An expert-based framework for probabilistic national population projections: The example of Austria

The traditional method of dealing with uncertainty in population projections through high and low variants is unsatisfactory because it remains unclear what range of uncertainty these alternative paths are assumed to cover. The probabilistic approaches have not yet found their way into official population projections. This paper proposes an expert-based probabilistic approach that seems to meet important criteria for successful application to national and international projections: (1) it provides significant advantages over current practice; (2) it presents an evolution of current practice rather than a discontinuity; (3) it is scientifically sound; and (4) it is applicable to all countries. In a recent Nature article (Lutz et al., 1997) this method was applied to 13 world regions. This paper discusses the applicability to national projections by directly taking the alternative assumptions defined by the Austrian Statistical Office. Sensitivity analyses that resolve some methodological questions about the approach are also presented