A census is a collection of information on a group of people. Census information is usually collected in order to gain some data that is relevant to the population as a whole. Information is ideally collected from every household, although this is not always possible. Census information is collected by specially trained staff.
The main reason for a census is to gain a figure on the growing population. In general, a census is taken once every ten years. Some countries and regions go through significant changes in just a single decade. Population growth can vary greatly and may not be due solely to the birth rate. Social and economic factors also play a part in population numbers.
Census information is a national concern and should involve everyone in the country where it is held. There is usually a specified census date, and all information should be collected by then. Undertaking a census is a huge task, and there are many issues to be considered. The first issue is to determine what information is needed.
To collect census information, areas of the county are divided into enumeration districts. A census interviewer is assigned to each individual district. The interviewer is trained to fully understand each and every aspect of the information needed. During the month before the census, the interviewer begins preliminary enumerations. The interviewer will visit each building in his or her assigned district and quickly and accurately complete the census questionnaires.
Once the questionnaires have been completed, they are taken to a main census office to be checked and coded. The census information is then ready to be input into computers that can generate the required statistics. The quality of the statistics given depends on the amount of questionnaires that have been taken, as well as on the quality of the questionnaires. If the answers have been given honestly and without bias, then the statistics will reflect this.
Many people are often worried that census information can be used for other purposes. The information on the questionnaires is completely confidential. In the US, it is protected by the Statistics Act. No one involved in the census is permitted to give out any information. All census staff take an oath of secrecy and will not divulge the information held under any circumstances.