- September 11, 2017
- Data Visualization
Complementing Harvard’s Map of the Month series, each week, Map Monday highlights a data visualization that enhances understanding of or helps resolve a critical civic issue.
As gentrification has entered the cultural consciousness as a critical social justice problem, questions about affordable housing have become more and more salient. What happens to residents when a city develops economically? What is the current state of affordable housing? Is it possible to have robust development and affordability at the same time?
A story map from Esri, titled Is the American Dream Still Affordable?, seeks to answer these and other questions about affordable housing in the United States. Using 2017 demographic data, the map analyzes changes in American affordable housing between 2012 and 2017 and the current state of affordability for every American county. The map draws upon Esri’s Housing Affordability Index (HAI)—a measure that takes into account median household income, median home value, and mortgage rates—in order to understand the effect of demographic change on local affordability and vice versa.
Overall, the map shows that between 2012 and 2017, housing has become less affordable in the United States. Moreover, major metropolitan areas—such as San Francisco, Los Angeles, New York, and Boston—tend to have the least affordable housing markets.
The analysis attributes this metropolitan concentration of unaffordability to population growth coupled with stagnant provision of housing. Metropolitan areas attracted 96 percent of American population growth between 2010 and 2017, leading to a higher demand for housing. However, the housing supply has not risen alongside this increased demand, meaning that the existing housing stock has become all the more coveted and as a result, expensive.
This map reminds policymakers that in times of rapid population growth, they must facilitate the development of new, affordable housing—whether through zoning or financial incentives for developers. By highlighting areas that have experienced rapid population growth and maintained affordability—cities like Houston, Raleigh, NC, and Midland, TX—the story map showcases potential models for replication.
In order to maximize the effectiveness of these initiatives, cities can mimic the methodology of this mapping effort on a neighborhood-by-neighborhood level, understanding those areas where affordable housing is most needed and directing initiatives accordingly.
Interestingly however, cities that have emphasized affordable housing have run into another problem: affordability can itself attract an influx of residents, increasing demand and undermining the original intent of affordable housing efforts. The analysis accompanying this map points out that the presence of rapid population growth and high affordability in Houston or Raleigh may not imply that these governments have responded effectively to population growth, but rather that affordability has itself led to an influx of residents, which may cause problems in the housing market down the road. These difficulties challenge the prevailing knowledge that population growth is always desirable. While growth brings economic benefit, it must be balanced with the quality of life of existing residents. This map is an apt reminder that demographic changes and economic development must be paired with thoughtful policy.