A note on the compression of mortality

The rapid increase in human longevity has raised important questions about what implications this development may have for the variability of age at death. Earlier studies have reported evidence of a historical trend towards mortality compression. However, the period life table model, commonly used to address mortality compression, produces an artificially compressed picture of mortality as a built-in feature of the model. We base our study on an examination of the durations of exposure, in years of age, of birth cohorts and period life tables to selected levels of mortality observed at old age. We also address the problem in a more conventional fashion, by examining the distribution of ages at death above and below the mode. Overall, mortality has been decompressing since the 1960s. This finding contradicts most previously reported results. The decompression of old-age mortality may further indicate good prospects for ever-decreasing mortality. In the future, deaths may not be concentrated within a narrow age interval, but will instead become more dispersed, though at ever later ages on average.