How Software Errors Corrupt Our Trees



The article I wrote about major problems with new Dutch records on sparked some great discussions both here and on several Facebook groups. People were especially appalled by the error that caused ‘Burgerlijke Stand’ (Civil Registration) to be included in the place name. But this isn’t the biggest error caused by software.

I found almost 1 million records for people who lived in Reusel-De Mierden, Noord-Brabant, Netherlands in Ancestry Member Trees, many going back to the 16th or 17th century. That is remarkable for a tiny municipality that has only existed since 1997! I estimate that at least 900,000 of these records should say “Holland” instead of Reusel.

Another error causes Dutch place names that had “NL” to be resolved to “Newfoundland and Labrador, Canada” instead of “Netherlands”. These errors are pretty obvious, since the  place name will say something like “Amsterdam, Noord-Holland, Newfoundland and Labrador, Canada.” I searched for the names of all Dutch provinces with Newfoundland behind it and found over 100,000 incorrect profiles.   

The error that has had the least impact so far, is the one where ‘Burgerlijke Stand’ (Civil Registration) is included in the place name in the index and found its way to member trees from there. I found about 2,300 people with birth places with ‘Burgerlijke stand’ in it so far. But this record set has only been online at since earlier this week so unfortunately this error has some serious potential for growth.

I chose to check Ancestry Member Trees because that is the largest collection of family trees that I know of. This isn’t meant to imply that the errors originated with But the friendly way in which Ancestry lets you accept hints from other trees probably caused these errors to spread fast once an error made its way to a Member Tree.

It’s easy to see how people would be tempted to replace a generic place of origin like ‘Holland’ by the specific town in Noord-Brabant where the immigrant ancestor came from. A place name as specific as ‘Reusel-De Mierden, Noord-Brabant, Netherlands’ doesn’t appear like somebody made it up…

Check your trees!

I advise you all to take a moment to check your trees for any of these errors. Please leave a comment below if you find any. You won’t be alone, I promise!

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About Yvette Hoitink

Yvette Hoitink, MLitt, CG®, QG™ is a professional genealogist, writer, and lecturer in the Netherlands. She has a Master of Letters in Family and Local History from the University of Dundee, and holds the Certification of Genealogist and Qualified Genealogist credentials. Yvette served on the Board of Directors of the Association of Professional Genealogists and won excellence awards for her articles in the National Genealogical Society Quarterly and the Association of Professional Genealogists Quarterly. Yvette has been doing genealogy for over 30 years. She helps people from across the world find their ancestors from the Netherlands and its former colonies, including New Netherland. Read about Yvette's professional genealogy services.


  1. Virgil Hoftiezer says

    That is so bad, but may explain some of the major errors we see in some trees on
    Unfortunately it is impossible to remove these errors — once on the internet it must be absolutely true.
    Thanks for alerting us to these horrible errors.

  2. Good job Yvette!
    And for all researchers. ….please don’t copy data just like that…..check and double check before you do!

  3. Yvette, I disagree. It’s not software (errors) that corrupt trees, it’s the user!

    If software automatically changes your data, than you would have a point. But in the case of the hints, it’s the user that pushes the acknowledge button without checking / correcting the data. The software functionality here is not to blame, it’s not in error. The hint might be incorrect because the software uses an incomplete geographical dataset, I hope users will help getting these datasets complete, for example via the Wikipedia like

    The ‘Burgerlijke Stand’ issue has another dimension to it. You can blame FamilySearch, as their dataset contains these (rather easy to spot!) errors. But Ancestry (and MyHeritage as they have also partnered with FamilySearch), should they check and correct the data? I think they (and again, also the users) should inform FamilySearch, so the source gets corrected, all parties using these datasets then also get corrected data.

    Finally, I’d like to repeat what Irma says: researches, always check and double check information you find and use, be it from an archive or library, offline or online publication.


    • Hi Bob,

      Thanks for stopping by.

      The problem with Reusel-De Mierden is that it is the software that automatically replaced all references to ‘Holland’ with ‘Reusel-De Mierden, Noord-Brabant, Netherlands’ if you chose to geocode the place names. At least, that is what Family Tree Maker used to do. Users were not presented with the new names and asked if they wanted to accept it if they chose batch mode, the program just changed all the instances automatically.

      Same with “, NL” being replaced by Newfoundland and Labrador, Canada. I think that was a global search-and-replace gone horribly wrong at the index level. You can debate whether or not that is a software problem or a human error, but that error wasn’t made by the compiler of the tree but by the compiler of the data (or one of their database administrators). With ‘Burgerlijke Stand,’ I don’t know if it was a database design error, conversion error or data entry error but whichever it was, the resulting database isn’t normalized so information that should be in two separate fields are combined into one. Once again, that is the raw material that the users are presented with. And yes, people should be more careful about what they accept, but how is an American to know that there is no village ‘Burgerlijke Stand’ in Arnhem?

      As I tried to explain in the text underneath the infographic, I did not mean to blame for these errors. Users blindly accepting hints aggravate the problem, but are not the root cause. They do make them more visible.

  4. If it wasn’t so sad one could laugh about these boo-boos. But I am grateful for the use of your infographic. Thanks!

  5. I have also re-posted the infographic in my blog. As Peter said, if it wasn’t so sad, it would be funny. And it is one reason, why I don’t put up my tree at Ancestry

  6. Yvette,
    I am also reposting your infographic, thanks. And, yes, I’ve noticed for years now that I must be careful not to assign my Winterswijk ancestors to Canada! I didn’t realize why it was happening; I assumed there must be a town or other area in Newfoundland and/or Labrador with the same name.

  7. Aliosn Orsborne says

    Hi Yvette,

    I think the ‘Holland’ error comes from the UK census forms . For example, my 2nd Great- Grandfather, Myer Hartog Zilver, was born in Amsterdam but emigrated to the UK in 1837. In the 1841 census he’s noted as being from ‘Foreign Parts’ but in 1851, 1861 and 1871 his country of origin is ‘Holland’. I suppose people who don’t know much of the history would then search for Holland.

    I was given quite a lot of family tree information by a cousin. That contained quite a lot of errors, but I didn’t know about the Reusel one. All now changed to Netherlands!

    Thank you,


    • “Holland” is used internationally quite a lot as reference to the Netherlands; not just on UK census records but it many others too. The problem is that FamilyTreeMaker did not know this as an alternative name for the Netherlands and resolved it to a street name.


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