The ONS is too optimistic about the UK’s demographic prospects
January 31, 2025
The Office for National Statistics’ recently-published national population projections expect continued population growth for the United Kingdom at a relatively strong pace until 2047. This forecast might come as something of a surprise given the constant drumbeat of news about falling fertility rates in the UK and abroad. As this brief review of British population dynamics will suggest, the ONS’ forecast includes several unfounded assumptions which lead to considerable excess optimism about the future of British population growth.
Projection vs. Forecasting: a distinction without difference
Before addressing the data the ONS provides, it should be noted that the ONS adopts an unreasonable distinction: that “projections” are different from “forecasts.” The ONS places a warning on their published document saying, “National population projections are not forecasts and do not attempt to predict potential changes in international migration. Migration assumptions do not directly account for recent and future policy or economic changes. Demographic assumptions for future fertility, mortality and migration are based on observed demographic trends.” This disclaimer is strange, since “projection” is simply, etymologically, derived from the Latin “to launch forward,” while “forecast” is simply, etymologically, derived from the Old High German “to launch forward.” They are literally synonyms, and in fact identically derived, it’s just that Alfred the Great made forecasts, while William the Conqueror made projections.
