The Carrier claims file was originally called the Physician/Supplier Part B file. This file contains final action claims data submitted by non-institutional providers. These claims are largely from physicians, although they also include claims from other non‐institutional providers such as: physician assistants, clinical social workers, nurse practitioners, independent clinical laboratories, ambulance providers, and free‐standing ambulatory surgical centers. Each record in the Carrier claims file is a claim.
Each carrier claim must include at least one Health Care Procedure Classification Code (HCPCS code) to describe the nature of the billed service. Each HCPCS code on the carrier bill must be accompanied by a line item ICD-9 diagnosis code, providing a reason for the service. In addition, each line item has the fields for the dates of service, reimbursement amount, provider numbers (e.g., NPI), and beneficiary demographic data. Each claim is comprised of up to 13 line items, each of which corresponds to one HCPCS code and its accompanying information.
The most important aspects of the CMS BSA Carrier Line Items PUF 2010 are that it contains carrier line item services for a simple random sample of 5% of the 2010 beneficiary population. Out of approximately 2.5 million beneficiaries in the 5% sample, 1,596,468 had claims, resulting in a PUF of 70,052,393 line items after excluding invalid line items, denied claims and protecting the privacy of Medicare beneficiaries. The line item payments have been rounded and the ICD‐9‐CM diagnosis codes have been coarsened in order to protect individuals from identification while retaining the analytic value of the data. A line item service for a sampled beneficiary is only included in the PUF if the combination of all ten variables is shared by at least eleven line items pertaining to at least eleven beneficiaries and eleven providers in the population. For some combinations of values of the ten variables, however, there are fewer than eleven line items in the PUF. Line items cannot be linked by claim or by beneficiary, and cannot be linked to any external data source by means of the carrier line ID. The carrier line ID is a cryptographic key specific to the CMS 2010 BSA Carrier Line Items PUF and not available elsewhere. The CMS 2010 BSA Carrier Line Items PUF is sorted by this carrier line ID to ensure that the relative positions of each line item in the PUF and in the original source data are totally uncorrelated.
The CMS 2010 BSA Carrier Line Items PUF contains eleven variables: a primary record (i.e., line item) key indexing the line items and ten analytic variables, listed below.
Gender (BENE_SEX_IDENT_CD): 1 = male, 2 = female.
Age (BENE_AGE_CAT_CD): The beneficiary’s age, reported in six categories: 1 = under 65, 2 = 65 ‐ 69, 3 = 70 ‐ 74, 4 = 75‐79, 5 = 80‐84, 6 = 85 and older.
ICD‐9‐CM diagnosis code (CAR_LINE_ICD9_DGNS_CD): International Classification of Diseases, Clinical Modification version 9 (ICD‐9‐CM) is a three‐digit code (four‐digit for “E” ICD‐9‐CM diagnosis codes). In this file 926 such codes are observed.
HCPCS code (CAR_LINE_HCPCS_CD): These are Healthcare Common Procedure Classification Coding System (HCPCS) codes (Level I and Level II) and take on 4,900 possible values in the CMS 2010 BSA Carrier Line Items PUF.
BETOS code (CAR_LINE_BETOS_CD): These are the Berenson‐Eggers Type of Service codes based on clinically meaningful categories of procedures and services. In this PUF, 98 such codes are observed.
Count of services (CAR_LINE_SRVC_CNT): This is the count of the total number of services associated with the line item, ranging from 1 to 999.
Type of provider code (CAR_LINE_PRVDR_TYPE_CD): This variable identifies the type of provider furnishing the service. Examples of provider types include clinics, physicians, and independent laboratories. In this PUF, 6 such codes are observed.
Type of service code (CAR_LINE_CMS_TYPE_SRVC_CD): This variable identifies the type of service. Examples of types of service include medical care, surgery, and consultation. In this PUF, 20 such codes are observed.
Place of service code (CAR_LINE_PLACE_OF_SRVC_CD): This variable identifies the place of service. Examples of places of service include office, independent laboratory, inpatient hospital, outpatient hospital, and emergency room. In this PUF, 28 such codes are observed.
Medicare Payment Amount (CAR_HCPCS_PMT_AMT): Medicare payment is rounded according to the rules in Table 2. Note that a payment amount between $0 and $2.49 is rounded to $0 according to the rounding rules.