Was Jeanne Calment really 122, and why are the oldest ages so hard to verify?

Most experts say yes, though the question has been seriously raised. Jeanne Calment, born in 1875, died in 1997 with a documented lifespan of 122 years and 164 days. She is the oldest person in recorded history whose age has been verified, and the only one verified to have reached 120. She is also unusually well documented: she appears in fourteen census records, starting in 1876 as a one-year-old infant.

Verifying very old ages is hard in general. A supercentenarian is a person aged 110 or older, which approximately one in 1,000 centenarians reaches. Demographers rely on documents, and one study argues that document validation is prone to errors that inflate the number of valid cases. In one so-called blue zone example, 82% of the supercentenarian population turned out to be missing, imaginary, clerical errors or dead when checked.

Calment's case stands out for the opposite reason: it has been checked a great deal. Her age was verified over a full year starting when she turned 120. Still, demographers note that it is an outlier, more than three years beyond the next oldest people documented, where differences are usually months or weeks.

In 2018, Russian researchers Valery Novoselov and Nikolay Zak revived the hypothesis that Jeanne died in 1934 and that her daughter Yvonne took over her identity. Mainstream longevity experts consider it weak: French gerontologist Jean-Marie Robine pointed out that Calment correctly answered questions that her daughter could not have known first-hand, and in September 2019 several French scientists published a paper in The Journals of Gerontology pointing out inaccuracies in Zak's work. A DNA test on a blood or tissue sample could in principle settle it, if a sample were made available.