This epidemiologic investigation will establish area-based measures of socioeconomic position appropriate for US public health surveillance systems and health research. To create these measures, we propose a cross-sectional study involving two US states, Massachusetts (MA) and Rhode Island (RI), using public health surveillance data from the mid-1980s to mid-1990s in conjunction with 1990 census tract, census block-group, and zip code socioeconomic data. We will: (1) geocode public health surveillance data bases containing individuals' residential addresses by appending codes for each address's census tract, block-group, and zip code; (2) create different area-based socioeconomic measures that we will apply to each geographic unit (census tract, block-group, zip code), following and extending approaches used in extant public health and social science literature; (3) link each geocoded record to the relevant census tract, block-group, and zipcode area-based socioeconomic measures; (4) investigate the comparability of the area-based socioeconomic measures, by state, with regard to both socioeconomic ranking of geographic units (centus tract, block-group, zip code) and sensitivity and specificity in predicting available individual-level socioeconomic data obtained in three public health data bases (birth and death certificates and the RI Health Interview Survey); (5) compare quantification of associations of the area-based socioeconomic measures with health outcomes, within and across geographic units (census tract, block-group, zip code), by state, for outcomes expected to exhibit socioeconomic gradients in health: birth rate, birth weight, gestational age, infant mortality, adult mortality (all-cause and cause-specific), cancer incidence, sexually transmitted diseases, tuberculosis domestic violence, gun shot and stab wounds, and childhood lead screening, as well as compare results to gradients in health detected with individual-level socioeconomic data, using the birth and death certificate and RI Health Interview Survey data, and (6) select the most valid, powerful, and easily understood area-based socioeconomic measure(s) and prepare a monograph explaining our methodology, to facilitate use of area-based socioeconomic measures by health agencies and researchers. In doing so, our project incorporates socioeconomic data, a powerful determinant of population health, disease, and well-being, into routinely collected public health data and greatly augments capacity to: (a) monitor socioeconomic inequalities in health in the United States, (b) analyze the contribution of socioeconomic inequality to racial/ethnic inequalities in health, and (c) guide allocation of resources and interventions to attain social equity in health.