I present a body of data that, I argue, cumulatively casts serious doubt on the validity of Jeanne Calment's accepted world record of human life span. First, I assess the plausibility of the record based on the life spans of other centenarians in the International Database of Longevity (IDL) and critique some arguments put forward previously in support of that plausibility, including the longevity of Calment's ancestors. Second, I review the literature dedicated to Calment and discuss multiple contradictions in her interviews, biographies, photos, and documents. I argue that the evidence from these sources motivates renewed consideration of the previously rejected hypothesis that Jeanne's daughter Yvonne acquired her mother's identity after her death to avoid financial problems and that Jeanne Calment's death was reported as Yvonne's death in 1934. Finally I discuss the importance of reconsidering the principles of validation, due to the possibility of similar problems regarding other exceptionally long-lived people and the mistaken inferences that researchers may draw from flawed datasets. The phenomenon of Jeanne Calment may prove to be an instructive example of the uncertainty of seemingly well-established facts.

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.

Background: The ages of the oldest humans are important data for scientific studies in gerontology, medicine and demographics. Scientists often reference specific cases such as Jeanne Calment, or resources such as the International Database on Longevity. However, numerous inherent dangers and pitfalls have dogged the history of human longevity record keeping. Many people who were believed to be the oldest person in their day turned out to be younger than claimed. This could affect scientific conclusions based on their assumed longevity. In this work we review longevity validations at the top of the official lists of the world’s oldest ever men and women. We aim to outline a stronger “cast-iron” standard for the purposes of future scientific studies of extreme longevity.Results: To inform the higher standard, we have examined individual cases of validation, including those that have been withdrawn or disputed. We highlight their weaknesses and show how deeper investigation could help validate similar claims in the future. We also consider the use of DNA testing to verify the identity of supercentenarians. A self-use questionnaire is offered to validators to help further improve consistency and completeness of their reporting.In a few cases, such as the lives of Sarah Knauss, Christian Mortensen and Israel Kristal we have found new evidence that improves confidence in their validation, but for others our search casts serious doubt on authenticity, or leaves questions over whether the standard of validation is good enough. Having previously disputed the longevity of Jeanne Calment, we now add Nabi Tajima from Japan and Johnson Parks from the U.S. to those who should be invalidated, and we question whether birth records for Japanese supercentenarians can be considered reliable. We also challenge the validation of several U.S cases which were based on unreliable census data in the SSA Kestenbaum study.Conclusions: Correct assessment of the chronological age is a necessary step for biologists studying the determinants of exceptional longevity. We hope that our findings could be used to improve the quality of age validations. They may also influence demographers' conclusions about the future of life expectancy

Madame Calment’s extraordinary longevity claim has significantly influenced current estimates of human lifespan. However, recent evidence raises doubts about the authenticity of her record. We compare two competing hypotheses: the base scenario, which assumes that Jeanne’s daughter Yvonne died in 1934, and the switch scenario, which proposes that Yvonne assumed her mother’s identity in 1933. Our analysis suggests that the available evidence supports the switch scenario and contradicts the previously accepted base scenario. This study emphasizes the need to re-evaluate the evidence and highlights the importance of DNA testing (subject to approval by the French authorities). The case of Jeanne Calment was considered the gold standard for age validation. Our research shows that documentation is not always sufficient to verify cases of exceptional longevity. This has important implications for our understanding of the upper limits of human lifespan and demographic patterns in extreme ages.