Medicare Current Beneficiary Survey (MCBS)
Appendix B, National Healthcare Quality Report, 2008
The Medicare Current Beneficiary Survey (MCBS) is conducted by the Office of Strategic Planning of the Centers for Medicare & Medicaid Services (CMS). It is a continuous, multipurpose survey of a nationally representative sample of the Medicare population, providing information on aged and disabled Medicare beneficiaries living in communities and long-term care facilities. The sample is selected from Medicare enrollment files, and sample persons are interviewed three times per year over a 4-year period. Sample data are collected through computer-assisted personal interviews of the beneficiary or a proxy respondent if the sample person is not available for the interview. Survey questionnaires are tailored to the residence of the sample person—community or long-term care facility. If the sample person moves from one setting to the other during the period covered by an interview, a separate interview is administered for the time spent in each setting. Thus, beneficiaries are followed continuously over time regardless of where they live.
The primary goal of the survey is to collect comprehensive information on all medical services used by Medicare beneficiaries, sources of payment, health insurance coverage, and socioeconomic and demographic characteristics of the population. These data are used by the Office of Strategic Planning and the Office of the Actuary to support a host of activities related to the administration of the Medicare program (health insurance for older and disabled people) and the Medicaid program (Federal grants to States for medical assistance programs). CMS also uses the data to evaluate the Medicare and Medicaid programs and to assess the financial impact of programmatic change on beneficiaries and the Medicare trust fund.
Two public use files (PUFs) are created for each calendar year of data collected in the MCBS: Access to Care (AC) and Cost and Use (CU). The Access to Care PUFs provide "snapshot" estimates of the characteristics of the Medicare population who were enrolled on January 1 and were still alive and eligible for the survey in the fall of each year. They contain information on access to and satisfaction with care, health status and functioning, and demographic and economic characteristics of the sample population. Access to Care PUFs also contain summarized utilization and program payment data from Medicare claims, but they do not include survey-reported information on health care use and expenditures. By omitting the survey-reported information, access to care files can be produced quicker than cost and use files, which contain complete information on the cost and use of health care services.
The Cost and Use file brings together survey information, which can only be obtained directly from a beneficiary with reliable information on services used, and Medicare payments made from administrative bill files. Survey-reported data include information on the use and cost of all types of medical services, as well as information on supplementary health insurance, living arrangements, income, health status, and physical functioning. The survey also collects information on health services not covered by Medicare, most notably, prescription drugs and long-term facility care. Medicare bill data include use and cost information on inpatient hospitalizations, outpatient hospital care, physician services, home health care, durable medical equipment, skilled nursing home services, hospice care, and other medical services. This combination file can support a much broader range of research and policy analyses on the Medicare population than would be possible using either survey data or administrative bill data alone.
The 2004 Cost and Use file has undergone a careful reconciliation process to identify separately health care services reported from both sources, from the bill alone, and from the survey alone. This process has produced a file with a more complete and accurate picture of health services received, amounts paid, and sources of payment.
MCBS Table Notes
Tables Used in the 2008 NHDR
The 2008 NHDR includes four MCBS tables using the 2004 Cost and Use file and one using the 2005 Access to Care file. All tables include full-year community residents age 65 and over (H_AGE ≥65 and TYPE = "C"), excluding persons with missing values.
|Measure title||MCBS file||Source variable|
|Medicare beneficiaries age 65 and over who had an eye examination in the last 12 months||CU 2004||EDOCEXAM|
|Female Medicare beneficiaries age 65 and over who had a mammogram in the last 12 months||CU 2004||MAMMOGRM|
|Medicare beneficiaries age 65 and over who had an influenza vaccination in the last winter (September-December)||CU 2004||FLUSHOT|
|Medicare beneficiaries age 65 and over who received dental care in the last 12 months||CU 2004||DUAEVNTS|
|Medicare beneficiaries age 65 and over with delayed care due to cost||AC 2004||HCDELAY|
MCBS Sample for NHDR
The sample size and weighted sample size used to generate statistics for the NHDR are given in the following table. Because the denominator excludes records with missing values, the sample size varies slightly among tables.
|Sample size||Weighted size||Sample size||Weighted size|
|85 and older||1,488||3,923,794||1,971||3,790,385|
Because both AC and CU files contain the demographic variables, and the AC files have a much larger sample size, CU files are not merged to the AC files.
MCBS tables are created with column headings for race, ethnicity, and poverty status. The MCBS race and ethnicity variables are coded from beneficiary responses to the survey questions, and the categories are recorded as interpreted by the respondent. The race variable D-RACE in CU files includes American Indian, Asian or Pacific Islander, Black or African American, White, more than one race, and other categories. In the CU tables, "more than one race" and "other" categories are combined. The race variable in the AC file (D_RACE2) has different categories (Asian, African American, Native Hawaiian or Pacific Islander, White, American Indian or Alaska Native, more than one race, and other categories). More than one race and other categories are not reported in the AC table.
Ethnicity categories in the tables include total non-Hispanic, all races; non-Hispanic White; non-Hispanic Black; and Hispanic, all races. The variable is coded based on source variable D_ETHNIC and D_RACE or D_RACE2. Hispanics include persons of Mexican, Puerto Rican, Cuban, Central or South American, or other Spanish culture or origin, regardless of race.
Poverty status categories are slightly different between CU and AC tables. For the tables using the CU files, it is created based on reported or imputed income from all sources in dollars (INCOME_C). Each person is assigned to a poverty status category by using U.S. Bureau of the Census data on poverty thresholds for 2002, by size of family and number of related children under age 18. The constructed variables are based on the assumption that unmarried beneficiaries are one-person families and married beneficiaries are two-person families.
AC files only have a category variable INCOME and poverty status is based on the category variable only; size of family and number of related children are not considered. The categories are defined as: Negative or poor: income $0-$10,000; Near poor or low income: $10,001-$20,000; Middle income: $20,001-$40,000; and High income: more than $40,000. The "Near poor/low" category included 775 records with "-25" value, e.g. less than $25,000; and the "Middle" category included 361 records with value of "25," more than $25,000.
Age—Three age categories are developed for the NHDR tables on older community residents: 65 to 74, 75 to 84, and 85 and over.
Gender—Gender is recorded as reported on the Medicare/Social Security administrative record for the sample person.
Insurance coverage—Insurance coverage in the MCBS is based on a combination of Medicare and Medicaid administrative data and survey-reported information on public and private insurance.
The types of insurance identified in the MCBS include Medicare fee-for-service, Medicare managed care, Medicaid, private employer-sponsored, private individually purchased (Medigap), private health maintenance organization (HMO), and other insurance. Summary versions of these variables are used to create four mutually exclusive groups of Medicare beneficiaries by prioritizing insurance coverage as follows:
- Group 1 contains everyone who had Medicaid regardless of other coverage.
- Group 2 contains persons in Medicare managed care plans regardless of other coverage.
- Group 3 contains persons with private insurance (Medigap, employer-sponsored, or HMO).
- Group 4 contains all remaining beneficiaries (i.e., Medicare fee-for-service beneficiaries who did not have Medicaid or private insurance).
Residence location—Sample persons are classified as living in a metropolitan or nonmetropolitan area based on their addresses in the Medicare administrative files.
Perceived health status—Each sample person in the MCBS is asked to compare his or her general health to other persons of the same age. Persons receiving a community interview answer the question themselves. If a sample person is not able to do so, the proxy for that person answers the question. The possible responses to the question include excellent, very good, good, fair, and poor.
Functional limitations—Sample persons are identified as having functional limitations through their responses to six sets of questions about activities of daily living (ADLs) and instrumental activities of daily living (IADLs). Sample persons are asked whether they have a health or physical problem that makes it difficult to perform any of the specified activities. If the response is yes, they are recorded as having a limitation in that particular activity. If the response is "doesn't do," they are asked whether it is because of a health or physical problem. Then, if the response to the followup question is "yes," they are recorded as having a limitation in that particular activity.
The ADLs are activities related to personal care; they include bathing or showering, dressing, eating, getting in or out of bed or a chair, walking, and toileting. The IADLs are activities related to independent living; they include using the telephone, doing light housework, doing heavy housework, preparing meals, shopping for personal items, and managing money. Any limitation reported by a sample person may have been temporary or chronic at the time of the interview.
Computation of Statistics and Standard Errors
The percentages in the tables are weighted, and standard errors are included in the tables in order to assess the impact of sampling variability on the accuracy of the estimates. They were estimated by using a software package (SUDAAN) that accounts for the impact of non-random sampling procedures on the precision of the weighted estimates.
If a cell has fewer than 30 observations or the relative standard error of the estimate is greater than 0.30, the value for that cell is suppressed. This rule is implemented to avoid reporting statistically unreliable estimates of the characteristics of older community residents.
Return to Appendix B: Detailed Methods