ASSESSING BETWEEN-BLOCK HETEROGENEITY WITHIN THE POST-STRATA OF THE 1990 POST-ENUMERATION SURVEY

The 1990 Post-Enumeration Survey (PES) stratified the population into 1,392 subpopulations called post-strata based on location, race, tenur e, sex and age, in the hope that these subpopulations were homogeneous in relation to factors affecting the Census coverage. Homogeneity is necessary to justify the use of the same adjustment factor for many, s ometimes quite small, subgroups of the post-strata. With block-level d ata from the PES for sites around Detroit and Texas, we are able to ex amine empirically the extent to which this hope was realized. Using va rious measures, we find that between-block variation in erroneous enum eration and gross omission rates is about the same magnitude as, and l argely in addition to, the corresponding between-post-stratum variatio n.