Everyone knows that voter turnout can decide an election; but most studies of voter turnout only focus on national presidential elections. Because local elections can have more practical impact on people's everyday lives, the Knight Foundation wanted to understand how voter turnout trends are different local mayoral elections. They approached us and our partners at Portland State University to create a new, nation-wide data set measuring voter participation in the last three local elections.
First, we worked with PSU and Knight to identify 40 different cities that would provide a representative sample of diverse population demographics. We then gathered raw voter data files from each city, county or state for each primary and general election where local candidates or issues were on the ballot. Based on the voter files, we then computed census tract level aggregates for over 40 different variables based on residence addresses. Finally, we cross-referenced the data with indicators from American Community Survey to develop aggregate profiles for each census tract.
Knight also wanted to share the results with a wider audience, with the hope that the data could help to influence placement of get-out-the-vote (GOTV) efforts in communities where turnout was low. We developed a website, Who Votes For Mayor, to display the results. In the interest of supporting further research, the data is all publicly available through the website.
The final result
The final data set included over 60 million voter turnout records across 40 cities and three elections. We aggregate results for more than 12,000 census tracts across 43 different variables. The project lasted just over 8 months, and laid the groundwork for further research and alignment between local voting patterns and national results, as well as unique insights into neighborhood level equity and civic-participation challenges.