How Many of us are there and where are We? A Simple Independent Validation of the 2001 Census and its Revisions

In this paper I present two simple checks on the geographical validity of the UK 2001 Census and on the revisions of population estimates which have been made after its release. The huge difficulties inherent in estimating simply the population's human geography, let alone its characteristics, are discussed, and I conclude that current estimates may now be as close as they will ever be to a true estimate of the population—but are in places very unreliable. The slightly haphazard way in which the United Kingdom finally arrived at its 2001 population estimates, by the latter half of 2004, is commented upon. The UK population was reported to have passed the 60 million mark twice: once in 2001 and then again in 2004. With such national uncertainty, confidence in local population estimates is obviously low. This uncertainty also raises issues over the practicality of recent attempts to estimate the size of the supposed illegal population living in the United Kingdom, even before any moral objections are raised over attempts to count those whose existence here is deemed to be illegal. An uncertainty principle is introduced whereby, as the population becomes more mobile, observation becomes ever more unreliable. I end the paper by discussing the implications of changing human geography for its enumeration with a suggestion for a revision to the census form in 2011 to allow us to count better in the future. I conclude that comparisons with administrative records are not a panacea for estimating the population of the United Kingdom. Instead, further checks within the census process are suggested for the future.