CAN WE REACH CONSENSUS ON CENSUS ADJUSTMENT

Attempting a complete headcount is an imperfect method for carrying ou t a census, as is modifying an attempted headcount with sample-based a djustments. It is a mistake to assume that one approach enjoys a scien tific presumption over the other. There are important details availabl e from evaluation studies of the 1990 decennial census that reflect up on the accuracy of adjusted and unadjusted census figures. Decisions a bout adjustment might therefore be based on comparing the accuracy of alternative census-taking strategies at some level of aggregation of t he population. In any such comparison, the choices of an appropriate l evel of aggregation, the factors defining the aggregation, and appropr iate loss criteria are important issues to decide in advance. After pr oviding context for decisions about census-taking strategy, we comment on the recent literature on census adjustment, including the papers b y Freedman and Wachter and by Breiman contained in this issue; we also discuss the Census Bureau's plans for the year 2000. We conclude that the 1990 approach to summarizing the accuracy of an adjusted census c an be improved upon, but that many of the criticisms of census adjustm ent do not reflect a balanced decision-making perspective. We also con clude that the Census Bureau is pursuing constructive research in eval uating a ''one-number census,'' and we suggest that statisticians have a role to play in avoiding the costly legal battles that have plagued recent censuses by assisting in the process of deciding on a design f or the 2000 census.