How well mortality can be forecast, and by whom

Official projections of life expectancy have been wrong in the same direction for decades — too low, until the 2010s, when in several countries they became too high as improvement stalled — and the question is whether anyone forecasts mortality better than the offices, and how one would know. The models are well described: extrapolative ones, cause-specific ones, expert-judgement ones, ensembles, and now machine-learning approaches that claim more from the same data. Their track records are less well described, because forecasts are seldom scored against outturns in public and the horizon that matters is decades. What the evidence does show is that the errors come mostly from turning points — the stall, the pandemic — that no extrapolative model anticipates, and that cause-specific and expert-judgement models fared no better at them. Whether the newer methods change that is exactly the kind of claim that will take years to test. The site's projection-versus-outturn pages are the evidence for this driver as they accumulate.

Status

contested

Direction

mixed

Would change our view

A published comparison scoring competing forecasts against outturns over a decade or more; or a method that demonstrably anticipated a turning point rather than fitting it afterwards.

Trackers

Gaps

Public forecast archives in most countries; any scoring of the actuarial and insurance models, which are private; forecasts for ages over 90, where the data are thin and the stakes highest.