Date Information in the Limited Data Set (LDS) Medicare Claims Files

Date Information in the Limited Data Set (LDS) Medicare Claims Files

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Please note that the information below applies to the claim-level files, but not to the stay-level file (the LDS MedPAR).

 The contents of date fields in the Limited Data Set (LDS) claims files will depend on the claim year. Prior to 2009, the dates are stored as quarter and year only, but in more recent years, the dates are stored as month, day, and year. RIF (Research Identifiable File) dates are month, day, and year for all file years.

 2008 and Earlier

Date fields in 2008 and earlier contain a quarter and a year. For example, a 2/15/2007 hospital admission date will be recorded as 107 (1st quarter, 2007). It is not possible to obtain month, day, and year dates for 2008 and earlier LDS claims.


For the 2009 data, there are “date files” that can be linked to each of the seven claim types (HHA, Hospice, SNF, Inpatient, Outpatient, Carrier, and DME). LDS users can link the date files with the claims files to add month, day, and year dates to their data. The date files are not automatically sent out with the claims files for 2009; these must be requested in addition to the claims files. There are separate date files for the 5% and 100% files and for each of the seven claim types. Pricing information for the date files can be found on the LDS Order Form.

2010 and Forward

Beginning with the 2010 data, month, day, and year dates are included in the claims rather than quarter and year. LDS users will not need to request date information separately.

Although the LDS claims date fields now contain month, day, and year, there were and are fewer date fields in the LDS claims than the RIF claims for all claim years.  For example, the RIF data contain Claim From Date and Claim Through Date, while the LDS data contain Claim Through Date only, which limits a researcher’s ability to discern precise dates of services and procedures. For more detail about the difference between the contents of the RIF and LDS claims, please see the Knowledgebase article “Differences between RIF, LDS, and PUF Data Files.”   


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The analyses upon which this publication is based were performed under CMS Contract Number HHSM-500-2005-00027I
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The process and materials mentioned as part of this KnowledgeBase article are current, as of the publication date on the article, to the best of our knowledge. The examples provided are correct in the aggregate but may not apply to every subgroup or circumstance that a researcher may wish to study. It is up to the researcher to conduct analysis and confirm that the patterns described in this KnowledgeBase article apply to his/her particular study. If your research findings appear to contradict the advice provided, please contact ResDAC at