Scott Markley (Land Use Atlas, Inc.), Sara C. Bronin (George Washington University – Law School), and Matthew Harris (Land Use Atlas, Inc.) have posted It’s Time to Retire the Wharton Index on SSRN. Here is the abstract:
Empirical research on land use regulation has a credibility problem. For two decades, studies linking regulation to housing costs, residential segregation, and social mobility have primarily relied on an unreliable metric: the Wharton Residential Land Use Regulatory Index (WRLURI). Developed from surveys of local governments across the United States in 2005 and 2018, the Wharton Index claims to quantify the restrictiveness of regulation at the municipal and metropolitan level in a single number. Cited over 1,500 times in academic research and used widely in policy reports and government studies, its survey-based outcomes have never been fully scrutinized, nor have they been tested against actual land use regulations on the ground. In this paper, we audit the Wharton Index. We first disassemble its twelve subindices to clarify how they are made, finding that they have little to do with the content of any regulations at all. We then map its coverage, showing that its metropolitan-area-level scores rest on thin, unrepresentative slices of the regions they are used to rank. Finally, we assess the 2018 index against standardized zoning data from the National Zoning Atlas, measuring not just whether regulations exist but how much land they govern. The associations between WRLURI scores and actually existing restrictive zoning rules are essentially random, if not negative. These findings call for a full reassessment of the scholarship built from the index and of the wider body of knowledge that work appears to have settled. It is time to retire the Wharton Index.
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