Population estimates; backseries methodology for 1992-2000

In each decade, population estimates are rebased using data from the most recent census. However, this would lead to a step change in the population estimates series. To avoid this discontinuity the backseries for 1992 to 2000, was revised to bring it into line with the 2001 Census. This article discusses the methodology used to produce the final revised backseries for 1992 to 2000 published by ONS in October 2004. The final estimates were produced after a long period of research into the best methodology to use. Traditionally, the backseries have been revised using an interim simple period method, followed by a final simple cohort method. The approach taken following the 2001 Census was much more comprehensive. This article outlines this approach, summarises the range of methods available and describes in detail the final method selected.