SEER-Medicare: Medicare Claims Files
For Medicare beneficiaries with fee-for-service coverage, claims data are
available for both the cancer and non-cancer cohorts from 1991-2006, with the
exception of hospital data (MEDPAR) that are available from 1986 (see Summary Table of Available Data).
The Medicare files provided as part of SEER-Medicare are described below and
reflect input from staff at NCI and CMS.
Medicare Provider Analysis and Review (MEDPAR)
The MEDPAR file includes all Part A short stay, long stay, and skilled nursing facility
(SNF) bills for each calendar year. MEDPAR contains one summarized record per admission.
Each record includes up to 10 ICD-9 diagnoses and 10 ICD-9 procedures provided during the
hospitalization. MEDPAR files are finalized 3 years following the close of the calendar
Researchers interested in only short-stay hospitalizations will need to subset the
MEDPAR file using the variable 'MEDPAR short stay/long stay/skilled nursing facility (SNF)
indicator code' located in column 44 ('S'=short stay, 'L'= long stay and 'N' = skilled
In almost all cases, a single MEDPAR record reflects a summary of all care provided
during an institutional stay. However, if the stay is long, there may be more than one
claim per stay. This occurs most frequently for stays in SNFs as these often span several
months. SNFs records often have no discharge date as persons remain in institutions
beyond the period of Medicare coverage.
Several fields on the MEDPAR file are not considered reliable:
- source of admission
- discharge destination
- group health organization payment code
Documentation for MEDPAR is available in PDF format.
Carrier Claims (old file name Physician/Supplier Part B (NCH))
Since 1991, the Center for Medicare & Medicaid
Services (CMS) has collected physician/supplier (Part B) bills for 100 percent of all
claims. These bills, known as the National Claims History (NCH) records, are largely from
physicians although the file also includes claims from other non-institutional providers
such as physician assistants, clinical social workers, nurse practitioners, independent
clinical laboratories, ambulance providers, and stand-alone ambulatory surgical centers.
The claims are processed by carriers working under contract to CMS. Each carrier claim
must include a Health Care Procedure Classification Code (HCPCS) to describe the nature of
the billed service. The HCPCS is composed primarily of CPT-4 codes developed by the American Medical Association, with additional codes
specific to CMS. Each HCPCS code on the carrier bill must be accompanied by an ICD-9
diagnosis code, providing a reason for the service. In addition each bill has the fields
for the dates of service, reimbursement amount, encrypted provider numbers (e.g., UPIN),
and beneficiary demographic data.
Because of the large number of carrier claims, CMS maintains the data in variable
length files. IMS, NCI's programming contractor, has converted these records into fixed
length files by creating a record for each service that appears as a trailer on the CMS
record. As a result, there may be multiple records for the same date of service. For
example, if a person saw his/her doctor for an office visit and had a chest x-ray as part
of the visit, there would be two different records for the same date of service, one for
the office visit and the other for the chest x-ray.
Carrier Claims Details:
- Carrier claims are non-institutional claims, however this does not mean that they are
outpatient claims. Providers, such as physicians, can bill for services provided in the office, hospital, or
other sites. To identify where the service is provided, one needs to assess the variable "line
place of service" (columns 210-211), which specifies the place of service.
- There are two pairs of date fields on the carrier file. The fields "claim from" and "claim
through" dates (Cols 51 and 59) fields cover a period of service (usually but not always a single date of
service), while the "line first expense date" and "line last expense date" (Cols 212 and 220) reflect the
specific day of service.
- For every billed procedure (using a HCPCS code), there should be a corresponding ICD-9
diagnosis code (often called the line item diagnosis) that provides the reason for the billed service. In the
case of lab tests, the diagnosis will often be XXOOO because the outside lab has no information from the
physician about the reason for the test. In addition, the carrier claim contains space for 4 diagnoses, known as
"header" diagnoses. These are not necessarily linked with any of the procedures but may reflect co-existing
health conditions. The accuracy of the diagnoses on the carrier data has not been determined.
- Selected services may not appear in the carrier claims, even if they have been provided.
For example, CMS pays physicians a fixed amount for surgeries, a payment practice known as bundling. As part of
bundling, CMS expects that certain care will be included in the payment amount, such as the first one or two
office visits following surgery or a biopsy just before surgery. Bundled services will not appear in the
physician data. Interpretation of the rules on bundling varies by carrier.
Documentation for Carrier Claims is available in PDF format.
The outpatient file contains Part B claims for 100 percent for each calendar year from
institutional outpatient providers. Examples of institutional outpatient providers include
hospital outpatient departments, rural health clinics, renal dialysis facilities,
outpatient rehabilitation facilities, comprehensive outpatient rehabilitation facilities,
community mental health centers. In and out surgeries performed in a hospital will be in
the hospital outpatient file, while bills for surgeries performed in freestanding surgical
centers appear in the carrier claims, not in the outpatient file.
Some of the information contained in this outpatient file includes diagnosis and
procedure codes, dates of service, reimbursement amounts, facility provider number,
revenue center codes and beneficiary demographic information. Although the outpatient file
contains data fields for ICD-9 diagnosis and procedure codes, the reporting of these codes
is sporadic. Services from the outpatient bill are captured from HCPCS codes and from the
revenue centers. Definitions for revenue center codes may be obtained by contacting ResDAC
or CMS directly.
As with the carrier data, there may be multiple records for the same date of service.
Additionally, data related to each revenue center on a claim are written to a separate
record. Although payment amount specific to a revenue center is not available, the claim
total charge amount and payment amount are repeated on every record that originated from
the same claim. It is important, therefore, that the file is sorted by regcase, link_num
and seg_num, and that the first record in the sort (if first link_num;) is kept in order
to eliminate duplicate charge and payment amounts from the file. Sorting on seg_num in
addition to regcase and link_num is necessary because CMS inserted "0" for the total
charge and payment amounts on records with seg_num > 0.
Documentation for Outpatient Claims is available in PDF
Home Health Agency (HHA)
The Home Health Agency file contains 100 percent of all claims for home health
services. Some of the information contained in this file includes the number of visits,
type of visit (skilled-nursing care, home health aides, physical therapy, speech therapy,
occupational therapy, and medical social services), diagnosis (ICD-9 diagnosis), the dates
of visits, reimbursement amount, HHA provider number, and beneficiary demographic
information. An HHA bill may cover services provided over a period of time, not a single
Researchers using the Home Health Agency data need to be aware of changes over time in
how CMS codes HHA services. Prior to January 1998, all HHA visits associated with a
particular type of service were entered once for each month. The Revenue Center Unit Count
on the claim captured the number of visits in that month. Beginning with May 1998, CMS
entered each visit separately, meaning that when the variable-length record is rewritten
to a fixed length file, there will be a separate record for each HHA visit. Claims from
February through April of 1998 were either coded under the old or new method during these
transitional months, with April showing the biggest change. In addition, in July 1999,
there was a change of what is captured in the Revenue Center Unit Count field. This
field now captures the number of fifteen (15) minute segments of time spent on each visit.
However, it is not thought to be reliable until October 1999.
Based on these observations, we recommend that the number of visits for a specific
service (revenue center code) be counted in the following way:
- For data through April 1998, the number of visits is the sum of the Revenue Center Unit Counts.
- For data beginning in May, 1998, number of visits is the number of fixed-length records with that revenue center code.
Documentation for the HHA file is available in PDF format.
The Hospice file contains claims data submitted by Hospice providers. Some of the
information contained in this file includes the level of hospice care received (e.g.,
routine home care, inpatient respite care), terminal diagnosis (ICD-9 diagnosis), the
dates of service, reimbursement amount, Hospice provider number, and beneficiary
demographic information. Hospice files are maintained in the format described for HHA
Documentation for the Hospice file is available in PDF
Durable Medical Equipment (DME)
The Durable Medical Equipment (DME) contains final action claims data submitted to
Durable Medical Equipment Regional Carriers (DMERCs). Some of the information contained in
this file includes diagnosis, (ICD-9 diagnosis), services provided (HCFA Common Procedure
Coding System (HCPCS) codes), dates of service, reimbursement amount, DME provider number,
and beneficiary demographic information. Claims for DME services that are processed by a
carrier will be found in the NCH file. Claims for DME services that are processed by
DMERCs will be found in the DME file. For example, claims for oral equivalents of IV
chemotherapies will be found in the DME file.
Documentation for the DME file is available in PDF format.
The appendix file contains information on variables like BIC, revenue center code,
state and other variables which are found in the claims data.
The appendix file is available in PDF format.