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Date of Death

A beneficiary’s date of death is available in the Master Beneficiary Summary File (previously known as the Beneficiary Summary File or Denominator) and the Vital Status File. For beneficiaries that die during an inpatient or skilled nursing facility stay, date of death is also available on the MedPAR file.

CMS receives death information from a number of sources. The main sources CMS uses to develop its death information are:

  • Medicare claims data from the Medicare Common Working File (CWF)
  • Online date of death edits submitted by family members
  • Benefit information used to administer the Medicare program collected from the Railroad Retirement Board (RRB) and the Social Security Administration (SSA)

Because of the variation in sources of information sometimes only the month and year of death are reported to the enrollment data and the exact day of death is not known. In these cases, the death day is set to the last day of month.  See below for information on how to identify these cases.

Death Variables

There are three death-related variables in the Medicare enrollment data:

  • Date of Death (BENE_DEATH_DT)
  • Valid Date of Death Switch (BENE_VALID_DEATH_DT_SW):

This variable indicates that day within the month of death has been validated. When the day of death within the month has not been validated, the death date is set to the last day of the month of death. Therefore, if there is a date included in the “Date of Death” variable, the “Valid Date of Death Switch” should be checked to see if the exact day has been validated. A value of “V” indicates the day has been validated.  Otherwise, the field is blank. 

Overall, 99% of death days have been validated. However, within the RRB (Railroad Retirement Board) beneficiaries, the validation rate was < 30% until the last few year (see chart below).  RRB beneficiaries comprise a very small percentage of all Medicare beneficiaries; approximately 2% of all beneficiary deaths are RRB beneficiaries and 98% are SSA beneficiaries. 

  • NDI (National Death Index) Cause of Death

The NDI cause of death information is currently available for Medicare deaths that occurred between 1999 and 2016.

Death information within enrollment data files

Master Beneficiary Summary File (MBSF)

The Master Beneficiary Summary File Base segment contains:

  • Date of Death: Deaths are limited to those that occurred during the specific enrollment year. For example, the deaths in the 2010 MBSF all occurred in 2010.
  • Valid Date of Death Switch: A value of "V" means that the day has been validated. Otherwise, the field is blank and the Date of Death will be automatically set to the last day of the month. If your research project requires an exact date of death, use the "Valid Date of Death Switch" to see if the exact day has been validated.


Overall, 99% of death days have been validated. The most common reason for no validation is that the death information came from the Railroad Retirement Board (RRB).  Until recently, the validation rate among RRB beneficiaries was < 30% (see chart below).  However, RRB beneficiaries comprise a very small percentage of all Medicare beneficiaries; approximately 2% of all beneficiary deaths are RRB beneficiaries and 98% are SSA beneficiaries.

The Master Beneficiary Summary File NDI segment contains:

  • NDI Date of Death: The verified date of death according to the death certificate. Deaths are limited to those that occurred during the specific calendar year.
  • NDI cause of death: The cause of death according to the death certificate. Cause of death information is available by ICD-10 code or as recoded categories.

The NDI cause of death information is currently available for Medicare deaths that occurred between 1999 and 2016.

Vital Status File

The Vital Status File contains:

  • Date of Death: This is the most up-to-date death information and contains death dates for any year up to the time the file is created. 

The Vital Status File is a cumulative file, rather than an annual file.  It will contain the most up-to-date death information as of the time the file is created for the researcher.  This file may be useful for researchers who want death information after the period for which they have enrollment data. For example, a researcher may have enrollment data for 2014-2015 and wants the most recent death information for the cohort, but does not plan to purchase additional enrollment data. The Vital Status file would give the most current date of death information up to and including the date the file was created.

Due to the lag time between deaths and the date they are reported to Medicare, the deaths in the few months nearest the Vital Status File creation date will not be completely identified.  The vast majority of deaths are known to Medicare within 2-3 months. 

The Vital Status file does not include information on whether or not a death date is validated.  A comparison of the MBSF and Vital Status files has confirmed that death dates that are not validated within the MBSF are the same dates as in the Vital Status file.  I.e, the Vital Status file is accurate for month and year of death but if the day of death is the last day of the month, the death date may not be accurate.  However, as noted above, the percent of non-validated deaths is very small in recent years.

Percent of death dates validated by year and SSA vs. RRB retiree
Chart 1
Variables related to date of death in utilization data files

MedPAR

If a death date is present in the enrollment database at the time the MedPAR is created, it is included in the file. The death date is not necessarily limited to the calendar year of the MedPAR. For example, the 2016 MedPAR file may contain some dates of death in 2017; however, deaths that occurred in 2017 after the MedPAR file was created will not be included.

The MedPAR also contains a code indicating whether the death date has been verified by the Social Security Administration’s Master Beneficiary Record (MBR) or whether the death date was indicated on a claim but was not verified. A value of ‘V’ indicates that the death date has been verified by the MBR, a value of ‘B’ indicates that the death date was provided to the enrollment database from a claim. A value of ‘N’ indicates that neither ‘B’ nor ‘V’ apply but the beneficiary had claim status code that indicated death during a stay. In general, 98% percent of records are verified, and in the most recent years fewer than 0.5% of MedPAR records with a date of death are not verified.

When present, the MedPAR date of death matches the MBSF date in 99.9% of stays; when they do not match, the MBSF death date is usually not validated.

Only beneficiaries with an inpatient discharge or skilled nursing facility admission during the calendar year will have death information in the MedPAR.