How accurate are the United Nations world population projections

This paper investigates the accuracy of the UN world population forecasts of the age structure and crude birth and death rates in seven major regions of the world. Focus is on comparative accuracy across regions and over time utilizing data from 12 UN forecasts for Africa Asia Europe the former Soviet Union Latin America northern America and Oceania prepared between 1950 and 1985. Overall it is noted that the strength of these projections is that they contain detailed results for each country of the world computed on the basis of one consistent methodology and that they are updated frequently in the light of the most available data and methods. Compared with ex-post observed real trends the 12 sets of projections show a clear tendency over time toward greater accuracy. Part of the accuracy improvement is attributable to better data for base populations. In addition there is considerable regional heterogeneity in the accuracy of the UN projections. It is recommended however that the UN should include more than one variant for mortality in the projections due to difficulties with extrapolation and the considerable impact of exempting a variant on the results.