Medicare Frequently Asked Questions (FAQ)
Program | Data Processing | Data Files | Data Variables | Research Issues
- What is Medicare?
- What is a benefit period?
- What are lifetime reserve days?
- Who is eligible for Medicare?
- What is not covered by Medicare?
- Are prescriptions covered by Medicare?
- What is a claim?
- What is a final action claim?
- What are Carriers?
- Who processes Durable Medical Equipment (DME) claims?
- What are Fiscal Intermediaries (FIs)?
- What are Medicare Administrative Contractors (MACs)?
- What kind of data can I get from CMS?
- What types of files are there (categories)?
- What are some limitations of each category of files?
- What are the advantages of each category of files?
- What are the files contained under these categories (LDS and RIFs)?
- Why are people under age 65 in my Medicare dataset?
- How much do files cost?
- What factors influence the cost of files?
- Is there any reason I would need a Non-identifiable file if I already have a Limited Data Set (LDS) or Research Identifiable File (RIF)?
- What's the difference between Inpatient SAF and the MedPAR files?
- If I need to choose between MedPAR and the Inpatient SAF, which would you recommend?
- What is the difference between Carrier (Part B Physician/Supplier) data and Outpatient data?
- How are 5% samples selected?
- How can I find out what variables are in the RIFs?
- Can I identify attending and referring physicians for an inpatient stay?
- Can I use HCPCS for Inpatient, HHA, SNF, and Hospice files? I see those fields are listed in the record layout?
- What are Revenue Centers?
- What's a HIC?
- What's a BIC?
- Do HICs ever change?
- Why would I want to use Medicare data for my research?
- What are some of the limitations of Medicare data that I need to consider?
- How do I find articles that use Medicare data?
- How does the Privacy Act affect my access to and use of Medicare data?
- If I want outpatient data, what do I ask for?
- Why isn't the residence information (e.g. county code) found in the denominator file and claims files completely in agreement when I link them?
- How do I link Medicare data with my data?
- How do I link beneficiary or claim-level Medicare datasets?
- Will I be able to find all claims for an individual within a LDS file? Am I able to link beneficiaries across LDS files?
- For longitudinal or retrospective studies, what do I need to consider?
- How do I study a particular condition/disease?
- Can I figure out Medicare data without taking a training class?
Medicare is a Health Insurance Program for:
- People 65 years of age and older.
- Some people with disabilities under age 65.
- People with End-Stage Renal Disease (permanent kidney failure requiring dialysis or a transplant).
- People with Amyotrophic Lateral Sclerosis (ALS) -also known as Lou Gehrig's Disease
Medicare has four Parts:
- Part A (hospital insurance) - Most people do not have to pay for Part A.
- Part B (medical insurance) - Most people pay monthly for Part B.
- Part C (managed care) - this is optional, but beneficiaries must have both Parts A and B coverage to enroll.
- Part D (drug coverage) - new in 2007. Most people pay for Part D coverage.
For more information about Medicare Part A & B covered services, review the publication "Medicare & You".
Part A - Hospital Insurance (HI)
Part A helps beneficiaries pay for inpatient hospital care, care in critical access hospitals (small facilities that give limited outpatient and inpatient services to people in rural areas), short-term care in skilled nursing facilities, hospice care and some home health care.
Most people get Part A automatically when they turn age 65. They do not have to pay a monthly payment called a premium for Part A because they, or a spouse, paid Medicare taxes while they worked for 40 or more quarters in their lifetime. Persons age 65 and older that did not pay Medicare taxes while they worked may be able to buy Part A coverage.
Medicare beneficiaries are responsible for deductibles and co-insurance for Part A covered services:
Hospital Deductible: One deductible is charged per hospital admission ($1,024 in 2008). Hospital readmission within a 60-day period does not trigger another deductible.
Hospital Coinsurance: From the 61st day to the 90th day of hospitalization, beneficiaries are responsible for ¼ of the hospital deductible ($256 per day in 2008); from the 91st through the 150th day of hospitalization, the coinsurance equals ½ of the hospital deductible ($512 per day in 2008). The beneficiary is responsible for all hospital costs each day beyond 150 days. For more information on Medicare's payment policies for hospital stays, see MedPAC's summary titled Acute Inpatient Payment Basics. Long-term care hospital payment information can be found in MedPAC's Long-Term Care Hospitals Payment System document.
Skilled Nursing Facility (SNF) coinsurance: Day one through twenty is covered 100% by Medicare. The daily coinsurance for the twenty-first through one-hundredth day of SNF care is $128 per day in 2008. Medicare does not pay for SNF care beyond 100 days. For more information about Medicare SNF payments, see MedPAC's Skilled Nursing Facility Services Payment System.
Home Health Care: Beneficiaries who need skilled care on a part-time or intermittent basis and are largely confined to their homes are eligible for certain services at home under Medicare. Home health services are covered in 60-day units of care called episodes of care. Medicare pays for home health care services out of both Part A and Part B funds. No beneficiary copayment is required for these services. Other beneficiaries who are not confined to their homes may be eligible for Medicare-covered home care services under certain circumstances. For more information about Medicare's Home Health coverage, see Home Health Care Services Payment System from MedPAC.
Durable Medical Equipment: Beneficiaries are responsible for a 20% co-payment for durable medical equipment. For more information, see MedPAC's document, Durable Medical Equipment Payment System.
Hospice coinsurance: There is a copayment of up to $5 for outpatient prescription drugs and 5% of the Medicare-approved amount for inpatient respite care (not to exceed the inpatient Part A deductible amount of $1,024 in 2008). See MedPAC's Hospice Services Payment System for more information.
Inpatient Psychiatric Care: Medicare pays for up to 90 days of inpatient psychiatric care per episode of illness. The beneficiary is responsible for an inpatient deductible ($1,024 in 2008) and a per day copayment for days 61-90 of their stay ($256 per day in 2008). There is a lifetime coverage limit of 190 days. For more information, see MedPAC's Psychiatric Hospital Services Payment System.
Part B -Medical Insurance (SMI)
Part B covers Medicare-eligible physician, outpatient hospital and certain home health services; ambulance, lab and certain chiropractic services; durable medical equipment, bone mass measurements and screening mammograms. For 2008, the Part B deductible is $135.00 (the beneficiary also pays 20% of Medicare-approved service amounts after they meet the deductible). There is a monthly premium for Part B enrollment ($96.40 in 2008). A small percent of beneficiaries with higher incomes pay a higher monthly premium for Part B coverage.
Preventive Care Services that are not related to an underlying condition (such as diabetes) are generally not covered (i.e. routine physical exams, routine foot care, and most immunizations are not covered). Flu shots are covered.
Routine eye care, most eyeglasses and the cost of hearing aids are not covered. One pair of eyeglasses following cataract surgery is covered (the beneficiary pays the coinsurance and Part B deductible).
Cosmetic Surgery is generally not covered.
Complete coverage information can be found in the "Medicare and You" handbook.
Part D- Outpatient Drug Benefit
In January 2006, Medicare began offering a voluntary outpatient drug benefit known as “Part D”. The standard benefit for 2008 includes a $275 deductible, partial coverage (75%) of outpatient drug expenses from $276 - $2,510, no coverage (beneficiary pays 100% of drug costs) from $2,511 - $5,726, and an approximately 5% copayment (95% covered) for drug spending over $5,726.
Coverage for care in hospitals and skilled nursing facilities is measured in "benefit periods." In each benefit period, there are limits to the number of days Medicare will help pay for inpatient hospital, skilled nursing facility or hospice care. Once the limit is exceeded, the beneficiary is responsible for all charges for each additional day of care.
A benefit period begins the day of admission to a hospital. It ends when the beneficiary has been out of a hospital or skilled nursing facility for 60 straight days, including the day of discharge. A beneficiary must pay the inpatient hospital deductible for each benefit period. The benefit period also ends for those in a skilled nursing facility who have not received skilled nursing care for 60 straight days.
Once a benefit period has ended, a new benefit period begins and hospital and skilled nursing facility benefits are renewed. There is no limit to the total number of benefit periods.
60 non-renewable days that can be used over and above the 90 covered days of hospitalization during a benefit period. For instance, a beneficiary who stays in the hospital 95 days during a benefit period may elect to use 5 of his/her 60 lifetime reserve days, permanently reducing the total reserve days to 55.
From the Medicare web site
To be eligible for Medicare, one must be a U.S. citizen living in the U.S. or a foreign national who has applied for legal residency and has lived in the U.S. for a minimum of five years.
There are four categories of Medicare eligibility:
Social Security/Railroad Retiree:
Persons aged 65 or older who are eligible for Social Security or Railroad Retirement benefits. Medicare Part A is automatic and Part B is optional. Medicare Part A becomes available at age 65. For Medicare Part B enrollment can occur three months before, during the month of, and up to three months after a qualified individual's 65th birthday.
Social Security Disability/ESRD Recipients:
People under age 65 who meet the eligibility criteria for Social Security Disability can qualify for Medicare. However, individuals must first be entitled to Social Security benefits for 24 successive months in order to get Medicare. Thereafter, Medicare Part A is automatic and Part B is optional. In addition, individuals with End Stage Renal Disease (ESRD) are also eligible for Medicare.
Voluntary Enrollee:
Persons age 65 or older who are not qualified for Social Security can purchase Medicare coverage. A person who buys Medicare has the option of purchasing both Medicare Part A and Part B, or only Part B.
Although Medicare provides coverage for a wide range of acute care services, there are services that are not covered by Medicare. In addition, there are a number of cost-sharing requirements for Medicare beneficiaries. The gaps in coverage and cost-sharing amounts translate into direct out-of-pocket expenses for Medicare beneficiaries (hence, no claim records), unless they have supplemental insurance coverage, known as Medigap insurance.
PART A - Hospital Insurance
Hospital Deductible: One deductible is charged per hospital admission ($1,024 in 2008). Readmission within a 60-day period does not trigger another deductible.
Hospital Coinsurance: From the 61st day to the 90th day of hospitalization, beneficiaries are responsible for ¼ of the hospital deductible ($256 in 2008); from the 91st through the 150th day of hospitalization, coinsurance equals ½ of the hospital deductible ($512 in 2008).
Hospital Coverage Beyond 150 Days: Medicare does not pay for hospital coverage beyond 150 days.
Skilled Nursing Facility (SNF) coinsurance: Daily coinsurance for the twenty-first through one-hundredth day of SNF care ($128 per day in 2008).
SNF Care Beyond 100 Days: Medicare does not pay for SNF care beyond 100 days.
Home Health Care: Beneficiaries who need skilled care on a part-time or intermittent basis and are largely confined to their homes are eligible for certain services at home under Medicare. Home health services are covered in 60-day units of care called episodes of care. Medicare pays for home health care services out of both Part A and Part B funds. No beneficiary copayment is required for these services. Other beneficiaries who are not confined to their homes may be eligible for Medicare-covered home care services under certain circumstances.
Inpatient Psychiatric Care: Medicare does not pay for inpatient psychiatric care beyond 190 days.
Long-term Custodial Care: Medicare does not pay for nursing home care, adult day care or respite care.
Medical Care Outside the U.S.: Medicare does not pay for medical care outside of the U.S. except for certain limited services furnished in Canada and Mexico.
PART B - Medical Insurance
Preventive care services that are not related to an underlying condition (such as diabetes) are generally not covered (i.e. routine physical exams, routine foot care, and most immunizations are not covered). Flu shots are covered.
Routine eye care, most eyeglasses and the cost of hearing aids are not covered. One pair of eyeglasses following cataract surgery is covered (the beneficiary pays the coinsurance and Part B deductible).
Cosmetic surgery is generally not covered.
Complete coverage information can be found in "Medicare & You"
Medication given in a hospital/hospice/SNF setting are paid for by Medicare. However, the specific medicines that were dispensed are rarely coded or identifiable from the data files.
For outpatient prescription drug coverage information, read "Part D" under What is Medicare?
For information about chemotherapy in an outpatient setting, see Payments For Drug Administration Services in the Claims Processing Manual 100-04, Chapter 4.
A claim is a request for reimbursement that providers submit to insurance companies for services rendered. It includes the description of services and diagnoses.
Medicare Institutional claims: UB-04 (CMS-1450) form - replaces the UB-92 form
Medicare Non-Institutional claims: CMS-1500 form
A final action claim is a non-rejected claim for which a payment has been made. All disputes and adjustments have been resolved and details clarified.
Carriers handle (non-institutional) Part B claims. Doctors and other suppliers of medical services covered under Part B submit charges directly to a Medicare Carrier by "taking assignment". The doctor or supplier will receive the portion the bill paid by Medicare and will only bill the individual for the $135 deductible (2008), and if applicable, a 20% copayment. Free-standing ASCs that provide certain Medicare-approved procedures also submit their facility bills to the Carriers for payment under Part B.
CMS is in the process of replacing the Carriers with Medicare Administrative Contractors (MACs).
As of January 2006, DME claims are handled by four specialty Medicare Administrative Contractors (MAC). The following link has additional information about the DME MACs.
The Fiscal Intermediaries handled the adjudication of all institutional claims processed. Hospital charges for Medicare beneficiaries were billed by the hospital to the intermediary that pays them. CMS is in the process of replacing the FIs with Medicare Administrative Contractors (MACs).
CMS is in the process of replacing the FIs and Carriers with Medicare Administrative Contractors (MACs). These entities process claims from institutional and non-institutional providers. Full transition to MACs is scheduled for October 2009.
CMS is a medical insurance company. Therefore, the data available are claims and records of services that were paid for, and enrollment and eligibility information on the Medicare beneficiaries.
- Research Identifiable Files (RIFs)
- Limited Data Set Files (LDS)
- Non-identifiable Files
Research Identifiable Files (RIFs)
Research Identifiable Files (RIFs) contain person-specific data on Medicare providers, beneficiaries, and recipients including individual identifiers such as UPIN (Unique Physician Identification Number), name, or other elements that would permit the identity of a beneficiary or physician to be deduced (e.g., date of birth, age, race, sex, residence, ZIP code). Data with beneficiary or physician identifiers are subject to the Privacy Act, Freedom of Information Act and other Federal government rules and regulations. As such, the information is confidential and is to be used only for reasons compatible with the purpose(s) for which the data are collected. CMS employs strict security measures to safeguard individual privacy.
CMS data release policies seek to ensure that files containing physician and/or beneficiary identifiers are used only when necessary and in accordance with disclosure provisions of the Privacy Act. Researchers need to submit a data request packet to ResDAC and CMS for review. If CMS approves the data file release, researchers need to pay the costs incurred in the processing of data. This means the researchers need to have the significant resources to obtain these data files.
Limited Data Set Files (LDS)
CMS creates the LDS files by encrypting/blanking/ranging all identifiers from the associated RIFs. Both LDS and RIF files have the same record unit, same year available, same file updating schedule, and similar data structure (except for the encrypted or blanked variables). CMS requires that appropriate order form, signed Data Use Agreement (DUA), and fees be sent before releasing the LDS files. Compared with RIFs, LDS files are similar in price, but easier to obtain than RIFs.
LDS SAFs for Inpatient, Outpatient, HHA, SNF, and Hospice are available in three different versions: 5%, 100%, and State segments. For the LDS Carrier (Physician/Supplier Part B) files and the LDS DME SAFs, only 5% samples are available.
The 5% sample is created based on selecting records with 05, 20, 45, 70, or 95 in position 8 and 9 of the HIC number. Provider numbers are encrypted and beneficiary claim numbers in all files are replaced with a unique identifier to protect the privacy of individuals.
The Expanded Modified MedPAR files (also called the LDS MedPAR) contain records for 100% of Medicare beneficiaries who used hospital inpatient services or SNF services. The records are stripped (fields are not present) of most data elements that will permit identification of beneficiaries. The hospital is identified by the six digit Medicare provider number. Three Expanded Modified MedPAR files are available: MedPAR National, MedPAR State and MedPAR SNF.
The list of encrypted, blanked and ranged LDS variables can be found under What are some limitations of each category of files?
Additional LDS files information can be found on the CMS web site: Limited Data Sets
Non-identifiable Files
Non-identifiable Files are aggregated data that for most instances are not covered by the Privacy Act as there is no beneficiary- or physician-level data in these files. Some of the files are summaries of information found in the Research Identifiable Files and some contain information that cannot be derived from any other source.
To view the available Non-identifiable Files, go to the CMS web site: Non-identifiable Data Files
RIFs:
- Researchers must go through a rigorous process to obtain RIF data. See Requesting CMS RIF Data
LDS:
- Selected variables are encrypted, ranged or blanked: UPIN is encrypted, beneficiary age is ranged (by age groups), dates of service are by quarter and year, zip codes are blank (the lowest level of cross-sectional analysis is the county level for the SAFs and the state level for the MedPAR File). The LDS SAFs have a specific beneficiary key that allows the LDS SAFs to be linked; the LDS MedPAR file cannot be linked with any of the LDS SAFs.
Non-identifiable Files:
- No patient-or physician-specific data.
RIF:
- RIFs allow for beneficiary-specific analyses, including geographic analysis down to the zip code level.
LDS:
- LDS files are easier to obtain than RIFs. LDS file prices can be found directly on the CMS web site.
Non-identifiable File:
- Least expensive – some can be downloaded for free from the CMS web site
- Some Non-identifiable Files contain aggregate information that cannot be derived from LDS or RIF files
Denominator File
The Denominator File contains basic demographic, enrollment and eligibility information about each Medicare-enrolled beneficiary during a calendar year.
Standard Analytic Files (SAFs): Part A & Part B – Claims data
The Standard Analytical Files (SAFs) are generated by processing the National Claims History (NCH) file's raw claims through final action algorithms that match the original claim with adjusted claims to resolve any adjustments. SAFs are available for each institutional claim type (inpatient, outpatient, SNF, hospice, or HHA) and for Non-institutional files (Carrier, DME) beginning with 1991. The record unit of SAFs is the final action claim (some episodes of care may have more than one final action claim). Final action claim files are available to researchers approximately nine months into the following calendar year (for example: 2007 data will become available in September of 2008). The files are annual.
Stay Records File (MedPAR): Stay-level data
The Medicare Provider Analysis and Review (MedPAR) file contains inpatient hospital and SNF final action stay records. Each MedPAR record represents a stay in an inpatient hospital or SNF. A stay record summarizes all services rendered to a beneficiary from the time of admission to an inpatient facility through discharge. Each MedPAR record may represent one claim or multiple claims, depending on the length of a beneficiary's stay and the amount of inpatient services used throughout the stay. Since June 1995, the inpatient and SNF claims from the NCH file became the source for the MedPAR file. The record unit of MedPAR file is the hospital or SNF stay.
Annual MedPAR files, identified by the file update date, are available for fiscal years and calendar years 1991 forward. Inpatient stay records are contained in the MedPAR files by the beneficiary's discharge date. SNF stays are in the MedPAR files by SNF admission date.
There are other ways to become eligible for Medicare besides turning 65. See "Who are the Medicare beneficiaries?"
To determine the cost of the Non-identifiable Files and LDS files, go to Research, Statistics, Data & Systems on the CMS web site and look under Files for Order. If you are interested in obtaining a cost estimate for Research Identifiable data, please contact the ResDAC assistance desk. ResDAC will answer any questions you have about filling out your request for a formal CMS cost estimate and will submit the request to CMS on your behalf.
ResDAC can assist with determining the data files needed and the data extract methodology for the proposed research project.
- The number of finder files and method of their submission (i.e., submitted by requestor vs. developed by CMS)
- Number of sources of data desired
- Number of years of data desired
- Number of subjects in data file
All of these factors influence processing time which is directly related to cost.
Yes. Some files provide unique information not found in a LDS or RIF (e.g., Provider of Services file which contains facility-specific information) and others are summary files with limited variables that save work and are easier to work with.
You may also want to link a Non-identifiable File to your LDS or RIF claims. For instance, LDS and RIFs contain provider numbers only. If you linked RIF or LDS files with the Provider of Services Non-identifiable File, you would be able to see the facility names and addresses associated with the facility provider numbers. Also, you could link an ICD-9 file and have a description of each beneficiary's primary diagnosis.
The unit of analysis for the Inpatient SAFs is a claim and for the MedPAR it is a stay (an inpatient stay may have several claims).
The MedPAR file was specifically developed by CMS for researchers interested in studying inpatient hospital and skilled nursing facility (SNF) care. It creates a single, fixed-length record for each hospital or SNF stay. The file contains ICD-9 diagnosis and procedure codes, procedure dates and DRG. MedPAR does not contain HCPCS procedure codes. Information about charges for inpatient services are more highly aggregated in MedPAR than in the Inpatient SAF. Most researchers choose to use the MedPAR file when studying inpatient and SNF care.
The Inpatient SAF is an alternate source of information about services provided by long stay and short stay inpatient hospitals. The Inpatient SAF does not contain services provided by Skilled Nursing Facilities. Claims for services provided by Skilled Nursing Facilities are found in the Skilled Nursing Facility (SNF) Standard Analytic file.
The Inpatient SAF contains one record per bill (less than 1% of short stays have multiple bills), contains information about the attending physician (not available in MedPAR) and contains more detailed revenue center codes which record specific areas within a hospital involved in patient care (see "What are revenue centers?" ). However, SAFs are not as easily analyzed as the fixed-format MedPAR files and require more programming skill and manipulation.
With a few exceptions (see "If I want outpatient data, what do I ask for?"), the Carrier dataset contains claims filed on the CMS-1500 forms for services performed by physicians (non-institutional) and other health care providers (chiropractors, physician assistants, etc.) that have been sent to the Carriers for payment. The Outpatient file contains UB-04 (CMS-1450) claims sent by outpatient institutions to fiscal intermediaries for payment.
The 5% beneficiary sample is created based on selecting records with 05, 20, 45, 70, or 95 in position 8 and 9 of the Health Insurance Claim (HIC) number. See ResDAC's Technical Brief, Differences in How the Medicare 5% Files are Generated.
To learn about the variables in each of the RIFs, we recommend viewing the record layouts available on the ResDAC web site
Yes, they are recorded in the Inpatient SAF. However, the attending and referring physicians cannot be identified in the MedPAR files. ResDAC recommends using the Carrier file to study physician services.
We recommend that you don't. Per the CMS-1450 reporting procedures, HCPCS codes are not required for these claim types and as a result, are generally not reported. In cases where they are reported, they are not edited nor verified.
A revenue center is a revenue-producing division or unit within a hospital or other institution (e.g., emergency room, pathology).
In the Inpatient SAF, charges that accrue for a beneficiary's inpatient stay within each revenue center of the facility will be listed in aggregate by the code for the specific revenue center. The sum of the charges for each revenue center is listed in the Inpatient SAF; a listing of individual service charges that comprise that unit's total for each beneficiary is not identified. A list of revenue centers codes can be found in the Revenue Center Table.
In the MedPAR File, the revenue center charges for each inpatient stay are further aggregated into more generalized cost centers. The MedPAR file cost centers include: ICU (9 specific types), coronary care unit (6 specific types), pharmacy (separated by: general drugs and IV therapy, erythropoietin, blood clotting drugs, and combinations of the 3), transplant, radiology/oncology, diagnostic radiology, therapeutic radiology, CT scan, other radiological imaging, radiology nuclear medicine, outpatient care, organ acquisition, and ESRD.
An acronym for Health Insurance Claim number, a HIC is a unique identifier of a beneficiary. The HIC is also called the HICAN (High Can). The HIC usually consists of the nine-digit Social Security number (SSN) and two-character code (BIC) that stores the relationship between the beneficiary and the primary holder of the associated SSN. There are exceptions, though. For former railroad employees, the HIC could be a transformed version of their Railroad Board number, made to resemble an SSN. However, the first position is non-numeric, distinguishing it from an actual SSN.
Due to privacy concerns, CMS no longer releases HICs in their data files. An alternate identification number is generated by the CMS data vendors who create the data files for research use, and this beneficiary identification number does allow for linking of beneficiary claims across the various CMS claim files.
Short for the Beneficiary Identity Code, it is a two-digit alpha-numeric code that tells the relationship between the claimant and primary claimant (SSN). It also identifies the type of benefits the individual is receiving for statistical reports. For a list of BICs, go to the Denominator File record layout.
Yes. A few examples:
- A widow determines she could be drawing better benefits as a widow instead of based on her own work history. In order to do this, she needs to change her SSN to that of her late husband. This would result in her receiving a new HIC also.
- Someone has been fraudulently using a beneficiary's SSN. To protect themselves, the beneficiary has to change their SSN, and hence their HIC.
- A railroad employee had been drawing benefits based on their SSN, but realized their benefits would be better based on their designation as a former railroad employee. The HIC would then change to the railroad number, but the SSN would remain unchanged.
- Wage earner dies, the widow who remarries and draws benefits under her new husband would receive a new HIC.
- Most individuals who began drawing benefits through the Railroad Retirement Board prior to 1991 have all received new HICs from CMS resembling those drawing benefits via the Social Security Administration.
- Why would I want to use Medicare data for my research?
- Population-based
- Large sample sizes allow for the ability to detect rare events
- Not subject to recall bias
- Linkage of beneficiaries across years (for longitudinal/cohort studies) and datasets is possible
- The exclusion of persons under age 65 who are neither disabled nor have ESRD (End-Stage Renal Disease)
- The exclusion of individuals over 65 not enrolled in Medicare
- Exclusion of claims paid by a source other than fee-for-service Medicare (e.g., managed care organizations or HMOs)
- Data (variables) were collected for the purpose of making healthcare payments, not for research
To search for articles on your own we suggest using PubMed available from the National Library of Medicine. Consider using keywords such as 'Medicare', 'Medicare claims', and 'Medicare data'.
CMS data release policies seek to ensure that files containing physician and/or beneficiary identifiers are used only when necessary and in accordance with disclosure provisions of the Privacy Act. Researchers need to submit a data request packet to ResDAC and CMS for review. CMS will then approve or reject the data file release. The release of Limited Data Set Files (LDS) is also subject to a DUA despite the fact that physician and/or beneficiary identifiers are blanked out or encrypted. Any result that may lead to identification of an individual beneficiary (e.g. cell sizes less than 11) must be suppressed.
This depends on your definition of 'outpatient'. If you mean outpatient care provided in a hospital, the Outpatient SAF would meet your needs. However, if your definition of outpatient also includes 'ambulatory care', the answer is not as simple.
Free-standing Ambulatory Surgical Center (ASC) claims are found in the Carrier (Physician/Supplier Part B) SAF. ASCs are free-standing facilities or hospital-operated distinct entities that perform outpatient surgeries that generally take no more than 90 minutes and do not require an overnight stay. The most common procedures performed in ASCs are cataract removal with lens replacement, colonoscopy, other eye procedures, and some orthopaedic and gynecological procedures. By August 2007, more than 4,600 ASCs were approved to participate in the Medicare program, and approximately 3,300 procedures were approved to be conducted in ASCs.
ResDAC's faculty who have studied procedures common to ASCs (especially cataract surgery) have found that a large percentage of claims are missed by using only the Outpatient SAF. Therefore, if you are studying any of these types of procedures, it is recommended that you get both the Outpatient SAF and the Carrier SAF. For more information on ASCs, see Chapter 2 of the Medicare State Operations Manual 100-07, and search on "ASC", or MedPAC's informative document, Ambulatory Surgical Centers Payment System.
If your definition of 'outpatient' means care that was provided in a physician's office then you will want the Carrier file.
In the claims files, the residence information is recorded at the time of treatment. In the Denominator file, the information is current as of the time the file is finalized. Hence, if a beneficiary moves between treatment and the time the Denominator file is finalized (end of March of the following year), residence information between the files will not match.
Beneficiary-level linking
You need to submit what's called a 'finder file' to CMS. A finder file contains the identifying information of the individuals in your study that CMS will use to match cases in their data files. The identifying information can be either Health Insurance Claim numbers (HICs) or Social Security Numbers (SSNs).
Other types of linking
If you have census data or any other type of aggregate data, files can be linked based on state codes, county codes (SSA/FIPs crosswalk file is available at CMS's Web site if your counties are recorded as FIPs codes), zip codes or provider numbers, just to name a few possibilities.
Research Identifiable Files (RIFs) can be linked by the unique beneficiary identification number. This number will be randomly generated and assigned to your data files by the CMS contractor producing the file. In the LDS Files, claims and files can be linked using the DESY Sort Key, which is the unique identifier CMS assigns to a beneficiary.
For both the 5% and 100% LDS files, the DESY Sort Key can be used to link files.
Are the same data available in the same format over all the years of my study?
Is the event/procedure I am interested in coded the same across all the years?
Is the event/procedure I am interested in studying treated in the same setting across all the years (e.g. Has it always been dealt with in an outpatient setting)?
Has the event/procedure been covered by Medicare in all the years I'm interested in (e.g. Colorectal screening was not covered until recently)?
The Medicare files contain diagnosis and procedure codes that identify the condition of the patient and the health care procedure provided. For example, the Inpatient SAF contains Diagnosis Related Group (DRG) codes, as well as ICD-9 diagnosis and procedure codes. The Outpatient SAF and Carrier SAF contain ICD-9 diagnosis codes, as well as procedure codes (either the CMS Common Procedure Coding System (HCPCS) codes or for some years, ICD-9 procedure codes). You would have to go to the various coding manuals to determine which codes are needed, as well as determine the setting in which the condition is treated (e.g., inpatient) in order to be able to request the appropriate file(s) and cases.
Yes, but it will be very difficult due in part to data limitations that impact each year differently. Working with experienced researchers and taking courses that provide hands-on introductions to computing, data processing, and quality checking (for example) will give you a much better feel for what's available, and the issues involved in working with CMS data than can be learned on your own. For a list of ResDAC's training opportunities, go to the ResDAC training web page.
Taken in part from Medicare and You 2008: Definition of Terms
Approved Charge (or allowable charge): The amount Medicare determines to be reasonable payment for a provider or service covered under Part B. This includes the coinsurance and deductible amounts.
Assignment: Assignment is an agreement between the beneficiary and Medicare, and doctors, other health care suppliers, or providers to pay a supplier or provider directly for services. Most doctors, suppliers, and providers accept assignment, which is a process in which a doctor or supplier agrees to accept the Medicare-approved charge as payment in full.
Beneficiary: The person eligible to receive, or who is receiving benefits from Medicare, an insurance policy, or a health maintenance organization (HMO).
Benefit Period: Benefit periods are the way that the Original Medicare Plan measures a beneficiary's use of hospital and skilled nursing facility (SNF) services. A benefit period begins the day a beneficiary goes to a hospital or skilled nursing facility and ends when the beneficiary hasn't received any inpatient hospital care (or skilled care in a SNF) for 60 days in a row. If a beneficiary goes into a hospital or a skilled nursing facility after one benefit period has ended, a new benefit period begins. The beneficiary must pay the inpatient hospital deductible for each benefit period. There is no limit to the number of benefit periods, although inpatient mental health care in a psychiatric hospital is limited to 190 days in a lifetime.
Claim Payment Amount: Amount paid to the provider excluding coinsurance and deductibles.
Coinsurance: An amount the beneficiary may be required to pay for services after they pay any plan deductibles. In the Original Medicare Plan, this is a percentage (~ 20%) of the Medicare-approved amount. In a Medicare Prescription Drug Plan, the coinsurance will vary by plan and will depend on how much the beneficiary has spent on medications.
Copayment: An amount the beneficiary pays in some Medicare health and prescription drug plans for each medical service, like a doctor’s visit, or prescription. A copayment is usually a set dollar amount. Copayments are lower for people with Medicaid and people who qualify for extra help. Copayments are also used for some hospital outpatient services in the Original Medicare Plan.
Deductible: The amount the beneficiary must pay for health care or prescriptions, before the Original Medicare Plan, their prescription drug plan, or other insurance begins to pay. In the Original Medicare Plan, the beneficiary pays a new deductible for each benefit period for Part A and each year for Part B. People who qualify for extra help either pay no deductible or a small deductible for prescription drug coverage.
Excess Charge: The difference between the Medicare-approved amount for a service or supply and the actual charge, if the actual charge is more than the approved amount.
Hospice: A program that provides supportive care for terminally ill patients and their families, either directly or by working with a doctor or another community agency.
Lifetime Reserve Days: In the Original Medicare Plan, these are additional days that Medicare will pay for a beneficiary inpatient stay when they are in a hospital for more than 90 days. Each Medicare enrollee has a total of 60 reserve days that can be used during their lifetime. For each lifetime reserve day, Medicare pays all covered costs except for a daily coinsurance.
Limiting Charge: The Medicare limiting charge is set by law at 115 percent of the payment amount for the service furnished by a nonparticipating physician. However, the law sets the payment amount for nonparticipating physicians at 95 percent of the payment amount for participating physicians (i.e., the fee schedule amount). Calculating 95 percent of 115 percent of an amount is equivalent to multiplying the amount by a factor of 1.0925 (or 109.25 percent). Therefore, to calculate the Medicare limiting charge for a physician service for a locality, multiply the fee schedule amount by a factor of 1.0925. The result is the Medicare limiting charge for that service for that locality to which the fee schedule amount applies. (Information from the CMS web site).
Medicare Advantage Plan
(Part C): A type of Medicare health plan offered
by a private company that contracts with Medicare
to provide all Medicare Part A and
Part B benefits. Also called “Part C,” Medicare
Advantage Plans include Health Maintenance
Organizations, Preferred Provider Organizations,
Private Fee-for-Service Plans, Special Needs
Plans, and Medicare Medical Savings Account
Plans. Most Medicare Advantage Plans
offer prescription drug coverage.
Medicare-approved Amount: In the Original
Medicare Plan, this is the amount a doctor or
supplier that accepts assignment can be paid. It
includes what Medicare pays and any deductible,
coinsurance, or copayment that the beneficiary must pay. It may be
less than the actual amount a doctor or supplier
charges.
Medicare Health Maintenance Organization (HMO): A type of Medicare Advantage Plan (Part C) available in some areas of the country. Plans must cover all Part A and Part B health care. Many HMOs cover extra benefits, like extra days in the hospital. In most HMOs, the beneficiary can only go to doctors, specialists, or hospitals on the plan’s list except in an emergency. The costs of care to the beneficiary may be lower than in the Original Medicare Plan.
Medicare Prescription Drug Plan (Part D): A stand-alone drug plan that adds prescription drug coverage to the Original Medicare Plan, some Medicare Cost Plans, some Medicare Private-Fee-for-Service Plans, and Medicare Medical Savings Account Plans. These plans are offered by insurance companies and other private companies approved by Medicare. Medicare Advantage Plans may also offer prescription drug coverage that must follow the same rules as Medicare Prescription Drug Plans.
Medicare Supplement Insurance (Medigap or Medsupp): Health care insurance that pays certain costs not covered by Medicare and meets minimum standards set by state and federal law.
Service Area: The area where a plan accepts members. For plans that require members to use their doctors and hospitals, it’s also the area where services are provided. The plan may dis-enroll a beneficiary if they move out of the plan’s service area.
Skilled Nursing Care: Twenty-four hours-a-day supervision and medical treatment by a registered nurse, under the direction of a doctor.
Skilled Nursing Facility (SNF) Care: This is a level of care that requires the daily involvement of skilled nursing or rehabilitation staff. Examples of skilled nursing facility care include intravenous injections and physical therapy. The need for custodial care (such as help with activities of daily living, like bathing and dressing) does not qualify for Medicare coverage in a skilled nursing facility if that is the only care needed.
Note: Benefit information is correct for 2008. Medicare benefit levels for other years will be different.
Last Modified August 5, 2008