Created at the University of Minnesota in October 1997, the IPUMS consists of twenty-five high-precision samples of the American population drawn from thirteen federal censuses. Some of these samples have existed for years, and others were created specifically for this database. The twenty-five samples, which span the censuses of 1850 to 1990, collectively comprise our richest source of quantitative information on long-term changes in the American population. However, because different investigators created these samples at different times, they employed a wide variety of record layouts, coding schemes, and documentation. This has complicated efforts to use them to study change over time. The IPUMS assigns uniform codes across all the samples and brings relevant documentation into a coherent form to facilitate analysis of social and economic change.

IPUMS-International ( IPUMSⁱ) proposes to integrate individual level census samples for a large number of countries into a single databank. Our plan is, first, to standardize census microdata for selected countries from the 2000 round of censuses to the earliest available date (usually the 1960s or 1970s), and second, to distribute the integrated databank via the world wide web, CD-ROM or other means suitable for the delivery of massive datasets.

The success of such an ambitious undertaking will depend upon sustained collaboration with national census agencies, demographers, and statisticians in the countries selected. In many cases microdata samples already exist, but the project will fund, where necessary, the preservation of original data tapes on stable media as well as the extraction of new high-density samples consistent with necessary safeguards for confidentiality. The project will also purchase national technical assistance and census microdata needed for the project as well as host country professional expertise required for developing national standards for integrating census concepts and codes.

The IPUMS project has enjoyed almost a decade of support from federal funding agencies for integrating census microdata of the United States. The fruits of these labors may be seen at our web-site http://www.ipums.umn.edu, where researchers have access to data for 13 of the 15 national censuses conducted between 1850 and 1990.

Now, we propose to adapt this system, to internationalize IPUMS, by incorporating census microdata samples for the highest quality censuses with the longest time-spans from all the various world regions. We welcome your advice, assistance, and collaboration.