I looked up the marriage between Lilly Axel and John J. Corper in the NY marriage index, and found this record.

The wedding occurred on Dec 25 1919, and was registered in early 1920.

I then ordered the microfilm for FHL roll #1644060 and looked up marriage certificate #1280, to discover that it listed the wrong couple. In fact, examining the dates on the certificates of film #1644060 suggests that it is from the beginning of 1921, not from 1920. Retroactively looking at the FHL listing for this film, it indeed shows that the roll contains certificates 501-1750 from 1921. The correct film (assuming the certificate number is right) seems to be 1643530.

My questions:

  1. How common are such errors (off by a whole year!)?
  2. How trustworthy is the certificate number?
  3. What was the indexing process that led to such errors?
  4. What is the most effective way to notify IGG (the keepers of that database) to update it?
  • Your first two questions seem rather subjective.
    – Luke_0
    Dec 3, 2012 at 19:49
  • I think collectively, people should have a decent handle on the frequency of errors in the two numbers. I am looking for something like 1% or 0.001% or whatever. If a bunch of people ordered films and never saw an error of either kind, that would be reassuring that this is a fluke. If others also encountered similar issues, that would be a caveat for future searches to always cross-check the film number with FHL. Dec 3, 2012 at 21:54
  • Gene, did you mean to say you are not looking for a percentage, or did you really mean that you are? While I can give you my opinion from 10+ years of experience that errors in the NYC vital records indexes are extremely rare, I'd just be making up a number if I tried to give you a percentage. I doubt anyone here will be able to give you such a percentage with any kind of authority.
    – efgen
    Dec 4, 2012 at 4:53
  • Extremely rare is a good point of reference. As opposed to "oh, it happens once or twice a year." I wanted to gauge the rarity of the event. Dec 4, 2012 at 4:57

1 Answer 1


The NYC groom index on ItalianGen was transcribed from a microfilm index that was created many years ago. The NYC bride index was partially transcribed from the microfilmed index -- the original index was missing some years, so the ItalianGen volunteers filled in the gaps by creating an index for those years from the actual records.

Errors could have happened in the original indexing or in the transcription to the ItalianGen database. From my own experience in working with both the original indexes and the ItalianGen index (I've been doing NYC research for 10+ years), I would say errors are rare.

That said, this doesn't appear to be an error in the indexing of the marriage record itself. The microfilmed indexes don't include the FHL film numbers. In fact, ItalianGen doesn't even provide the FHL film numbers.

You accessed the ItalianGen database through SteveMorse.org -- the FHL film numbers are only provided through that interface.

I can't speak authoritatively about the inner workings of Steve's site, but I would guess that he created his own database of the FHL film numbers from the FHL catalog and uses that database to look up the film numbers for each certificate in the search results.

So report the error to Steve Morse. His email address is on his website.

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