Census microdata are the individual responses to census questionnaires
recorded in computerized form as numeric or alphabetic codes. The data include
demographic characteristics such as age, sex, marital status, relationship to head of
household, migration, education, and occupation among other individual-level variables.
They also include information on household characteristics such as urban/rural living,
home ownership, and access to utilities like electricity and water supply, and number of
rooms in the household. Over the past half century most of the major statistical
agencies have prepared census microdata files for analysis by staff and, in many cases,
by external researchers. With ever-expanding access to computers, analysis of large
census microdata files is now possible for ordinary researchers, and even students, as
this article will later demonstrate.