Linked Historical Censuses
The historical microdata permit linking of individuals between census years for longitudinal analysis. Currently, seven U.S. census samples are linked to the full-count 1880 dataset, and the Norway 1865, 1875, and 1900 censuses are linked to each other. The U.S. data include separate samples that link men, women, and couples between pairs of years. The Norway data link men and couples. Each linked sample contains data on all linked individuals and records for other members of the linked person's household from both years. Currently, the linked datasets contain information on nearly 600,000 people at two points in time (180,000 in the U.S. and 400,000 in Norway).
Procedures for linking individuals in the different North Atlantic countries are similar. The basic methods were developed by linking the U.S. complete count 1880 census to the sample datasets from 1850 to 1930. These methods were then applied to other countries, adapting the approach to address differences in the information available for linking. The primary goal in constructing these longitudinal databases has been to minimize selection bias and maximize representativeness of the linked cases. This approach requires a very conservative linking strategy; consequently, the samples include only a fraction of the total population in any census year.
The detailed linking procedure discusses the method for creating links for the U.S. and the modifications necessary to create linked data for Norway.