Human geographers are interested in how people live and how they interact with the environment in which they live. Much of the data that human geographers use comes from censuses, surveys, and statistical reports of one sort or another. A census is a periodic count of the population usually conducted by a national government. Censuses have been around for millennia but the first decennial (every decade) census was conducted in the United States in 1790. The United States has conducted a census every ten years since then in order to determine the distribution of population to insure equality of voting in accord with the Constitution 1.
Most censuses concentrate on counting noses--finding out how many people live in a place. However, they also collect information on a wide variety of other characteristics of population. Most censuses record data on age, gender, and marital/family status (is the head of household married, divorced, single; how many people live in a residence and what their relationship to each other is). The United States census also collects information on quality of housing, employment status and occupation as well as race and/or ethnic affiliation. In the United States, the population census is now conducted by mail, and census takers will visit only households from which a mail questionnaire is not returned. Other information may be collected via a random sample that is designed to obtain data from a representative group rather than the entire population of the United States.
Another important advantage with respect to censuses is accuracy. The United States, which has the longest continuous record of census taking and which uses very sophisticated techniques to insure the accuracy of its census, admits to a five percent error rate. To make matters worse, the error rate varies spatially and with respect to ethnic minorities.............
