Forecasting U.K. Population Mortality Allowing for Age, Period and Cohort Effects

Abstract

ABSTRACTThe mortality data (registered deaths and population size) over the years 1961–2007 for the population of England and Wales and for Scotland were obtained from the Office for National Statistics (ONS) and from the Scottish Registrar General. This paper addresses the following questions:(i) Is there statistical evidence for a cohort effect (i.e. a generation effect separate from the period effect) being present in the data?(ii) Do both males and females exhibit similar cohort (generation) effects?(iii) Are period effects (i.e. the improvement in mortality with time) more significant than cohort effects?(iv) How should one allow, in forecasts of population mortality, for age, period and cohort effects?(v) Is it sensible to combine male and female mortality experience to determine the period effect and the cohort effect?(vi) How do the forecasts for the expectation of life at birth, using the Extended-Lee–Carter-Combined (ELCC) model (described in the paper) differ from the (2008 based) Office of National Statistics (ONS) forecasts of the expectation of life at birth?