September 20, 2018
By Emily F. Keller
Quantifying Displacement of Seattle and King County Residents

As home rental and real estate prices have skyrocketed across the Seattle metropolitan area, two University of Washington researchers are developing methods to measure the displacement of city and King County residents.

Timothy Thomas, a Postdoctoral Fellow at the UW eScience Institute and the Department of Sociology, and Michael Babb, a computational geographer and PhD student in the UW Department of Geography, are analyzing public and private data to identify socio-demographic characteristics of people who move to and from specific neighborhoods extending outward from the Seattle core. The Neighborhood Change Project examines migration patterns and housing market data to assess how increases in rental and home prices have created economic barriers to residents based on race, income and education.

To conduct their work, Thomas and Babb are combining public data from the Census Bureau’s American Community Survey and Decennial Census that gathers local information on population demographics, jobs, housing, race, income, and education; and real estate and rental listings data from Zillow. The data sets span 40 years to highlight distinctions before and after several economic shocks: the 2007-2009 recession, the ongoing local housing crisis and the growth of tech companies such as Google, Microsoft and Amazon in the Seattle metropolitan area. Aggregating these data sources, the researchers can map the inflow and outflow of residents within the Seattle metropolitan area, beyond King County, and to other states and countries.

Thomas and Babb’s methods combine demographic and sociological theory with quantitative and data science techniques to investigate concepts around migration, racial segregation, housing and residential displacement. Their innovative data science methods involve merging disparate datasets in new ways through a spatial linking process that standardizes geographic boundaries to account for changes over time. Theories and analyses on changing population mobility, socioeconomics, racial differences in neighborhood segregation and housing help inform potential interactions with shifts in metropolitan economic and business dynamics. Through these methods, Thomas and Babb have been able to develop some of the first models that quantify residential displacement in the Puget Sound area. The project builds on their diverse academic backgrounds. Thomas’s work uses sociological methods and data analytics to study residential micro-segregation, gentrification, neighborhood change, housing inequality and evictions. Babb’s work focuses on analyzing population geography, migration patterns and spatial-demographics trends and inequalities.

Click to view the researchers’ Tier Theory graphic

Based on early project results, the researchers posit a causal sequence between overlapping trends in the data over the past two decades, highlighting migration from Seattle and King County to outlying areas. They have reached several conclusions: 1. Seattle’s urban core (tier 1) and neighborhoods to the north are experiencing in-migration from mostly out-of-state, high-income residents, many of whom are white. 2. Middle-income residents from tier 1 and across the county, who are also largely white, are migrating to neighborhoods within Seattle and Bellevue with lower housing prices (tier 2) that were largely lower-income, racially-diverse populations prior. 3. Former tier 2 residents, who are largely non-white, are migrating further from the Seattle core to formerly white and rural areas (tier 3), often to the south, such as Kent and Renton. Thomas and Babb are working to model how each transition contributes to an increase in housing demand and prices, to provide a breakdown of the neighborhoods that have become unaffordable for specific demographic groups.

The project will generate micro-level data underlying local trends in population growth and housing affordability. As the number of Seattle residents has increased from 608,660 in 2010 to 724,745 in 2017, according to the U.S. Census Bureau, regional housing costs have climbed significantly. According to the Seattle Times, single-family-home values in King, Snohomish and Pierce counties have risen at a faster pace than any other city in the country since mid-2016, with the biggest increases for smaller starter homes in outlying areas. In May 2018, the median price of a single-family-home was $830,000 in Seattle, and $726,275 in King County, showing double-digit increases from one year prior, according to the Northwest Multiple Listing Service. The median monthly rent was estimated at $2,488 in Seattle, and $2,179 in the metropolitan area in May 2018, according to Zillow statistics. Among the area’s major cities, the highest increases over the last year were seen in Tacoma, Everett and Renton.

== Role of the Cascadia Urban Analytics Cooperative ==

The project, which is sponsored in part by the Cascadia Urban Analytics Cooperative (CUAC), is part of a broader programmatic focus on studying the relationship between housing affordability, health, neighborhood opportunities and transportation by researchers at the UW and the University of British Columbia (UBC). At the CUAC Symposium last September, interdisciplinary participants from UW, UBC and public agencies discussed these issues in the Cascadia region.

Thomas and Babb are working in coordination with another CUAC-affiliated research project called “HEALTHY cities: How Environments And Local Transport impact Health thru data analYitics.” This project explores relationships between social determinants of health (such as transportation access, neighborhood demography, and health behavior) and neighborhood health outcomes in Seattle and Vancouver, to create a predictive model that will inform local and regional policies. The project is led by Susan Dahinten and Leanne Currie, Associate Professors at the UBC School of Nursing; Uba Backonja, Assistant Professor in Nursing and Healthcare Leadership at UW Tacoma; and Martino Tran, Assistant Professor at the UBC School of Community & Regional Planning.

== Next Steps ==

The end goal of this research is to (1) understand the extent and mechanisms of residential displacement through neighborhood change in Seattle and the US; (2) publish findings in peer review journals; and (3) provide an online tool for policymakers, practitioners, and the public to understand how changes in the local political economy affects population displacement.

== Talks ==

Thomas and Babb have cited their research in multiple talks this year:

  • 7/31/18: Eviction Ecology: Local and Extra-Local Effects (in the Puget Sound Region) - The American Sociological Association Annual Meeting. Philadelphia Convention Center, Philadelphia, PA - Tim Thomas
  • 6/4/18: Neighborhood Change and Rent: Who’s Vulnerable to Gentrification - Seattle Renter’s Commission. City Hall, Seattle, WA (a public forum on rent control) - Tim Thomas
  • 5/19/18: Spatial-Temporal Trends in IRS County to County Migration Data: 1990 – 2015 – Association of Washington Geographers Spring Meeting, Western Washington University - Mike Babb
  • 5/17/18: Segregation and Housing: From Jim Crow to Gentrification - UW Tacoma - Tim Thomas
  • 5/7/18: Forced Evictions, Gentrification, and Race: Seattle & King County - Seattle Office of Arts & Culture, Seattle, WA - Tim Thomas
  • 4/26/18: Neighborhood & Demographic Disparities in Eviction - Population Association of America, Denver, CO - Tim Thomas
  • 4/26/18: Health & Neighborhood Racial Segregation: A Multi-Metropolitan Comparison - (w/ Michael Esposito) Population Association of America Annual Meeting, Denver, CO - Tim Thomas