Is there a cap on longevity? A statistical review

TL;DR

This paper reviews statistical methods for analyzing extreme human lifespans, suggesting no definitive upper limit exists and that remaining life after age 109 follows an exponential distribution.

Contribution

It clarifies correct statistical approaches for longevity data and reanalyzes existing data to assess the existence of a lifespan limit.

Findings

Remaining life after age 109 is exponentially distributed.

Upper lifespan limit, if any, is beyond current record ages.

95% confidence lower limit for maximum lifespan is around 130 years.

Abstract

There is sustained and widespread interest in understanding the limit, if any, to the human lifespan. Apart from its intrinsic and biological interest, changes in survival in old age have implications for the sustainability of social security systems. A central question is whether the endpoint of the underlying lifetime distribution is finite. Recent analyses of data on the oldest human lifetimes have led to competing claims about survival and to some controversy, due in part to incorrect statistical analysis. This paper discusses the particularities of such data, outlines correct ways of handling them and presents suitable models and methods for their analysis. We provide a critical assessment of some earlier work and illustrate the ideas through reanalysis of semi-supercentenarian lifetime data. Our analysis suggests that remaining life-length after age 109 is exponentially distributed, and that any upper limit lies well beyond the highest lifetime yet reliably recorded. Lower limits to 95% confidence intervals for the human lifespan are around 130 years, and point estimates typically indicate no upper limit at all.