France 2017 Death Certificate Redesign Doubled Medicolegal Investigations and Sharpened Mortality Data

A quiet redesign of the French death certificate in 2017 has produced one of the clearest pieces of evidence yet that a simple form change can measurably improve the quality of national mortality statistics. A study published in the International Journal of Legal Medicine analyzed 2,425,207 death certificates filed in France between 2016 and 2019 and found that the revised certificate more than doubled the likelihood that a death received a medicolegal investigation, while also increasing the precision of the international disease codes assigned to causes of death by nearly ten percent nationwide. Because the reform altered the instructions on the certificate itself rather than the workforce that fills it out, the researchers were able to treat the rollout as a natural before-and-after experiment testing whether more specific guidance functions as a form of on-the-job training for physicians.

The stakes are higher than the administrative paperwork might suggest. Distinguishing between types of deaths matters for two central reasons: it allows epidemiologists to understand and prevent them, and it is essential to bringing justice to homicide victims. Decades of research have documented the many ways in which determining the manner of death can go wrong, yet the most common policy responses, calls for more training and more resources, have largely never been put to an empirical test. Aside from work on cognitive bias mitigation, the authors note that they are not aware of studies demonstrating that these widely recommended remedies actually work. The French reform offered a rare opportunity to measure the effect of added guidance directly.

The French system differs from the American one in ways that make such a test possible. In the United States, medicolegal professionals become involved automatically when a death falls into specific categories. In France, involvement must be triggered by the physician who ascertains the death, who can check a box on the administrative panel of the certificate known as the obstacle médico-légal, or medicolegal objection. Checking that box halts all funerary arrangements and alerts the prosecutor, who then decides whether to refer the death to a local medicolegal institute. This structure introduces two extra layers of discretion compared with the American system, and therefore more opportunities for bias and error, since a non-specialist physician must decide on the spot whether a death warrants investigation.

Until 2017, the instructions for that checkbox, printed on the back of the paper certificate, referred only to suicide or suspicious death likely arising from a violation of the law. The revised certificate listed specific types of deaths that should trigger the notice, moving the French document closer to the highly prescriptive categorization used in the United States. Other changes targeted the supplementary information section of the medical panel: questions about the location of a violent death and about whether a death was pregnancy-related became multiple choice rather than open-ended, a question about sudden death and one about the apparent circumstances of death were added, and the question about whether an autopsy had been completed was replaced by one about whether an investigation into the cause of death had been requested. The revised certificate was piloted in several jurisdictions in 2017 and deployed nationwide in 2018, although the older version remained in use alongside it.

To measure the effect, the researchers drew on the CépiDC database, the nationwide compilation of all deaths in France maintained by INSERM, selecting the years 2016 through 2019 to balance pre- and post-reform certificates. They deliberately stopped before 2020 to exclude Covid-19 deaths. Two hypotheses were tested with logistic regression models, controlling for the sex and age of the deceased and for the type of certificate, whether adult or neonatal and paper or electronic. The first hypothesis was that medicolegal investigations would increase after the change. The second was that the precision of ICD-10 cause-of-death codes would improve. Precision was operationalized by classifying codes as vague or specific at the higher-order level, with all codes labeled other or non-specified counted as vague.

The results supported both hypotheses. Deaths certified on the 2017 version were more than twice as likely to be investigated by medicolegal professionals, with an odds ratio of 2.350. Electronic certificates were associated with an even larger increase in investigations, an odds ratio of 2.570, regardless of the certificate version, and neonatal deaths were close to ninety percent more likely to be investigated than adult deaths, reflecting the routine use of autopsies when infant deaths are difficult to explain. Women’s deaths were less likely to be investigated than men’s, and the likelihood of investigation declined with the age of the deceased, patterns the authors attribute to the fact that medicolegal investigations focus on violent and unexplained deaths, which women and the elderly are less likely to experience.

The second model showed that deaths certified on the 2017 version were almost ten percent more likely to carry precise ICD-10 cause-of-death codes, an odds ratio of 1.076. The authors argue that this finding, though less dramatic than the doubling of investigations, may be substantively more significant, because medicolegal investigations remained very rare even after the reform, whereas the improvement in coding applied across the full population of more than two and a half million deaths. Notably, the information on apparent circumstances of death, roughly equivalent to the American manner-of-death classification, was missing in 99.91 percent of deaths on the pre-2017 certificates but only 1.99 percent on the post-2017 certificates, simply because the new version included explicit checkboxes for those categories.

Some results complicated the picture. Neonatal certificates showed lower-quality cause-of-death coding than adult certificates, which the authors attribute to the wide proportion of vague codes within the ICD-10 perinatal categories and to the difficulty of explaining infant deaths when the child has no medical history. More surprisingly, electronic certificates were more likely than paper ones to be coded vaguely, the opposite of their effect on investigation rates. In 2024, automated batch-coding in France finalized only 63 percent of ICD-10 codes, with 83 percent of the remainder rejected for spelling errors, irrelevant information, or ambiguous acronyms. Because paper certificates offer no guardrails and thus require more manual coding, the authors suggest that this manual review may act as an additional layer of quality control that benefits paper certificates, a hypothesis that will need direct testing.

The researchers propose that the mechanism behind the improvement goes beyond simple instruction. More medicolegal investigations alone cannot plausibly explain an across-the-board improvement in cause-of-death coding, given how rare those investigations remain. They instead posit that the more detailed certificate forced physicians to slow down and think through each death more carefully, a process consistent with evidence from other contexts that slowing decision-making can improve judgment. Physicians filling out death certificates face real pressures: their attention is on the grieving family, funerary arrangements require certificates within tight windows, and non-specialists may neither grasp the public health importance of accurate mortality data nor be able to differentiate among competing causes of death. Embedding guidance directly in the form meets certifiers at the moment of decision.

The authors conclude that their natural experiment provides strong support for the hypothesis that more specific information on death certificates improves mortality statistics, a finding they consider translatable beyond France as long as policies are adapted to local administrative cultures. Two caveats frame the work: the study is a before-and-after comparison rather than a randomized trial, and the certificate reform overlapped with a simultaneous rise in electronic certification, which the models accounted for statistically but which operates in the same period. The next steps, the authors write, are to establish a dose-response relationship, determining how much guidance yields improvement and at what point returns diminish, so that cost-effective policy recommendations can be built on this evidence for health systems worldwide.

Subject of Research: Impact of the 2017 French death certificate reform on the accuracy of mortality statistics and medicolegal death investigations

Article Title: Implications of the 2017 change in the French death certificate for the accuracy of mortality statistics worldwide

Article References: Neuilly, M.-A., Balusson, F., & Bouvet, R. (2026). Implications of the 2017 change in the French death certificate for the accuracy of mortality statistics worldwide. International Journal of Legal Medicine. https://doi.org/10.1007/s00414-026-04039-x

Image Credits: AI Generated

DOI: 10.1007/s00414-026-04039-x

Keywords: death certificate, mortality statistics, France, medicolegal investigation, ICD-10, cause of death, epidemiology, natural experiment, forensic medicine, death certification, CépiDC, public health data