A central goal of IPUMS-International is to create an inventory of surviving census microdata and documentation. We are collecting enumerator instructions, census forms, codebooks, studies of data quality, and any other ancillary documentation we can locate for all countries that will allow us access to this information. Wherever feasible, we have obtained copies of microdata as well as metadata.

The microdata inventory meets several needs. First, it constitutes an important resource in its own right for researchers and data archivists. Second, the inventory underpins the design of the IPUMS-International database, allowing us to design the system to accommodate future expansion by taking into account the range of variation in census content and concepts around the world. Third, the microdata inventory will help us identify additional census and survey resources that should be preserved.

The first edition of our inventory of machine-readable census microdata was published in the Handbook of International Historical Microdata for Population Research edited by Patricia Kelly Hall, Robert McCaa, and Gunnar Thorvaldsen (Minnesota Population Center: Minneapolis, 2000). This publication received the 2001 award for "Best Book" by the American Association for History and Computing.

An updated microdata inventory can be accessed here.

Of some 230 extant census microdatasets currently inventoried, almost one hundred are being preserved under the direct auspices of the IPUMS-International initiative. Our preservation efforts extend to all machine-readable datasets that are in danger due to technological obsolescence, even where there is little likelihood that the data will be made available to researchers.

Complete and comprehensive metadata are essential for the use and interpretation of census microdata. The Minnesota Population Center took an important step toward the preservation of census metadata when it acquired the Historical Archive of census documentation (approximately 150 linear feet of printed materials) from the United Nations Statistics Division in 2000. Our enumeration form scanning project has electronically scanned much of this material, using procedures adapted from those used by the Inter-university Consortium for Political and Social Research, to create documents in Adobe’s PDF format. Products from this acquisition are World Census Questionnaires: First Edition.