A Bayesian Assessment of the Longevity of Jeanne Calment

Mme Calment died in 1997 at the reputed age of 122 years, the longest validated life span of all time. Recently it has been suggested that in fact Mme Calment was not Jeanne Calment born in 1875 as believed, but rather her daughter Yvonne born in 1898. She could have swapped identity on her mother's death in 1934. In this study, the most reliable evidence is evaluated and competing versions of hypothetical scenarios are compared. No information is completely certain so only probabilities are considered. Methods of Bayesian inference are used to assess the probability of correctness for each scenario. It is not possible to form a definitive conclusion with the evidence currently available, but we believe that the outcome reinforces earlier suggestions that Mme Calment's age validation is unsafe in the light of recent evidence and should be reviewed. Indicators from DNA analysis that could reliably resolve the question of whether or not an identity switch took place are provided. The methods of Bayesian inference used here could be applied to other longevity validations to improve the validation process for longevity.