DISCUSSION PAPER PI-0801
Mortality Density Forecasts: An Analysis of Six Stochastic Mortality Models
Andrew J.G. Cairns, David Blake, Kevin Dowd, Guy D. Coughlan, David Epstein and Marwa Khalaf-Allah
This paper develops a framework for developing forecasts of future mortality
rates. We discuss the
suitability of six stochastic mortality models for forecasting future mortality
and estimating the density of mortality rates at different ages. In particular,
the models are assessed individually with reference to the following qualitative
criteria that focus on the plausibility of their forecasts: biological reasonableness;
the plausibility of predicted levels of uncertainty in forecasts at different
ages; and the robustness of the forecasts relative to the sample period used
to fit the model. An important, though unsurprising, conclusion is that a
good fit to historical data does not guarantee sensible forecasts. We also
discuss the issue of model risk, common to many modelling situations in demography
and elsewhere. We find that even for those models satisfying our qualitative
criteria, there are significant differences among central forecasts of mortality
rates at different ages and among the distributions surrounding those central
forecasts.
Key words:- Plausibility, Fan charts, Model risk, Forecasting, Model selection
criteria
