Since 1801, every ten years the nation has set aside one day for the census - a count of all people and households. It is the most complete source of information about the population that we have. The 2001 Census was held on Sunday 29 April 2001.
The planning, execution and evaluation of the decennial Census of Population and Housing is a vast and complex undertaking. It is often described as the largest peacetime operation carried out in the country. It is certainly the largest statistical exercise that we can contemplate, touching, as it does, every individual and household in the land.
Every effort is made to include everyone, and that is why the census is so important. It is the only survey which provides a detailed picture of the entire population, and is unique because it covers everyone at the same time and asks the same core questions everywhere. This makes it easy to compare different parts of the country.
The results are invaluable and allow central and local government, health authorities and many other organisations to target their resources more effectively and to plan housing, education, health and transport services for years to come. It is used as a reference base for many statistical series such as population estimates and projections and sample surveys.
In England and Wales, the census is planned and carried out by the Office for National Statistics. Elsewhere in the UK, responsibility lies with the National Records of Scotland and the Northern Ireland Statistics and Research Agency.
New for 2001
The 2001 Census built on the successes of the 1991 Census while introducing new innovations to meet the ever changing needs of users, changes in society, and the opportunities offered by rapidly developing technologies.
Postback of Census forms was introduced for the first time as the main means of collecting completed forms from households. This major change in the method of data collection allowed a significant reduction in the field force necessary to carry out the Census and helped to free up resources to focus on other areas and help to make 2001 the best Census yet.
To meet the needs of users for more accurate information, all responses to all of the questions were processed, and results were published for all of the topics, for 100 per cent of the population. In previous censuses, several of the traditionally expensive and hard-to-code questions were processed for only a 10 per cent sample of forms. Modern technology, however, enabled the processing of all forms.
With the introduction of the Census Access initiative, the bulk of the results from the Census - a vast amount of data indeed - was made available publicly, through electronic media and via the National Statistics website, free, in effect, at the point of delivery.
More information about many aspects of the Census can be found in the 10 2001 Census factsheets. A detailed account of the planning and evaluation of the 2001 Census is available in the 2001 Census General Report.
Census results - a rich source of information
The information from the Census forms was processed to produce a database from which results are drawn - information about identifiable individuals is never released. They are presented either as simple counts, such as the number of young children, or as figures which relate one topic to another, such as the number of children in one parent families. The linking of topics is one of the most valuable features of a Census.
Most figures are about the people who live in an area, but others are about people who work in an area or about migrants from an area.
For 2001, the results released accross all forms or statistical output numbered over two billion individual counts.
The results represent 100 per cent of the population as it was on Census day 2001. But they are estimates. This is because some people were missed by the Census and not everyone answered every question. The missing information had to be imputed on the basis of evidence from people and households of similar types.
The outcome is generally accurate, but does vary by area and topic. Too much should not be deduced from very small numbers, or where local knowledge indicates that there may have been significant change since 2001, although the characteristics of areas tend to persist even when people move in and out.
Full descriptions of all of the results from the 2001 Census - including details about were to find them online or how to order them in print or on CDs or DVDs can be found in the Data and product catalogue.