Non-American census data in machine readable form

Most of the countries of the world have conducted a census of population during the last ten years, and almost every country hasf plans to conduct such a census at some time during the next decade. The two exceptions are Iceland and Denmark, which are considering the use of Population Registers as a substitute for population censuses. Census data are almost always processed with the aid of a computer. As a byproduct of this processing, all central statistics offices have basic record tapes (individual records for every enumerated household and/or person). Summary tables-those which are subsequently published, as well as others-are frequently also available in machine-readable form. In addition, public-use sample tapes (records from a sample of the enumerated households and/or individuals, usually stripped of identifying information) may also exist. Census data have long been used by demographers and other social science researchers to investigate a diverse assortment of questions concerning fertility, migration, family composition, the distribution of certain social and economic variables in specified populations, etc. Since this type of research usually involves the use of computers, the availability of census data already in machinereadable form would not only save time and money but broaden the number, and range of complexity, of the research problems open to investigation. However, until recently, little information has been available concerning the existence of machinereadable census data or the willingness of central statistical offices to release these rinfn for nrc,-nror niurnn<epe In November 1973, an initial inquiry concerning national population and housing censuses was sent by the author to 160 central statistics offices. That inquiry covered such items as dates of last and next censuses, the use of computers for internal processing, and the release of data in machine-readable form for use by researchers. Seventy-five responses were received to this inquiry, and these responses were presented and discussed in an article in Population Index in October 1974. In order to update that report and gather additional information, in April 1975 reprints of that article, together with a covering letter and a new questionnaire, were mailed out to a slightly expanded list of central statistics offices (copies of the letter and the questionnaire are available from the author). Efforts were made to make both the letter and the questionnaire as simple and straightforward as possible in order to encourage response and avoid ambiquity. It was hoped that the inclusion of the previous report would also serve to encourage response, particularly from those countries who had not responded to the earlier inquiry. Since the out-ofpocket costs of this second mailing were supported by the International Statistics Program Center of the U.S. Bureau of the Census, the questionnaire was modified to meet the needs of that office by adding questions on post-enumeration surveys and on publication of national and regional data, by requesting a printed list of tables, and by introducing more detail to the computer questions. As of this writing, there have been 93 responses to the second mailing. Many of these were from countries which had responded to the first mailing. Taken to-