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The Facing Up to Uncertain Life Expectancy: The Longevity Fan Charts

Kevin Dowd, David Blake and A.J.G Cairns

This article uses longevity fan charts to represent the uncertainty in projections of
future life expectancy. These fan charts are based on a mortality model calibrated
on mortality data for English and Welsh males. The fan charts indicate strong
upward sloping trends in future life expectancy. Their widths indicate the extent of
uncertainty in these projections, and this uncertainty increases as the forecast
horizon lengthens. Allowing for uncertainty in the parameter values of the model adds
further to uncertainty in life expectancy. The article also illustrates how longevity fan
charts can be used to stress-test longevity outcomes.