total payments per visit
where person saw medical doctor |
ERxp05x |
$604 ($17.0) |
$657 ($17.8) |
Mean out-of-pocket payment per
visit where person saw medical
doctor |
ERDsf05x
+ERFSF05X |
$68 ($7.1) |
$74 ($7.8) |
Mean proportion of total
expenditures per visit paid by
private insurance where person
saw medical doctor |
(ERDpv05x+
ERFPV05X)
/ERxp05x |
------- |
0.392 (0.0109) |
* Zero payment events can occur in MEPS for the following
reasons: (1) the stay was covered under a flat fee arrangement (flat fee
payments are included only on the first event covered by the arrangement), (2)
there was no charge for a follow-up stay, (3) the provider was never paid by an
individual, insurance plan, or other source for services provided, or (4)
charges were included in the bill for a subsequent hospital admission (emergency
room events only), or (5) the event was paid for through government or
privately-funded research or clinical trials.
Return To Table Of Contents
4.2 Person-Based Estimates for Emergency Room Visits
To enhance analyses of emergency room visits, analysts may
link information about emergency room visits by sample persons in this file to
the annual full year consolidated file (which has data for all MEPS sample
persons), or conversely, link person-level information from the full year
consolidated file to this event level file (see Section 5 below for more
details). Both this file and the full year consolidated file may be used to
derive estimates for persons with emergency room care and annual estimates of
total expenditures. However, if the estimate relates to the entire population,
this file cannot be used to calculate the denominator, as only those persons
with at least one emergency room event are represented on this data file.
Therefore, the full year consolidated file must be used for person-level
analyses that include both persons with and without emergency room care.
Return To Table Of Contents
4.3 Variables with Missing Values
It is essential that the analyst examine all variables for
the presence of negative values used to represent missing values. For continuous
or discrete variables, where means or totals may be taken, it may be necessary
to set negative values to values appropriate to the analytic needs. That is, the
analyst should either impute a value or set the value to one that will be
interpreted as missing by the computing language used. For categorical and
dichotomous variables, the analyst may want to consider whether to recode or
impute a value for cases with negative values or whether to exclude or include
such cases in the numerator and/or denominator when calculating proportions.
Methodologies used for the editing/imputation of expenditure variables (e.g.,
sources of payment, flat fee, and zero expenditures) are described in Section
2.5.7.
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4.4 Variance Estimation (VARPSU, VARSTR)
MEPS has a complex sample design. To obtain estimates of
variability (such as the standard error of sample estimates or corresponding
confidence intervals) for MEPS estimates, analysts need to take into account the
complex sample design of MEPS for both person-level and family-level analyses.
Several methodologies have been developed for estimating standard errors for
surveys with a complex sample design, including the Taylor-series linearization
method, balanced repeated replication, and jackknife replication. Various
software packages provide analysts with the capability of implementing these
methodologies. Replicate weights have not been developed for the MEPS data.
Instead, the variables needed to calculate appropriate standard errors based on
the Taylor-series linearization method are included on this file as well as all
other MEPS public use files. Software packages that permit the use of the
Taylor-series linearization method include SUDAAN, Stata, SAS (version 8.2 and
higher), and SPSS (version 12.0 and higher). For complete information on the
capabilities of each package, analysts should refer to the corresponding
software user documentation.
Using the Taylor-series linearization method, variance
estimation strata and the variance estimation PSUs within these strata must be
specified. The variance strata variable is named VARSTR, while the variance PSU
variable is named VARPSU. Specifying a "with replacement" design in a computer
software package, such as SUDAAN, provides standard errors appropriate for
assessing the variability of MEPS survey estimates. It should be noted that the
number of degrees of freedom associated with estimates of variability indicated
by such a package may not appropriately reflect the actual number available. For
MEPS sample estimates for characteristics generally distributed throughout the
country (and thus the sample PSUs), one can expect at least 100 degrees of
freedom for the 2005 full year data associated with the corresponding estimates
of variance.
Prior to 2002, MEPS variance strata and PSUs were
developed independently from year to year, and the last two characters of the
strata and PSU variable names denoted the year. However, beginning with the 2002
Point-in-Time PUF, the variance strata and PSUs were developed to be compatible
with MEPS data associated with the NHIS sample design used through 2005. Such
data can be pooled and the variance strata and PSU variables provided can be
used without modification for variance estimation purposes for estimates
covering multiple years of data. There are 203 variance estimation strata, each
stratum with either two or three variance estimation PSUs.
Note: A new NHIS sample design is being implemented
beginning in 2006. As a result, the MEPS variance estimation structure will be
modified for MEPS data collected in 2007 and beyond.
Return To Table Of Contents
5.0 Merging/Linking MEPS Data Files
Data from this file can be used alone or in conjunction
with other files for different analytic purposes. This section summarizes
various scenarios for merging/linking MEPS event files. 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 www.meps.ahrq.gov/data_stats/more_info_download_data_files.jsp.
Return To Table Of Contents
5.1 Linking to the Person-Level File
Merging characteristics of interest from person-level file
(e.g., MEPS 2005 Full Year Population Characteristics File, or MEPS 2005
Person-Level Use and Expenditure File) expands the scope of potential estimates.
For example, to estimate the total number of emergency room visits for persons
with specific demographic characteristics (e.g., age, race, sex, and education),
population characteristics from a person-level file need to be merged onto the
emergency room visit file. This procedure is illustrated below. The MEPS 2005
Appendix File, HC-094I, provides additional detail on how to merge MEPS data
files.
- Create data set PERSX by sorting the MEPS 2005 Full
Year Population Characteristics File by the person identifier, DUPERSID.
Keep only variables to be merged onto the emergency room visit file and DUPERSID.
- Create data set EROM by sorting the emergency room
visit file by person identifier, DUPERSID.
-
Create final data set NEWEROM by merging these two
files by DUPERSID, keeping only records on the emergency room visit file.
The following is an example of SAS code which completes these steps:
PROC SORT DATA=HCXXX (KEEP= DUPERSID AGE31X AGE42X
AGE53X
SEX RACEX EDUCYR) OUT=PERSX;
BY DUPERSID;
RUN;
PROC SORT DATA=EROM;
BY DUPERSID;
RUN;
DATA NEWEROM;
MERGE EROM (IN=A) PERSX(IN=B);
BY DUPERSID;
IF A;
RUN;
Return To Table Of Contents
5.2 Linking to the Prescribed Medicines File
The RXLK file provides a link from the MEPS event files to
the Prescribed Medicine Event File. When using RXLK, data users/analysts should
keep in mind that one inpatient stay can link to more than one prescribed
medicine record. Conversely, a prescribed medicine event may link to more than
one inpatient stay visit or different types of events. When this occurs, it is
up to the data user/analyst to determine how the prescribed medicine
expenditures should be allocated among those medical events. For detailed
linking examples, including SAS code, data users/analysts should refer to the
MEPS 2005 Appendix File, HC-094I.
Return To Table Of Contents
5.3 Linking to the Medical Conditions File
The CLNK provides a link from MEPS event files to the 2005
Medical Conditions File. When using the CLNK, data users/analysts should keep in
mind that (1) conditions are self-reported, (2) there may be multiple conditions
associated with an emergency room visit and (3) a condition may link to more
than one emergency room visit or any other type of visit. Data users/analysts
should also note that not all emergency room visits link to the medical
conditions file.
Return To Table Of Contents
5.4 Pooling Annual Files
To facilitate analysis of subpopulations and/or low
prevalence events, it may be desirable to pool together more than one year of
data to yield sample sizes large enough to generate reliable estimates.
For more details on pooling MEPS data files see www.meps.ahrq.gov/data_stats/download_data_files_detail.jsp?cboPufNumber=HC-036.
Starting in Panel 9, values for DUPERSID from previous
panels will occasionally be re-used. Therefore, it is necessary to use the panel
variable (PANEL) in combination with DUPERSID to ensure unique person-level
identifiers across panels. Creating unique records in this manner is advised
when pooling MEPS data across multiple annual files that have one or more
identical values for DUPERSID.
Return To Table Of Contents
5.5 Longitudinal Analysis
MEPS Panel Longitudinal Weight files containing estimation
variables to facilitate longitudinal analysis are available for downloading in
the data section of the MEPS Web site.
Return To Table Of Contents
References
Cohen, S.B. (1998). Sample Design of the 1996 Medical
Expenditure Panel Survey Medical Provider Component. Journal of Economic
Social Measurement. Vol. 24, 25-53.
Cohen, S.B. (1997). Sample Design of the 1996 Medical
Expenditure Panel Survey Household Component. Rockville (MD): Agency for Health
Care Policy and Research; 1997. MEPS Methodology Report, No. 2. AHCPR Pub. No. 97-0027.
Cohen, J.W. (1997). Design and Methods of the Medical
Expenditure Panel Survey Household Component. Rockville (MD): Agency for Health
Care Policy and Research; 1997. MEPS Methodology Report, No. 1. AHCPR Pub. No. 97-0026.
Cohen, S.B. (1996). The Redesign of the Medical
Expenditure Panel Survey: A Component of the DHHS Survey Integration Plan. Proceedings of the COPAFS Seminar on Statistical
Methodology in the Public Service.
Cox, B.G. and Cohen, S.B. (1985). Chapter 6: A Comparison
of Household and Provider Reports of Medical Conditions. In Methodological
Issues for Health Care Surveys. Marcel Dekker, New York.
Cox, B. and Iachan, R. (1987). A Comparison of Household
and Provider Reports of Medical Conditions. Journal of Economic and Social
Measurement. 82(400):1013-18.
Edwards, W.S., Winn, D.M., Kurlantzick V., et al. (1994).
Evaluation of National Health Interview Survey Diagnostic Reporting. National
Center for Health Statistics, Vital Health 2(120).
Elixhauser A., Steiner C.A., Whittington C.A., and
McCarthy E. Clinical Classifications for Health Policy Research: Hospital
Inpatient Statistics, 1995. Healthcare Cost and Utilization Project, HCUP-3
Research Note. Rockville, MD: Agency for Health Care Policy and Research; 1998.
AHCPR Pub. No. 98-0049.
Health Care Financing Administration (1980). International
Classification of Diseases, 9th Revision, Clinical Modification (ICD-CM).
Vol. 1. (DHHS Pub. No. (PHS) 80-1260). DHHS: U.S. Public Health Services.
Johnson, A.E. and Sanchez, M.E. (1993). Household and
Medical Provider Reports on Medical Conditions: National Medical Expenditure
Survey, 1987. Journal of Economic and Social Measurement. Vol. 19,
199-233.
Monheit, A.C., Wilson, R., and Arnett, III, R.H.
(Editors). Informing American Health Care Policy. (1999). Jossey-Bass Inc., San
Francisco.
Shah, B.V., Barnwell, B.G., Bieler, G.S., Boyle, K.E.,
Folsom, R.E., Lavange, L., Wheeless, S.C., and Williams, R. (1996). Technical
Manual: Statistical Methods and Algorithms Used in SUDAAN Release 7.0, Research Triangle Park, NC: Research Triangle Institute.
Return To Table Of Contents
D. Variable-Source Crosswalk
VARIABLE-SOURCE CROSSWALK
FOR MEPS HC-094E: 2005 EMERGENCY ROOM
VISITS
Survey Administration Variables
Variable |
Description |
Source |
DUID |
Dwelling unit ID |
Assigned in sampling |
PID |
Person number |
Assigned in sampling |
DUPERSID |
Person ID (DUID + PID) |
Assigned in sampling |
EVNTIDX |
Event ID |
Assigned in sampling |
EVENTRN |
Event round number |
CAPI derived |
ERHEVIDX |
Event ID for corresponding hospital stay |
Constructed |
FFEEIDX |
Flat fee ID |
CAPI derived |
PANEL |
Panel Number |
Constructed |
MPCDATA |
MPC data flag |
Constructed |
Return To Table Of Contents
Emergency Room Visit Event Variables
Variable |
Description |
Source |
ERDATEYR |
Event date – year |
CAPI derived |
ERDATEMM |
Event date – month |
CAPI derived |
ERDATEDD |
Event date – day |
CAPI derived |
SEEDOC |
Did p talk to MD this visit |
ER01 |
VSTCTGRY |
Best category for care p recv on vst dt |
ER02 |
VSTRELCN |
This vst related to spec condition |
ER03 |
LABTEST |
This visit did p have lab tests |
ER05 |
SONOGRAM |
This visit did p have sonogram or ultrsd |
ER05 |
XRAYS |
This visit did p have x–rays |
ER05 |
MAMMOG |
This visit did p have a mammogram |
ER05 |
MRI |
This visit did p have an MRI/Catscan |
ER05 |
EKG |
This visit did p have an EKG or ECG |
ER05 |
EEG |
This visit did p have an EEG |
ER05 |
RCVVAC |
This visit did p receive a vaccination |
ER05 |
ANESTH |
This visit did p receive anesthesia |
ER05 |
OTHSVCE |
This visit did p have oth diag tests/exams |
ER05 |
SURGPROC |
Was surg proc performed on p this visit |
ER06 |
MEDPRESC |
Any medicine prescribed for p this visit |
ER08 |
VAPLACE |
VA facility flag |
Constructed |
ERICD1X |
3-digit ICD-9-CM condition code |
Edited |
ERICD2X |
3-digit ICD-9-CM condition code |
Edited |
ERICD3X |
3-digit ICD-9-CM condition code |
Edited |
ERPRO1X |
2-digit ICD-9-CM procedure code |
Edited |
ERPRO2X |
2-digit ICD-9-CM procedure code |
Edited |
ERCCC1X |
Modified Clinical Classification Code |
Constructed/Edited |
ERCCC2X |
Modified Clinical Classification Code |
Constructed/Edited |
ERCCC3X |
Modified Clinical Classification Code |
Constructed/Edited |
Return To Table Of Contents
Flat Fee Variables
Variable |
Description |
Source |
FFERTYPE |
Flat fee bundle |
Constructed |
FFBEF05 |
Total # of visits in FF before 2005 |
FF05 |
FFTOT06 |
Total # of visits in FF after 2005 |
FF10 |
Return To Table Of Contents Imputed Total Expenditure Variables
Variable |
Description |
Source |
ERXP05X |
Total exp for event (ERFXP05X + ERDXP05X) |
Constructed |
ERTC05X |
Total chg for event (ERFTC05X + ERDTC05X) |
Constructed |
Return To Table Of Contents
Imputed Facility Expenditure Variables
Variable |
Description |
Source |
ERFSF05X |
Facility amt pd, family (Imputed) |
CP Section (Edited) |
ERFMR05X |
Facility amt pd, Medicare (Imputed) |
CP Section (Edited) |
ERFMD05X |
Facility amt pd, Medicaid (Imputed) |
CP Section (Edited) |
ERFPV05X |
Facility amt pd, priv insur (Imputed) |
CP Section (Edited) |
ERFVA05X |
Facility amt pd, Veterans (Imputed) |
CP Section (Edited) |
ERFTR05X |
Facility amt pd, TRICARE/CHAMPVA (Imputed) |
CP Section (Edited) |
ERFOF05X |
Facility amt pd, oth federal (Imputed) |
CP Section (Edited) |
ERFSL05X |
Facility amt pd, state/local gov (Imputed) |
CP Section (Edited) |
ERFWC05X |
Facility amt pd, Workers Comp (Imputed) |
CP Section (Edited) |
ERFOR05X |
Facility amt pd, oth priv (Imputed) |
Constructed |
ERFOU05X |
Facility amt pd, oth pub (Imputed) |
Constructed |
ERFOT05X |
Facility amt pd, oth insur (Imputed) |
CP Section (Edited) |
ERFXP05X |
Facility sum payments ERFSF05X – ERFOT05X |
Constructed |
ERFTC05X |
Total facility charge (Imputed) |
CP Section (Edited) |
Return To Table Of Contents
Imputed Physician Expenditure Variables
Variable |
Description |
Source |
ERDSF05X |
Doctor amount paid, family (Imputed) |
Constructed |
ERDMR05X |
Doctor amount pd, Medicare (Imputed) |
Constructed |
ERDMD05X |
Doctor amount paid, Medicaid (Imputed) |
Constructed |
ERDPV05X |
Doctor amt pd, priv insur (Imputed) |
Constructed |
ERDVA05X |
Doctor amount paid, Veterans (Imputed) |
Constructed |
ERDTR05X |
Doctor amount pd, TRICARE/CHAMPVA (Imputed) |
Constructed |
ERDOF05X |
Doctor amt paid, oth federal (Imputed) |
Constructed |
ERDSL05X |
Doctor amt pd, state/local gov (Imputed) |
Constructed |
ERDWC05X |
Doctor amount pd, Workers Comp (Imputed) |
Constructed |
ERDOR05X |
Doctor amt pd, oth private (Imputed) |
Constructed |
ERDOU05X |
Doctor amt pd, oth pub (Imputed) |
Constructed |
ERDOT05X |
Doctor amt pd, oth insur (Imputed) |
Constructed |
ERDXP05X |
Doctor sum payments ERDSF05X – ERDOT05X |
Constructed |
ERDTC05X |
Total doctor charge (Imputed) |
Constructed |
IMPFLAG |
Imputation status |
Constructed |
Return To Table Of Contents
Weights
Variable |
Description |
Source |
PERWT05F |
Expenditure file person weight, 2005 |
Constructed |
VARSTR |
Variance estimation stratum, 2005 |
Constructed |
VARPSU |
Variance estimation PSU, 2005 |
Constructed |
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