Measuring Exclusionary Zoning in the Suburbs

Robert C. Ellickson
Yale Law School

When state law permits, cities and suburbs tend to adopt exclusionary zoning policies designed to keep out the less affluent. Urban scholars have long lamented the dearth of metrics for measuring the exclusionary tendencies of the policies of specific localities. The Wharton Residential Land Use Regulatory Index, published in 2008, is currently the most cited. It has many virtues, but it is hardly above criticism. The questionnaire that the authors of the Wharton Index circulated to local governments drew a 38-percent response rate.

This article offers five metrics for measuring the exclusionary tendencies of a suburb’s zoning policies, as well as an aggregate metric that combines the five. Each metric assumes that the contents of the local government’s published zoning map and ordinance sincerely express its policy intentions. The article applies the metrics to 37 suburbs and, in some instances, to four additional localities in three particular U.S. metropolitan areas. The three are Silicon Valley, the region with the most astronomic housing prices in the United States; Greater New Haven, Connecticut, the Frostbelt representative; and the northwestern sector of Greater Austin, Texas, one of the fastest growing metropolitan areas in the United States. Austin suburbs are found to have, as most would predict, less large-lot zoning, more small-lot zoning, and fewer restrictions on the construction of multifamily housing. The various metrics promise to help reveal differences in land-use policies across space and time.