MEPS Insurance Component: Technical Notes and Survey Documentation
I. Overview
The MEPS-IC is an annual survey of establishments that collects
information about employer-sponsored health insurance offerings
in the United States.
The MEPS-IC sample of employers is actually two different
samples:
- The List Sample, a nationally representative
sample of employers developed from Census Bureau list frames.
-
The Household Link Sample, a sample of employers of persons
who respond to the MEPS Household Component (MEPS-HC) survey. (Collection of the Household Link Sample was suspended in 2002.)
Although these two samples are from different sources and
the data are collected for different analytical purposes,
the questions asked of the respondents are identical. Thus,
to save costs and reduce respondent burden by having a single
data collection, editing, and imputation process, these two
survey collections have been integrated into a single data
collection effort. All of the tables posted on the MEPS-IC
Web site are derived from the List Sample.
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II. State
Estimates
In addition
to producing national estimates, the sample allocation
and design of the IC list sample also supports reliable
State-level
estimates of the following:
- Establishment
characteristics (for example, the percent of establishments that offer health
insurance)
-
Employee characteristics (for example, the percent of employees that enroll in
health insurance plans)
-
Premiums and employee
contributions for those enrolled in employer-sponsored health insurance plans
Survey cost constraints initially prevented the
fielding of a sufficiently large sample to support State estimates for all 50
States and the District of Columbia every year. (For survey purposes, the
District of Columbia is treated as a State.) In 1996, estimates were made for
the 40 most populous States. From 1997 through 2002, the MEPS-IC rotated
the
samples in the 20 least populated States to insure that every State received
an adequate sample size to make State-level estimates at least once every
four
years. Since 2003, there has been a sufficient MEPS-IC sample to support
State-level estimates in all 50 States and the District of Columbia.
The 21 States that were not allocated
sufficient sample for estimates each year during the years 1996 - 2002 are
listed in the table on the following page. An "X" indicates the year(s)
for which State estimates are available for that State. A blank indicates that
estimates are not available for that State in that year. The State rotation
schedule was modified in 2001 to reflect changes in State population rankings
based on the 2000 Census.
Federal agencies, State governments, and
non-profit organizations have occasionally provided additional funding to
increase the MEPS-IC samples in selected States. The two most common reasons for
funding larger State samples are 1) to improve the accuracy of the State
estimates for that year or 2) to provide sufficient sample for production of
State estimates in a year where no estimates would have been produced otherwise.
In the table below, States that received increased samples are listed by year.
In 2001 and 2002, the increased samples resulted in additional States for which
estimates could be produced. These additional estimates are provided on the MEPS-IC Web site to all data users.
Year
|
States with additional sample purchases
|
1998 |
Arizona, Massachusetts, Washington |
2000
|
Arkansas, Wisconsin |
2001
|
Delaware*, Vermont*, Kansas**, New Hampshire**,
South Dakota**, Wisconsin |
2002 |
Hawaii*, Maine*, Montana*, Maryland, Virgin Islands*** |
2003 |
Virginia |
|
* |
States received an additional sample that
supported a full set of State estimates not otherwise possible. |
** |
States received an additional sample that
supported estimates for smaller firms only. |
*** |
The U.S. Virgin Islands received a special
sample to support a full set of estimates. These data are not included
in the calculation of totals for the United States. |
States with smaller
populations for which MEPS-IC estimates are not available each year
1996–2002
Note:
An X
indicates that State-level estimates are available for that year; a blank
indicates that there are no estimates for that year. |
State |
1996 |
1997 |
1998 |
1999 |
2000 |
2001 |
2002 |
Alaska |
|
X |
|
|
|
X |
|
Arkansas |
X |
X |
X |
X |
X |
X |
|
Delaware |
|
|
X |
|
|
X* |
X |
District of Columbia |
|
X |
|
|
|
X |
|
Hawaii |
X |
X |
|
X |
|
X |
X* |
Idaho |
|
|
X |
|
|
X |
|
Kansas |
X |
X |
X |
X |
X |
** |
X |
Maine |
X |
X |
|
X |
|
X |
X* |
Mississippi |
X |
X |
|
X |
X |
X |
X |
Montana |
|
|
|
X |
|
|
X* |
Nebraska |
X |
|
X |
X |
X |
|
X |
Nevada |
X |
X |
|
X |
|
X |
X |
New Hampshire |
|
|
X |
|
X |
** |
X |
New Mexico |
X |
|
X |
|
X |
|
X |
North Dakota |
|
|
|
|
X |
|
|
Rhode Island |
|
X |
|
X |
|
X |
|
South Dakota |
|
|
|
|
X |
** |
|
Utah |
X |
X |
X |
|
X |
X |
X |
Vermont |
|
|
|
X |
|
X* |
|
West Virginia |
X |
|
X |
|
X |
|
X |
Wyoming |
|
|
X |
|
|
|
X |
* States received an additional
sample that supported a full set of State estimates not otherwise
possible.
** States received an additional sample that supported estimates for
smaller firms only. |
^top
III. Metro Area Estimates
Starting with
the 2002 data collection, the sample allocation and design of
the MEPS-IC list sample also supports a limited set of reliable
metro-level estimates of the following:
- The
percent of establishments that offer health insurance
- The
percent of employees that enroll in health insurance plans, are
eligible to enroll, and enroll when they are eligible
- Average premiums and employee contributions
for those enrolled in employer-sponsored health insurance plans
Estimates are provided for the 20 largest metro areas nationwide
and for at least one metro area within each state. The metropolitan
statistical areas with a sufficient sample size to support reliable
estimates with the MEPS-IC are geographically defined in the following
two tables:
^top
IV. Data Collection Process
For all sample units except State governments and
very large local governments, each sample unit is initially prescreened by
telephone. The purpose of this screening is to:
- obtain the name and title of an appropriate
person in each establishment to whom a MEPS-IC questionnaire will be mailed,
- verify the address and identify any businesses
that no longer exist, have closed, or have merged with others, and
- determine whether or not health insurance was
offered to employees at this establishment during the prior calendar
year. (The MEPS-IC survey is a retrospective survey, asking about health
insurance offerings during the previous calendar year. This is necessary in
order to collect data for both the list sample and the household link sample
cases at the same time. Beginning in 2008, the MEPS-IC survey will change to a collection of data for the current year.)
If the employer did not offer health
insurance in the previous year, a brief set of questions about establishment
characteristics are asked and the case is considered a complete respondent. This
provides a quick and inexpensive method to collect the necessary data from the
large number of employers who did not offer health insurance to their employees.
If the employer did offer health insurance
in the previous year, several brief questions are asked and the employer is
mailed a MEPS-IC questionnaire. All establishments not reached during the
screening process are also mailed questionnaires. If an establishment fails to
return the initial mail questionnaire, a follow-up mailing is sent a few weeks
later. Establishments that also fail to respond to the second mailing are
contacted by telephone and the survey is conducted using computer-assisted
telephone interviewing (CAPI) technology.
For the purpose of this survey, establishments
indicating that they offered health insurance to their employees must answer key
information on their health insurance offerings to be considered full
respondents. Callbacks are made to respondents not providing all of the key
information in order to complete their questionnaires. Respondents that do not
provide this key information, but are known to offer insurance, are considered
partial respondents. Establishments that were not prescreened, did not return
the mail questionnaires and did not respond to follow-up phone calls are
classified as non-respondents. For this group, the availability of health
insurance for employees at the establishment is unknown.
Data for large governments and large
private-sector firms, reporting for multiple establishments, are collected using
specialized staff and forms. This is done to make the collection process simple
and flexible and to reduce the burden as much as possible for these important
respondents. Sometimes multiple telephone contacts and personal visits are
needed to collect these data. For some of these collections, survey staff
abstract data directly from company records and plan brochures if the firm
insists on such methods.
^top
V. Estimation
In sample surveys like the
MEPS-IC, non-certainty sample establishments represent not only themselves
but also other similar
establishments in the survey population. Therefore, in order to produce
the survey estimates and standard errors presented in the MEPS-IC tables,
weights must be created for all responding establishments. A brief
description of this process is provided here.
During the sample design and selection process,
each establishment on the frame is given a probability of selection that
is
dependent on its stratum. These probabilities vary among establishments
and assure that the sample sizes in each stratum are equal to that required by
the allocation scheme. The inverse of this probability of selection is the
establishment’s base weight. The use of the base weight and the formula
provides an unbiased estimate of a total T, if
there is no non-response.
Because there is non-response, respondents’
weights are adjusted to account for non-response so that these weights, when
used with responding establishment data, will reduce the bias attributable to
survey non-response. To accomplish this, the sample is divided into cells
similar to the original sampling strata and the weights for each respondent in a
specific cell are adjusted upward by the same percentage. The sum of the
adjusted weights for respondents in these cells is equal to the sum of the base
weights for all in-scope sampled establishments in the cell. Because it is
assumed that the expected value of all responding establishments in each
individual cell defined is equal to that of all the eligible respondents, use of
the adjusted weights with respondents should produce the desired unbiased
estimates of totals. Additional details on the enrollment and expenditure
estimation process are available in MEPS
Methodology Report No. 14, June 2003.
After adjustment for non-response, weights are
post-stratified (Madow, Olkin, and Rubin, 1983.) using the frame of
establishments in business during the last quarter of the year for which
estimates would be made to produce control totals. For detailed
information concerning construction of weights, see MEPS Methodology
Report No. 8, November 1999.
Although railroads are included in the sample,
the 13 largest railroads are not included in the MEPS-IC tables.
Employment for these railroads can not be broken down by State so their
inclusion would distort results for States in which the headquarters of these
railroads are located.
» Reliability of Estimates
For each table of estimates, a corresponding
table of standard errors is provided. Standard errors are produced using
the method of random groups. (Skinner, Holt and Smith, 1989.) The
method is as follows:
- During the sequential sample selection process, each
establishment selected is assigned a number corresponding to its place in the
order of selection. These selection numbers are converted to 10 groups
numbered 0 to 9 by assigning an establishment to the group determined by the
last digit in its selection number. Thus, if the selection number were 73,
the establishment would be assigned to group 3. Each group can then be
thought of as a subsample similar to the full sample with each unit with a
chance of selection into the subsample that was one-tenth its chance of
selection into the full sample.
-
Using subsample weights that are 10 times the
nonresponse adjusted weights of the full sample, ten subsample estimates, Ei
, i = 1, ...10 are made in addition to the full sample estimate, E.
-
The standard
error is calculated as:
^top
VI. Table Numbering System
The MEPS-IC tables are numbered in a hierarchical
structure that facilitates locating estimates, helps clarify specifically what
the estimates are measuring, and provides a mechanism for calculating count
estimates for tables where percentages are provided. The numbering
structure also serves as the framework for the MEPSnet/IC interactive search
tool.
The first level of the table numbering system
is by the following categories and by year:
|
I. |
|
Private-sector data by firm size and selected characteristics |
|
II. |
|
Private-sector data by firm size and State |
|
III. |
|
Public-sector data by government type, government size, and census division |
|
IV. |
|
National totals for enrollees and cost of health insurance coverage for
the private and public sectors |
|
V. |
|
Private-sector data by industry groupings and State |
|
VI. |
|
Private-sector data by ownership type and age of
firm and State |
|
VII. |
|
Private-sector data by proportion of employees who
are full-time or low-wage and State |
|
VIII. |
|
Private-sector data by average wage quartiles and State |
|
IX. |
|
Private-sector data by Metro areas |
Within each of these categories (excluding Tables IV and IX), tables are
subsequently grouped by:
|
A.
|
Establishment-level tables |
|
B.
|
Employee-level tables |
|
C.
|
Premiums, employee contributions, and enrollment
tables for single coverage plans |
|
D.
|
Premiums, employee contributions, and
enrollment tables for family coverage plans |
|
E.
|
Premiums, employee contributions, and enrollment tables for employee-plus-one
coverage plans |
|
F.
|
Deductible, copayment, and coinsurance tables |
Tables within each of these categories are
ordered based on their inter-relationships.
To clarify what each MEPS-IC table is measuring,
it will be helpful to use the table (Table 1)
below. For
each of the MEPS-IC tables (excluding Tables IV and IX), Table
1 identifies the denominator table of that table.
Examples of how to use this table to calculate
approximate counts from the percentage estimates in the MEPS-IC tables
are provided in the next section.
Table 1. Listing of MEPS-IC table numbers
and denominators for tables
Table no.
|
Denominator
for table |
|
Table no.
|
Denominator for table |
A.1. |
|
|
|
A.1.a. |
A.1. |
C.1. |
|
A.2. |
A.1. |
C.1.a. |
|
A.2.a. |
A.2. |
C.1.b. |
|
A.2.b. |
A.2. |
C.1.c. |
|
A.2.b.(1). |
A.2. |
C.2. |
|
A.2.b.(2). |
A.2. |
C.2.a. |
|
A.2.b.(3). |
A.2. |
C.2.b. |
|
A.2.c. |
A.2. |
C.2.c. |
|
A.2.c.(1). |
A.2. |
C.3. |
C.1. |
A.2.c.(2). |
A.2. |
C.3.a. |
C.1.a. |
A.2.c.(3). |
A.2. |
C.3.b. |
C.1.b. |
A.2.d. |
A.2. |
C.3.c. |
C.1.c. |
A.2.e. |
A.2. |
C.4. |
B.2.b. |
A.2.f. |
A.2 |
C.4.a. |
C.4. |
A.2.g. |
|
|
|
|
|
|
|
B.1. |
|
D.1. |
|
B.1.a. |
B.1. |
D.1.a. |
|
B.2. |
B.1. |
D.1.b. |
|
B.2.a. |
B.2. |
D.1.c. |
|
B.2.a.(1). |
B.2.a. |
D.2. |
|
B.2.b. |
B.2. |
D.2.a. |
|
|
B.2.b. |
D.2.b. |
|
B.2.c. |
B.2. |
D.2.c. |
|
B.3. |
|
D.3. |
D.1. |
B.3.a. |
B.3. |
D.3.a. |
D.1.a. |
B.3.b. |
B.3. |
D.3.b. |
D.1.b. |
B.3.b.(1). |
B.3.b. |
D.3.c. |
D.1.c. |
B.3.b.(1).(a). |
B.3.b.(1). |
D.4. |
B.2.b. |
B.3.b.(2). |
B.3.b. |
D.4.a. |
D.4. |
B.4. |
|
|
|
B.4.a. |
B.4. |
E.1.
|
|
B.4.b. |
B.4. |
E.2.
|
|
B.4.b.(1). |
B.4.b. |
E.3.
|
E.1.
|
B.4.b.(1).(a). |
B.4.b.(1). |
E.4.
|
B.2.b.
|
B.4.b.(2). |
B.4.b. |
E.4.a. |
E.4. |
|
|
|
|
|
|
F.1 |
|
|
|
F.2 |
|
|
|
F.3 |
|
|
|
F.4 |
|
|
|
F.5 |
|
|
|
F.6
|
|
Note: Denominators are available only for tables that provide percentage estimates.^top
VII. How to Produce Count
Estimates from Percents
Many of the MEPS-IC tables contain percent
estimates instead of count estimates. For instance, Table I.B.2 gives the
percent of employees who work in establishments that offer health insurance.
Table I.B.2.a gives the percent of employees who work at establishments
that
offer health insurance and who are eligible for health insurance. For most
tables of percents, a count of the number of employees or establishments in
any cell in the table can be calculated using data, for that cell, from the
current table and one or more tables containing the denominator(s) for that
cell.
To produce count estimates, one simply multiplies
the cell values from the selected table and all of the denominators for that
cell. For example, if one desired an estimate of total establishments that offer
health insurance, one can find the percentage of these establishments in Table
I.A.2 and determine from Table 1 on the previous page that Table I.A.1 contains
the value in the denominator of this percentage.
Thus, the estimated total number of
establishments that offer health insurance in 2002 is:
.572(percents must be converted to decimals)
x 6,138,063 = 3,510,972.
The first number (.572) is from Table I.A.2 and
the second (6,138,063) is from Table I.A.
An approximate standard error for this count
estimate can be computed using this formula:
where Est(1) and Est(2) are the estimates from
the two tables and Err(1) and Err(2) are the standard errors for those
estimates.
|
= 22,530 |
For some tables, a hierarchical structure exists
so more than two tables are needed to derive an approximate count. For example,
look at Table I.B.2.a, the percent of employees eligible for health
insurance. Table I.B.2 is listed as its denominator for Table I.B.2.a and Table
I.B.1 is the denominator for Table I.B.2. The values from all three tables,
I.B.1, I.B.2, and I.B.2.a must be used to derive an estimate of the count. Thus,
the estimated total number of employees eligible for health insurance in 2002
is
.771 x .883 x 111,437,203 = 75,865,668, with the three values coming from Tables
I.B.2.a, I.B.2, and I.B.1 respectively. Basically, one must multiply by a
series
of denominators until one reaches a table with numbers instead of percents (the
shaded areas of the Table 1 on the previous page). The standard error for
this
count estimate can be computed by using a logical expansion of the standard
error formula provided above.
^top
VIII. Major Changes to the MEPS-IC
Survey by Year
Each year the MEPS-IC survey undergoes a number of changes in an effort to
improve the existing survey while maintaining continuity from one year to the
next. Listed below are the most significant changes that occurred in each year.
In addition to the changes listed here, there were also changes to the wording
and question order based on feedback from survey respondents.
Survey year
|
Major
changes
|
|
1996
|
- Initial year of the survey.
|
1997
|
- Retiree health insurance questions were
dropped at the establishment-level and revised for collection at the
company-level.
- A rotation schedule to produce estimates for
smaller States was introduced.
- A significant expansion of the number of
tables was made, a new table-numbering system (previously described) was
introduced, and revised 1996 tables (using improved imputation and weighting
methods) were reissued. The 1996 tables posted on the MEPS-IC Web
site reflect these changes.
- Company-level forms (15 and 15 S) were added
for cases were data collection at the establishment-level was not feasible.
- The sample of Self Employed with No Employees
sample was dropped.
|
1998
|
- MEPSnet/IC – an interactive search mechanism
that produces trend output for all available years was introduced.
- Follow-up questionnaires (10M and 10MS) were
added for interviews of multi-establishment respondents where the Computer
Assisted Telephone Instrument was not functioning.
- The “first” plan-level questionnaire was
removed from the establishment and government questionnaires.
|
1999
|
- State-level estimates were expanded by
providing three new sets of tables with estimates by industry groupings,
ownership type, age of firm, and percent of full-time and low-wage employees.
- The government questionnaire was split into
front and rear parts – based on feedback from government respondents.
- Attempts to collect both current year data in
addition to retrospective data were dropped.
|
2000
|
- Retiree health insurance questions and
estimates were significantly expanded.
- The industry categories were changed to
conform to the change from SIC codes to NAICS codes. Comparisons
between 1999 and 2000 are not recommended.
- The definition of a low-wage employee was
changed so it would be automatically updated each year as wages increase or
decrease. Comparisons by low-wage employees between 1999 and 2000 are
not recommended.
|
2001
|
- Employee-plus-one premiums and employee
contributions were collected and new tables with these estimates were
produced.
- New State-level estimate tables by average
wage quartiles were produced.
|
2002
|
- Post-data collection processes were changed
to reduce the time it takes to post estimates on the MEPS Web site.
- Additional sample was added and separate
estimates were produced for the Virgin Islands.
|
2003 |
|
2004 |
- Questions on Health Savings Accounts (HSAs) and Health
Reimbursement Arrangements (HRAs) were added at the plan level.
|
2005 |
- HSA and HRA questions were significantly revised.
- Questions on prescription drug tiers and services covered by the plans were reduced in scope.
- Tables with estimates of average deductibles (single and family), and average copayments and coinsurances were added. Tables were created starting with year 2002.
|
2006 |
- Questions on employer deposits to HSA accounts were added.
|
2007 |
- No MEPS-IC data are available for 2007 due to the transition from retrospective to current data collection. Data for 2008 and beyond will be available a year earlier due to this change.
|
^top
IX.
References
Madow WG, Olkin I, Rubin DR. Incomplete data in sample
surveys, Volume 2: Theory and bibliographies. New York: Academic Press; 1983.
Skinner
CT, Holt D, Smith TMF. Analysis of complex surveys. New York: John Wiley
and Sons; 1989.
^top
Suggested
Citation:
MEPS Insurance Component: Technical Notes and Survey Documentation.
Agency for Healthcare Research and Quality, Rockville, Md. http://www.meps.ahrq.gov/survey_comp/ic_technical_notes.shtml
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