Spatial Partner Markets: Effective Competition, Scale, and Opportunity
Local partner markets differ not only in population size but in relative partner availability, the scale of opportunity, marriage timing, and population turnover. This paper develops a county-level framework for comparing these conditions across local partner markets. The empirical application focuses on unmarried women ages 25-34 and uses observed partner-age pairings to construct age-specific weights for the relevant unmarried male population. We model absolute opportunity separately, fitting a Michaelis-Menten diminishing-returns transformation to 192 scenarios that vary dating intensity, search horizon, fit, and first-date conversion. The resulting index also incorporates the share of women ages 35-39 who have never married and the inflow rate of adults ages 25-34. Among 320 counties with complete data, the District of Columbia ranks first and New York County second under the baseline specification, and rankings remain highly stable under alternative component weights. An endogenous mobility extension shows that favorable markets attract additional male participants, producing substantial adjustment while leaving the top composite rankings relatively stable over the parameter values considered. The framework is intended as a structural comparison of local partner-market conditions rather than a predictor of individual relationship outcomes.