Beyond the average: why we need to start measuring variation in ages at death

Lifespan variation is a metric of mortality difference in age at death between individuals. With empirical examples from Germany, the USA, and Finland, we show how this variation is overlooked by monitoring metrics of average mortality levels, such as life expectancy. The latter captures the magnitude of survival gains; lifespan variation captures the equality in survival improvement. To gain a full picture of population health, we need to monitor both.