Genealogy from the perspective of a member of The Church of Jesus Christ of Latter-day Saints (Mormon, LDS)

Thursday, July 3, 2014

IOUSs Explained -- Why you can't merge your ancestors

FamilySearch refers to individuals whose records have been submitted by members of The Church of Jesus Christ of Latter-day Saints many, many times as Individuals of Unusual Size (IOUS). This name is a hold-over from where the number of multiple submission copies of a given individual exceeded the allowable number of combined records.

I think this whole process needs to be explained.

By the way, I would not be surprised to learn that you have to read and re-read this explanation a couple of times. The only reason I understand how all this worked and is working today is because I have lived through it. Bear in mind that I have had this explained to me by many different people, not all of whom knew what they were talking about. This post is my best guess so far as to how all this happened.

To begin the explanation, it is important to realize that the database making up the named individuals in (NFS) came from multiple sources. Those sources included the following:
  • The Ancestral File
  • The Pedigree Resource File
  • The International Genealogical Index (IGI)
  • The Church membership records
  • The existing Temple ordinance records
If records for an individual were submitted in any two or more of these categories, then there were duplicates in the system. For some individuals with numerous descendants in the Church, there could be hundreds of duplicate entries. One problem was that with so many entries it was inevitable that there would be differences in the way the records were recorded. Hence, there could be entries with any number of family member variations, name spellings, dates and places, but all referring to the same person.

NFS tried to resolve these duplicates by using a method of combining records. The idea was to preserve all the information but make a package of all of the differences. Problems began to appear immediately with these individuals that had too many copies in the system. For a reason that remains obscure, FamilySearch cut off the total number of duplicates that could be combined. That total number was changed upward a couple of times, but there were still a significant number of individuals whose duplicate entries exceeded the larger combinatory target number. These individuals are the ones referred to as IOUSs.

That was only the tip of the NFS iceberg. The biggest problem was that users of NFS began combining people who were not the same individual. So we began the process of uncombining (separating) individuals improperly combined.

Now, Family Tree comes on the scene. Theoretically, there is only one place in the Family Tree for each individual. So what happens when Family Tree is using the same database as NFS? The duplicates are still there in the database. Family Tree introduced a "merge" function, so rather than combining the records for duplicate individuals as in NFS, Family Tree merges the individuals and only one is left in the system. Theoretically, again, this should resolve the problem. Except that the merge function did not apply to those IOUS individuals. What about individuals who were improperly combined in NFS? For a while the users could uncombine these individuals in NFS but now what happens? My best guess is that the wrongly combined individuals just come up missing in Family Tree. See Common Family Tree Problems from 11 September 2013 and the comments.

Where does this leave the IOUSs? As long as the two databases, NFS and Family Tree, are using the same data, all the limitations of NFS apply to Family Tree. Hence, nothing can really be done with the extra duplicate ancestors. The problem with this is that the extra people are not just extra people; they are extra entire pedigrees. So making changes to any of the IOUS people is a high risk activity. Your changes may simply disappear when they are finally merged or worse yet, someone could delete the person you are working on.

Yes, Family Tree allows users to delete individuals. There are tons of warning messages but the people do disappear (with all their Temple ordinances attached). So what am I going to do? Continuing waiting. I have been working back about 3 or 4 generations until I get to the level when there are IOUSs and then I am effectively stopped.

Let me know if some of these details are not exactly correct.


  1. Here's an email I got from FamilySearch a couple of weeks ago. It sounds like they are no longer going to uncombine incorrectly combined records. That also means you can't merge two records that are duplicates if one record contains an incorrectly combined person.

    Re: merging LZ17-XCH and 9V55-DMC
    Found: LZ17-XCH has multiple individuals in this record, including Jacob Otthosen. It is also linked to 9v55-DMC as a son, making a merge impossible.

    Thank you for contacting FamilySearch. We appreciate your diligence in maintaining accurate family history records. You have asked us to correct information in Family Tree. Often, correcting or locating information for a certain individual in Family Tree involves separating incorrectly combined records. Currently, the ability to separate or extract information from these records is unavailable. These features in Family Tree are in development, and we ask for your patience as these are made available. We wish you success in your family history endeavors.

    Thank you,


    1. I sounds like what I have been writing about for the past three years or more.