Denominator File - LDS

The Limited Data Set (LDS) is the same as our previous BEFs with the exception that the HIC is completely blank in the LDS.

The DESY-SORT-KEY is the unique beneficiary identifier field in the LDS files. It will be consistent within the file, across files, and across time, but cannot be used for any other purpose and will not be accepted for search for other CMS data. The DESY-SORT-KEY is provided within 50-bytes generated by DESY and added at the end of the base (or fixed portion) record of each claim. This does not affect the statistical quality of the data as the properties of the data and relative proportions are still the same. In other words, an identified cohort of patients (by diagnosis code as an example) is still the same.

The Denominator File combines Medicare beneficiary entitlement status information from administrative enrollment records with third-party payer information and GHP enrollment information. The Denominator File contains data on all Medicare beneficiaries enrolled and/or entitled in a given year. It is an abbreviated version of the Enrollment Data Base (EDB) (selected data elements). It does not contain data on all beneficiaries ever entitled to Medicare. The file contains data only for beneficiaries who were entitled during the year of the data. These data are available annually in May of the current year for the prior year.

File Cost:  5% File, $250.00 per year   Media: CD ROM
               100% File, $1,005 per year  Media: DVD    

Data Format: CSV format with SAS® read-in program
Available:  CY 1999 through CY 2008

Instructions on How to Request LDS Data Files in the Related Links Inside CMS section below.