been the online availability of 1980 and 1990 1 percent PUMS data. The Consortium for International Earth Science Information Network (CIESIN), located in Saginaw, Michigan maintains both the 1980 and 1990 PUMS data on workstations. Users can dial the telephone number, on one of several lines, for the Saginaw workstations, access either the 1980 or 1990 data, request specific tabulations or descriptive statistics, and receive the requested data back in typically 5-8 seconds.

CIESIN's computers are online continuously and allow users to obtain instantaneously tabulations for any population of interest. For example, a user might be interested in the labor-force status for Hispanic and black men and women, aged 18-24 years, who completed 4 years of high school and who live in a specific metropolitan area or a specific state. One might want to compare their unemployment rates to the national average or to compare the 1990 rates to 1980. CIESIN's workstation computer and online software allow researchers to obtain such tabulation almost instantly.

The widespread and continuous use of census data on the CIESIN's computer is evidence that there is strong demand for even greater accessibility to census data. There are now more researchers using the CIESIN census data in a single day than used the 1960 PUMS data in the 1960s over the entire decade. The future trends seem to be the development of increasingly easier access to public-use census samples, probably with improved online systems and greater user-friendly CD-ROMs, for the 2000 census.

NOTES

1  

PUMS data support a great deal of multivariate analysis that can be tailored to specific research questions. Although the summary tape files with aggregated data may limit the particular cross-tabulations available, aggregated data have often been used for studies of residential settlement, especially residential segregation, based on the spatial analysis of particular social groups.

2  

Individual microdata were not collected from the slave population in the 1850 census.

REFERENCES

Rockwell, R.C., and E.W. Austin 1991 1990 U.S. Census Data Project. Proposal submitted to the National Science Foundation. Inter-university Consortium for Political and Social Research, Ann Arbor, Mich.

Ruggles, S. 1993 Historical Census Projects: Integrated Public Use Microdata Series. Social History Research Laboratory, University of Minnesota, Minneapolis.



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