Mobilizing the Vote: Fertile Ground in Detroit
Jeffrey Herbstman, Ph.D.
Data Scientist
Mobilizing the Vote: Fertile Ground in Detroit
Voter Mobilization efforts should focus on a simple equation that indicates the potential available voters in each U.S. census block. The Voter Participation Rate (VPR) as defined as the Voter Totals / Voting Age Citizens located in each block indicates the untapped quantity of voters available in each block.
Using reliable data sets for each of the key variables, VPR indicates the highest potential for blocks for voter mobilization activists in the city. The analysis below suggests that these groups should prioritize the following 5 census blocks:
Census Tract VoterRatio
Census Tract 5240.01 14.3%
Census Tract 5242 14.4%
Census Tract 5241.01 17.6%
Census Tract 5173 20.3%
Census Tract 5234 20.7%
Data Sets:
The data used in this analysis is pulled from two sources. The first is a very interesting data set available here (1), from Michael Bryan and the Harvard Dataverse where they aggregated precinct level voting totals from 2020 and projected them onto U.S. Census geometries. This allows the analysis to bypass known issues with exit polling and use actual voting totals in the calculations. Although this data is reported in a partisan fashion in terms of votes for the president, uses the aggregate total votes across a Census Block for targeting non-partisan voter registration efforts.
The second data set used is data published by the Census on the count of Voting Age Citizens in a given Census Block as calculated by the 2022 5-Year estimates which is the most recent data available for this type of estimate and geography (2).
These data sets provide information on the participation of voters in elections, specifically, the last presidential election as well as the overall available number of voters in a given area, in this case, a Census Block. Census geometries are useful to use in that they can also provide various demographics and other data that is not available for precinct areas.
Calculating VPR
The Vote Totals by Block Group are shown below:
This data shows that the Bagley neighborhood (Blocks 5385 and 5386) seems to have the highest counts, while Southwest Detroit shows less voting overall.
Figure 2 shows the counts of Voting Age Citizens from the Census data:
There are several items to note from this plot. The first is that populations of census blocks vary widely across the city. Most notably, there are several (Belle Isle, the Stellantis Plan on the east side, Rouge Park on the west side, etc.) where the estimated population is 0. These blocks must be taken into account differently as they cause issues with the analysis.
Using these values, the Voter Participation Ratio (Vote Totals per Block / Estimated population of Voting Age Citizens per Block) can be calculated:
This plot shows greyed out Census Blocks where no Voting Age Citizens are estimated to live, these are marked as “NA”. Additionally, there are several Blocks where the projections exceed the estimates from the Census generating a ratio above one. One possibility is that these are Blocks where there was significant decrease in population from 2020 to 2022. Another possibility is that the precinct population from which the projections were drawn is geographically heterogeneous and the projections don’t do a great job for these particular areas. This is likely true for highly industrialized Tract 5245, which shows a ratio of 3.7. The census only estimates that 36 Citizens of Voting Age live in this Block.
If the ratios are capped at 1 by using the Voter Totals as the estimates where the ratio exceeds 1, the plot shows a better looking and more useful chart:
Interestingly, although the prevailing belief is that Detroiters don’t vote, most Blocks have relatively high participation with two thirds of Blocks showing over 50% VPR. Overall, Detroit has a VPR of 56%. Using this data, a list of Census Blocks to target for voter registration and outreach can be generated, including some of the lowest participation Blocks like 5240 (14%), 5242 (14%), 5173 (20%), etc. If voter outreach were to bring these 5 lowest Census Blocks up to the average VPR of 56%, it would boost turnout by 3200 votes in the city.
Bryan, Michael, 2022, "U.S. Voting by Census Block Groups", https://doi.org/10.7910/DVN/NKNWBX, Harvard Dataverse, V3, UNF:6:OlQ9kJRJ1BDUEYRNlqusJA== [fileUNF],
U.S. Census Bureau. "ACS Demographic and Housing Estimates." American Community Survey, ACS 5-Year Estimates Data Profiles, Table DP05, 2022, https://data.census.gov/table/ACSDP5Y2022.DP05?q=DP05&g=050XX00US26163,26163$1400000. Accessed on September 23, 2024.