I.

Introduction

Census, term usually referring to an official count by a national government of its country’s population. A population census determines the size of a country’s population and the characteristics of its people, such as their age, sex, ethnic background, marital status, and income. National governments also conduct other types of censuses, particularly of economic activity. An economic census collects information on the number and characteristics of farms, factories, mines, or businesses.

Most countries of the world conduct population censuses at regular intervals. By comparing the results of successive censuses, analysts can see whether the population is growing, stable, or declining, both in the country as a whole and in particular geographic regions. They can also identify general trends in the characteristics of the population. Because censuses aim to count the entire population of a country, they are very expensive and elaborate administrative operations and thus are conducted relatively infrequently. The United States conducts a population census every ten years (a decennial census), and Canada conducts one every five years (a quinquennial census). Economic censuses are generally conducted on a different schedule from the population census.

Censuses of population usually try to count everyone in the country as of a fixed date, often known as Census Day. Generally, governments collect the information by sending a questionnaire in the mail or a census taker to every household or residential address in the country. The recipients are instructed to complete the questionnaire and send it back to the government, which processes the answers. Trained interviewers visit households that do not respond to the questionnaire and individuals without mail service, such as the homeless or those living in remote areas.