<story><title>Supercentenarians are concentrated into regions with no birth certificates</title><url>https://www.biorxiv.org/content/10.1101/704080v1</url></story><parent_chain><item><author>mktmkr</author><text>There is also the reverse process: people who are older than officially recorded.  When my in-laws came to the USA from Vietnam after the war they wanted to be able to work for a long time before anyone forced the to retire, so they just said they were 25 years old, an understatement of quite a number of years.  Upheaval and displacement tend to wipe out government records.</text></item></parent_chain><comment><author>grawprog</author><text>We found this out about my grandma near the end of her life. Everyone had always thought she&amp;#x27;d been born in 1927. Turns out,  according to some paperwork we&amp;#x27;d gotten from her home country she&amp;#x27;d actually been born in 1923. It was all because she wanted to lie to my grandpa and seem younger than she was. At some point she just forgot about it.</text></comment>
<story><title>Supercentenarians are concentrated into regions with no birth certificates</title><url>https://www.biorxiv.org/content/10.1101/704080v1</url></story><parent_chain><item><author>mktmkr</author><text>There is also the reverse process: people who are older than officially recorded.  When my in-laws came to the USA from Vietnam after the war they wanted to be able to work for a long time before anyone forced the to retire, so they just said they were 25 years old, an understatement of quite a number of years.  Upheaval and displacement tend to wipe out government records.</text></item></parent_chain><comment><author>o09rdk</author><text>I kinda wondered that looking at the paper. It&amp;#x27;s hard to know from eyeballing such low numbers relatively speaking, but it seems like there&amp;#x27;s not only a large peak in supercentenarians born shortly before the introduction of records (suggesting erroneously reported very old age), but maybe also a smaller peak &lt;i&gt;after&lt;/i&gt; the records.&lt;p&gt;With name databases, there seems to have been a phenomenon where people retroactively created records when they were introduced (e.g., people registered for SSNs after the fact). Maybe there&amp;#x27;s something similar going on: people are overreporting their age when born with no records, but also are overreporting their age when they registered their birth after the fact.&lt;p&gt;It&amp;#x27;s a bit hard to explain in terms of underreporting age, and the trends are such that I think they still largely support the authors&amp;#x27; hypotheses in terms of relative overreporting and underreporting. But I agree there&amp;#x27;s probably more fuzziness here.&lt;p&gt;The bigger issue for me that this raises are the perils of making inferences on outliers of any distribution. The further out you go on any characteristic, the more likely you are going to run into similar problems with errors, fraud, or unusual circumstances.</text></comment>