What Planners Know

Problem, research strategy, and findings: To understand how local land use regulation affects housing development, many researchers have surveyed planners about their jurisdictions’ policies and practices. But researchers have not systematically assessed whether such surveys yield valid and reliable information. We provide such an assessment by analyzing nine surveys conducted between 1988 and 2018 in California, the state where concern about underproduction of housing has been most pronounced. Each survey attempted to inventory local land use regulations, and some surveys also queried planners about their subjective perceptions regarding constraints on housing development. We find strikingly different responses to similar inventory questions about specific land use regulations in two surveys conducted months apart in the same municipalities, casting doubt on the reliability of such measures. Regression analysis reveals that subjective survey measures concerning land supply and density restrictions predict subsequent housing production, unlike counts of purportedly objective measures. Comparing survey data with recently developed GIS data indicates planners identify land supply as a significant constraint on residential development in municipalities where a relatively low proportion of land is vacant or in agricultural use, while identifying regulatory restrictions as a constraint in jurisdictions with little land zoned for multifamily use.Takeaway for practice: Asking planners to identify which land use regulations their localities have “on the books” does not provide a clear measure of regulatory stringency. By contrast, municipal planners’ subjective perceptions may capture otherwise unmeasurable characteristics of local land use policy. Although planners’ subjective perceptions can provide a relatively holistic measure of local land use policy, they have limited value for policy prescription. Given the problems of survey-based measures, state and federal government agencies should collect, harmonize, and distribute data concerning local land use regulation, including zoning district designations. Fair housing assessment tools and regional planning processes could facilitate these activities.