The Link Between Local Comprehensive Plans and Housing Affordability: A Comparative Study of the Atlanta and Detroit Metropolitan Areas

Abstract

Problem, research strategy, and findings: I question whether the strength of affordable housing policies in local comprehensive plans is associated with better affordable housing outcomes, which I measure as a decrease in the share of low-income households who spend more than 30% of their income for housing, otherwise known as cost-burdened households. I first assess the strength of affordable housing policies in 58 local comprehensive plans, counting the number of—and degree of coercion in—those affordable housing policies. I then analyze the relationship between the strength of affordable housing policies and changes in the share of low-income households with cost burden. I find that the strength of affordable housing policies is higher in the Atlanta (GA) metropolitan area than in the Detroit (MI) metropolitan area. I also find that the strength of affordable housing policies is positively associated with a decrease in the share of low-income households paying more than 30% of their income for housing in the Atlanta metropolitan area. I do not find a comparable relationship between plan strength and housing outcomes in the Detroit metropolitan area. I also find that the state role matters: Georgia provides more support and guidance for local comprehensive planning, and for affordable housing policies in those plans, than does Michigan.Takeaway for practice: Planners should continually promote local comprehensive plans that include more and stronger affordable housing policies and advocate for greater state support for comprehensive planning and affordable housing policies because these appear to lead to a greater likelihood of implementing stronger plans.