I'm Dutch, most of my ancestors are Dutch, and I speak Dutch. So I use a Dutch genealogy program named Aldfaer. In the Netherlands many surnames have a prefix like "van de", and Aldfaer provides for an extra field between the first name and the surname which is a bonus.
Aldfaer also has a menu option "Controleer Gegevens..." (Check Data). It analyses the loaded genealogy file, and gives a list of people with unlikely dates. When I click on one of the shown persons in bold, the program loads that person, so I can adjust the error. In the example below, Aleid was still alive on 15 October 1294, so I was able to solve the error by correcting her death date.
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| Aldfaer explains that Aleid died before her younger children were born |
The website of Tree Prism features a similar service in its Analysis menu. You start with exporting your genealogical data to a gedcom (.ged) file. On the Tree Prism website you chose the generated .ged file from your disk. The site promises the file will be processed in the browser, and not uploaded. Even with a large file, the analysis is fairly quick.
The "Analysis" Tab can be found in the upper right section of Tree Prism website. It shows a list of people with unlikely dates. In this case you will have to find the listed persons in your genealogy database.
In the first example, Tree Prism showed a father Hendrick with a death year, and his daughter Janneken's birth year, that were too far apart. Hendrick died between 18 February 1581 and 3 March 1584, so Jenneken's birth year should be earlier than 1582. Janneken's youngest known child, a daughter Neeltgen, was baptised on 23 September 1618, so a birth year around 1580 is possible for Jenneken.
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| Tree Prism example with a daughter's birth date and father's death date that are too far apart |
In the next example, Tree Prism showed a man who seems to have been married long before his birth. In this case the problem is not the marriage year, the problem is Cornelis' birth year - he can't have been born after his death. Cornelis was born a century earlier. He married Marrij Claes around 1585. Subsequently, he married his second wife, Pleunke Jacobs Geerards, around 1608. By July 1628, Cornelis had died. It was his birth year that was wrong.
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| Tree Prism example that the birth year of Cornelis Adriaensz Nelemans was in the wrong century |
Additionally, in the menu on the left, the option at the bottom is "Longevity". This option first shows some age statistics of the people in your uploaded .ged file. When you scroll down, you also get a list with "Longest Lives". That list, too, can be used to check if the dates of the listed people are valid.
