Census 2001 (Hansard, 30 October 2002)

§ Ruth Kelly

The information requested falls within the responsibility of the National Statistician. I have asked him to reply.

Letter from Len Cook to Mr. Gordon Prentice, dated 30 October 2002: As National Statistician and Registrar General for England and Wales I have been asked to reply to your recent question to the Chancellor of the Exchequer asking what assessment has been made of the accuracy of the 2001 Census. (77401) Census 2001 results are the first to represent the entire population. This was achieved through a new strategy known as the 'One Number Census'. One of the key elements was an independent follow-up survey. The Census Coverage Survey (CCS), as it is known, involved an intensive face-to-face survey of a sample of over 16,000 postcodes containing 320,000 households covering every local authority in England and Wales. By combining the results of the Census and the CCS, it was possible in 2001 to estimate the total resident population-the 'one number' - to a high level of precision. plus or minus 0.2 per cent., and to provide information on the characteristics of those persons missed by the Census. 862W Thus in 2001, the Census results represent 100 per cent. of the population. Census response, that is the proportion of people returning a form in England and Wales, was 94 per cent. The 6% of people estimated to have been missed by the Census have been added to the counts using a statistical process that was subject to extensive consultation, and based on the results of the CCS. I am confident that the approach we have taken to the 2001 Census provides the most accurate estimates of the population both nationally and for each of the 376 local authorities in England and Wales. No census ever gets responses from 100 per cent. of the population. The 2001 Census was designed from the outset to take full account of this to provide what users of statistics really want—figures representing everyone. In addition, the 2001 Census has undergone rigorous testing and quality checking throughout both the fieldwork and processing. Census tests were carried out in 1997 and 1999 and a survey designed to measure the accuracy of response to each question has been completed. Furthermore, a comprehensive set of verification and validation checks were built in to the processing of the data, and data quality played a key role in all aspects of processing the forms. All information on accuracy will be contained in a Census Quality report to be published in 2003. Information published so far about the accuracy of the Census is available on the National Statistics website at www. statistics. gov. uk.