We apply counterfactual population projections to 11 European countries with long-run demographic data series and undertake detailed analysis for three countries, England & Wales, France and Sweden, with base years covering the extended period 1850 to the present to estimate the performance of counterfactual population projections to estimate the contributions of fertility and mortality to population ageing.

We conclude that there are a number of substantive and technical weaknesses in the counterfactual projections approach, in particular the results are very sensitive to the choice of base year. The level of fertility in the base year appears to be the main factor that determines whether the counterfactual projection approach suggests that fertility or mortality id the main driver of population ageing.