Abstract
To further the understanding of how land use regulation affects housing supply, in this paper I assess the causal impact on multifamily housing development of a significant change in zoning policy that took place in Seattle. This policy dramatically changed zoning regulations and allowed for more dense housing to be bult through in most of the city’s multifamily zones. I avoid the empirical challenge of quantifying variation in the stringency of regulation by using the synthetic control technique to estimate treatment effects of this one instance of zoning reform. I use data from the US Census on the number of multifamily residential building permits issued in each year across US localities from 2006 until 2021. The bulk of the reforms in Seattle took place in 2019, and I estimate that in 2021 Seattle added 5,251 additional multifamily units as a result of the policy change. The findings of this paper provide evidence that relaxing restrictive zoning regulation may significantly increase the development of residential housing.