Hostname: page-component-76d6cb85b7-vdhp9 Total loading time: 0 Render date: 2026-07-14T17:55:35.241Z Has data issue: false hasContentIssue false

A Logical Model for Predicting Minority Representation: Application to Redistricting and Voting Rights Cases

Published online by Cambridge University Press:  25 June 2021

YUKI ATSUSAKA*
Affiliation:
Rice University, United States
*
Yuki Atsusaka, PhD Candidate, Department of Political Science, Rice University, United States, atsusaka@rice.edu.
Rights & Permissions [Opens in a new window]

Abstract

Understanding when and why minority candidates emerge and win in particular districts entails critical implications for redistricting and the Voting Rights Act. I introduce a quantitatively predictive logical model of minority candidate emergence and electoral success—a mathematical formula based on deductive logic that can logically explain and accurately predict the exact probability at which minority candidates run for office and win in given districts. I show that the logical model can predict about 90% of minority candidate emergence and 95% of electoral success by leveraging unique data of mayoral elections in Louisiana from 1986 to 2016 and state legislative general elections in 36 states in 2012 and 2014. I demonstrate that the logical model can be used to answer many important questions about minority representation in redistricting and voting rights cases. All applications of the model can be easily implemented via an open-source software logical.

Information

Type
Research Article
Creative Commons
Creative Common License - CCCreative Common License - BY
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
Copyright
© The Author(s), 2021. Published by Cambridge University Press on behalf of the American Political Science Association
Figure 0

Figure 1. How the Racial Margin of Victory Relates to Other FactorsNote: The racial margin of victory ($ M $) is a function of the vote shares of the top minority and white candidates in the most recent election ($ {V}_{t-1}^M,{V}_{t-1}^W $). These vote shares are in turn functions of three factors (U): the proportion and turnout of minority voters, degree of minority bloc and white crossover voting, and strategic coordination among minority and white candidates. U depends on various factors (T), including district partisanship, incumbency, geographical concentration of minorities, urbanization, residential segregation, and historical factors.

Figure 1

Figure 2. Quantitative Predictions of the Logical ModelNote: This figure visualizes the probability of minority candidate emergence against $ {(MC)}^{1/2}-50 $ (the estimated future racial margin of victory) (Panel A) and $ M $ with varying values of $ C $ (% minority voters) (Panel B).

Figure 2

Figure 3. Model Predictions with Observed Minority Candidate EmergenceNote: This figure shows the observed minority candidate emergence in Louisiana mayoral elections over the model predictions. It illustrates that most elections with Black candidates ($ \circ $) are located in the upper-right region (where $ {P}_{\mathrm{run}}>0.9 $) and most elections without Black candidates ($ \times $) appear in the lower-left area (where $ {P}_{\mathrm{run}}<0.1 $).

Figure 3

Table 1. Predictive Performance of the Logical Model Relative to Regressions

Figure 4

Figure 4. Model Predictions with Observed Minority Electoral SuccessNote: This figure shows the observed minority electoral success in state legislative general elections in 36 states over the model predictions. It illustrates that most elections with minority winners are located in the upper-right region (where $ {\hat{P}}_{\mathrm{win}}>0.9 $) and most elections without minority winner appear in the lower-left area (where $ {\hat{P}}_{\mathrm{win}}<0.1 $).

Figure 5

Table 2. Predictive Performance of the Logical Model in State Legislative General Elections

Figure 6

Figure 5. Application of the Logical Model to Redistricting and Voting Rights CasesNote: This figure illustrates how the logical model can be used to predict the probability of minority electoral success at fixed $ C $ with varying levels of white crossover (Panel A), assess the effect of increasing the percentage of minority voters on minority electoral success (Panel B), discover the sufficient percentages of minority voters to yield a prespecified probability of minority electoral success, the sweet spot of redistricting, and the degree of potential vote dilution via packing (Panel C), and predict the number of minority officeholders in a jurisdiction with multiple districts (Panel D).

Supplementary material: Link

Atsusaka Dataset

Link
Supplementary material: PDF

Atsusaka supplementary material

Atsusaka supplementary material

Download Atsusaka supplementary material(PDF)
PDF 381.6 KB
Submit a response

Comments

No Comments have been published for this article.