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Two Social Security indexes

They’re not the same, those two indexes on

And the differences can be a bit confusing.

One is titled “U.S., Social Security Death Index, 1935-2014.” The other: “U.S., Social Security Applications and Claims Index, 1936-2007.”

The description of the first index, called the Death Master File by the Social Security Administration and known to genealogists as the SSDI, says: “The file is created from internal SSA records of deceased persons possessing social security numbers and whose deaths were reported to the SSA. Often this was done in connection with filing for death benefits by a family member, an attorney, a mortuary, etc.”1

The description of the second index says the “database picks up where the Social Security Death Index (SSDI) leaves off by providing more details than those included in the SSDI. It includes information filed with the Social Security Administration through the application or claims process, including valuable details such as birth date, birth place, and parents’ names.”2

Two SSA indexes

The first one — the SSDI — has 94,331,864 records. The second, 134,351,623.

So everybody who has an entry in the SSDI should be included in the second, bigger, database plus more, right?

It sure seems like that should be right.

But it’s not.

The collection description itself says so: “While you will not find everybody who is listed in the SSDI in this database, data has been extracted for more than 49 million people.”3

And there are people who are included in that second bigger index who — by all rights — should be included in the SSDI.

And they’re not.

The Legal Genealogist knows that for-personal-sure. Just as one example, my paternal grandfather, Hugo Ernst Geissler, is listed in the second, bigger index, with his Social Security number, his death date and the date of the claim made after his death.4 But he’s not listed in the smaller SSDI at all. He should be — his death was reported to the SSA — but he’s not.

That’s the first part of the confusion, and the only way around it is to make sure we always consult both — and understand that we may not find what we expect.

The second part of the confusion is that not everybody included in the second index is going to have a Social Security number — or any other record at SSA — at all. That’s because the second index often includes the names of the parents of the very first people every to apply for a Social Security number. Their parents were either dead before the system began, or never got a Social Security number, or never lived in the United States.

And I know that for-personal-sure as well. Take the entries for my grandmothers, for example. The Social Security Applications and Claims Index entry for my paternal grandmother, Marie (Nuckel) Geissler, lists both of her parents, neither of whom ever even visited the United States much less applied for a Social Security number here.5 And the entry for my maternal grandmother, Opal (Robertson) Cottrell, lists her father, who died more than two decades before the Social Security program began, and her mother, who never applied for a number.6

So we shouldn’t go off spending our money — which isn’t refundable — asking the Social Security Administration to send us a copy of the application for a Social Security number (otherwise known as the SS-5 form) for everybody who’s named in that second index. We need to understand why the person is named there, and why that may very well not suggest there’s an SS-5 for that person.

Two indexes. Two databases. Not the same.

Cite/link to this post: Judy G. Russell, “Indexing the differences,” The Legal Genealogist ( : posted 5 Apr 2019).


  1. Collection description, “U.S., Social Security Death Index, 1935-2014,” database, ( : accessed 5 Apr 2019).
  2. Collection description, “U.S., Social Security Applications and Claims Index, 1936-2007,” database, ( : accessed 5 Apr 2019).
  3. Ibid., emphasis added.
  4. U.S., Social Security Applications and Claims Index, 1936-2007,” entry for Hugo Ernet Geissler, database, ( : accessed 5 Apr 2019).
  5. Ibid., entry for Marie Nuckel Geissler.
  6. Ibid., entry for Opal E. Cottrell.
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