The census is a statistical exercise undertaken to inform the government, counting and recording facts about the population. You could say that the first large scale census taken in modern history was Domesday and there have been others over the years, such as Muster rolls, taken to see what able-bodied men and weapons were available for war.
A census, as we understand it now has been carried out every decade since 1801. The only exception was 1941 when other things seemed more important. It is not intended for family historians to use, but as a government exercise in finding out statistics about the population, to enable them to make informed decisions on a wide variety of topics including housing, transport and food, and to identify the strengths and weaknesses in the economic structure of the country.
From 1801-1831, purely statistical data was collected with no usable genealogical material, however the 1841 census introduced records with some personal information for the first time. The usefulness of the 1841 census is limited to family historians because it didn't accurately record people's ages, or where they were born, only noting if they were born in the same county or not.
The amount of information collected was extended in 1851 and from 1851 to 1901 there are only minor changes to the information recorded on the census form. The principal information you can expect to find is:
In addition to the above, the 1911 Census was the first to include the number of years a couple had been married and how many children had been born to that marriage.
Many people don't realise that the census page images we see are actually transcripts of the household census forms, the details being copied into the books by enumerators. This provides several opportunities for mistakes to occur, firstly as they tried to decipher the writing on the household forms, which were later destroyed. Illiterate or barely literate ancestors may not have understood the form or even known with any accuracy the answer to the questions. They may have been suspicious of this government prying into their affairs and been less than honest in their answers. Just as today, a certain percentage manage to avoid being included, either deliberately or accidentally. With the possibility of errors and misinformation creeping in from the very outset, you should always use your own judgment when assessing the information from the census. It may be completely accurate, but you will often find discrepancies.
Because of these problems, TheGenealogist has come up with some unique tools to help you find your relatives; such as the family forename search tool, which allows you to search for a group of people by forename only or the house & street search, allowing you to see exactly who is living at a particular address and the keyword master search, which allows you to search for a list of key words; such as name, year/place of birth, occupation and area, etc.
The biggest problem for the family historian is actually finding the entries they need amongst this vast collection of data. Unless your ancestors never moved more than a mile from their origins, some sort of finding aid is required.
At first the only help available was an index to places, to help you locate the relevant section to manually search page by page, and for larger towns and cities a street index. Family history societies then started to index their areas and make some name indexes available. These didn't make a very large impression though and most of the census remained unindexed until the joint project to transcribe and index the 1881 census took place and showed what could be done. The upsurge in the use of home computers and the internet have brought a complete new set of tools to the aid of the family historian, and an ever growing demand for more information to become accessible online.
British Data Archive have made the census page images available on CD, for everyone to use on their own home computers at any time. This itself was a great improvement, as only a couple of years ago you would probably have had to travel the country to get only a couple of hours access. Having produced the images for everyone to use, the next logical step was to provide those images with the indexing necessary to make them easy to use, and with this aim in mind, S&N set up The Genealogist indexing and transcription project