of reliable information for matching the separate lists (e.g., date of birth). This latter concern is especially important for triple-systems estimation, where the amount of matching is tripled in comparison to dual-systems estimation.
The second possibility is reverse record check, the primary method used by Statistics Canada in evaluating the coverage of the Canadian census (Gosselin, 1980). In this technique, samples of births, immigrants, those counted in the most recent census, and those missed in the most recent census (which is roughly provided by the previous implementation of this program) are each traced to their current address to arrive at a target count for each area to compare against the census counts. Since the Canadian census is taken every 5 years, tracing addresses forward in time requires finding people after a lag of only 5 years. On the other hand, for the United States census, tracing would have to extend over a lag of 10 years. This crucial difference in the application of this technique to the United States census was tested by the Census Bureau in 1984 in the Forward Trace Study (Hogan, 1983), in which it was discovered that tracing over 10 years was not feasible. However, administrative lists are of higher quality than in 1984, and it may be that reverse record check should be reevaluated as a possibility in the United States census.