The
study,
Land-Use Reforms and Housing Costs: Does Allowing for Increased Density Lead to Greater Affordability? is co-authored by a team of seven researchers. Its main finding is that zoning reforms, introduced over the last decade and a half, which loosen restrictions on development, are associated with a very small increase in housing supply, but not with a reduction in housing costs or with greater availability of lower-cost units.
The results showed reforms that loosened restrictions were associated with a 0.8 percent increase in housing units at least three years after the reform was implemented. Those same reforms were not associated with any significant effects on rent. On the other hand, policies that increased restrictions on housing development were associated with small increases in rent, according to the paper.
Like every major study on the effects of housing policy, the data have limitations, the researchers say. It isn’t possible to conduct a true experiment in which one part of a city gets a policy treatment and another does not, says Christopher Davis, a data scientist in the Metropolitan Housing and Communities Policy Center at the Urban Institute, because zoning isn’t the only factor determining how much housing gets built and how much rent costs.