Racially Polarized Voting in Miami, Florida

Bryant J. Moy, PhD

June 12, 2023

Introduction and Scope of Work

My name is Bryant J. Moy, Ph.D., and I am a faculty fellow in the Center for Data Science and a Visiting

Assistant Professor in the Wilf Family Department of Politics at New York University. My qualifications

were further described in my initial report dated February 10, 2023.

I have been asked to analyze two proposed maps and provide my expert opinion on whether Black voters

could elect their preferred candidates in the newly constituted District 5. I was provided a geolocated voter

file and two shape files containing the geographic boundaries of newly constituted District 5.

In this report, I analyze the performance of the Black-preferred candidate in six recent contests from

2022. Next, I re-analyze five contests from 2020 where I previously showed evidence of racial polarization. I

discuss how the newly proposed maps make it easier for Black voters to translate their preferences to higher

vote totals for their preferred candidate.

Summary of Findings

• Black voters in Miami District 5 cohesively support a single candidate in the six recent elections:

Senate, Governor, County Judge Group 5, Chief Financial Officer, Commissioner of Agriculture, and

Attorney General. Moreover, non-Hispanic white voters’ support for the Black-preferred candidate is

under 50% in all but one of the analyzed contests.

• In the six recent elections, the Black-preferred candidate received the vast majority of the top twocandidate vote share across both newly proposed districts.

• In the re-analysis of five previously polarized contests in 2020, I find that the Black-preferred candidate

would prevail in either of the proposed districts. Moreover, it would be easier for Black voters to

translate their preferences into a higher vote share for their preferred candidate in the two proposed

districts than in the currently constituted one.

1 Black-Preferred Candidates in Recent Elections

In this section, I estimate the extent to which Black voters cohesively support a single candidate and whether

non-Hispanic whites support the Black-preferred candidate. Furthermore, using precinct-level election results, I provide evidence of how the Black-preferred candidate would have performed under the various

District 5 maps. In Table 1, I provide a list of six recently held contests in 2022. I indicate the ethnicity of

the candidate in parentheses: “B” represents Black, “W” represents non-Hispanic white, and “H” represents

Hispanic of any race.

1

Case 1:22-cv-24066-KMM Document 172-7 Entered on FLSD Docket 02/02/2024 Page 1 of 9
Table 1: List of Elections Analyzed

Race Black-Preferred Candidate Non-Black-Preferred Candidate

US Senate Demings (B) Rubio (H)

Governor Crist (W) DeSantis (W)

Attorney General Ayala (B) Moody (W)

Chief Financial Officer Hattersley (W) Patronis (W)

Commissioner of Agriculture Blemur (B) Simpson (W)

County Judge 5 Seraphin (B) Diaz de la Portilla (H)

1.1 Estimating Support for the Black-Preferred Candidate By Race

I analyze the extent to which Blacks and whites support different candidates. As shown in Figure 1, Black

voters cohesively support a single candidate. Indeed, Black voters support their preferred candidate in rates

higher than 80% in all elections analyzed. Non-Hispanic white support for the Black-preferred candidate is

below 50% in all contests but County Judge Group 5.

Figure 1: Estimated Proportion of Support by Race

0.95

0.95

0.94

0.92

0.92

0.91

0.95

0.95

0.94

0.94

0.94

0.93

0.95

0.95

0.94

0.83

0.83

0.83

0.16

0.41

0.42

0.17

0.44

0.45

0.16

0.43

0.45

0.13

0.38

0.4

0.13

0.36

0.38

0.81

0.69

0.69

AG current

AG p1

AG p2

Agr current

Agr p1

Agr p2

CFO current

CFO p1

CFO p2

County_Judge current

County_Judge p1

County_Judge p2

Governor current

Governor p1

Governor p2

Senate current

Senate p1

Senate p2

0.00 0.25 0.50 0.75 1.00

Estimated proportions of Support among Blacks and Whites

Race: Map

2

Case 1:22-cv-24066-KMM Document 172-7 Entered on FLSD Docket 02/02/2024 Page 2 of 9
1.2 Performance of Black-Preferred Candidate in Recent Elections

Using precinct-level results of six elections held in 2022, I aggregate results to determine how many votes the

Black-preferred candidate would have received within the boundaries of the two newly constituted districts

(See Table 2). The two-candidate vote shares were similar across proposed districts.1 Yet, the Black-preferred

candidate would have prevailed in all contests analyzed at the district-level.

Table 2: Black-Preferred Candidate Performance in Recent Election

Race Map Vote Total2 Black-Pref. # Black-Pref. % Non-Black-Pref. # Non-Black-Pref. %

County Judge Grp 5 Current 6473 5046 77.95% 1427 22%

County Judge Grp 5 1 6567 5124 78% 1443 22%

County Judge Grp 5 2 6698 5220 78% 1478 22%

US Senate Current 14370 11741 81.7% 2629 18.3%

US Senate 1 14483 11784 81.36% 2699 18.6%

US Senate 2 14859 12047 81% 2812 18.9%

Governor Current 14392 11523 80% 2869 20%

Governor 1 14500 11555 80% 2945 20%

Governor 2 14875 11812 79.4% 3063 20.5%

Attorney General Current 14300 11424 80% 2876 20%

Attorney General 1 14418 11462 79.5% 2956 20.5%

Attorney General 2 14793 11730 79.3% 3063 20.7%

CFO Current 14200 11470 80.8% 2730 19.2%

CFO 1 14324 11505 80.3% 2819 19.7%

CFO 2 14696 11764 80% 2932 20%

Comm. of Agriculture Current 14273 11689 81.9% 2584 22.1%

Comm. of Agriculture 1 14396 11724 81.4% 2672 18.6%

Comm. of Agriculture 2 14766 11986 81.2% 2780 18.8%

2 Black-Preferred Candidate Performance in Previously Racially

Polarized Elections

Table 3: Black-Preferred Candidate Performance in Previous RPV Elections

Race Map Vote # Black-Pref. # Black-Pref. % Non-Black-Pref. # Non-Black-Pref. %

President Current 30418 25648 84.3% 4770 15.7%

President 1 34422 28462 82.7% 5960 17.3%

President 2 35032 28935 82.6% 6097 17.4%

County Mayor Current 26889 22159 82.4% 4730 17.6%

County Mayor 1 30509 24845 81.4% 5664 18.6%

County Mayor 2 31059 25262 81.3% 5797 18.6%

County Judge Grp 9 Current 10335 6933 67% 3402 32.9%

County Judge Grp 9 1 11686 7631 65.3% 4055 34.7%

County Judge Grp 9 2 11867 7744 65.2% 4123 34.7%

Circuit Judge Group 57 Current 10654 7380 69% 3274 30.7%

Circuit Judge Group 57 1 12016 8103 67.4% 3913 32.6%

Circuit Judge Group 57 2 12200 8227 67.4% 3973 32.6%

Circuit Judge Group 67 Current 10407 6079 58.4% 4328 41.6%

Circuit Judge Group 67 1 11779 6646 56.4% 5133 43.6%

Circuit Judge Group 67 2 11958 6751 56.4% 5207 43.5%

In this section, I re-analyze five 2020 contests that showed signs of racial polarization in my previous

report: President, County Mayor, County Judge Group 9, Circuit Judge Group 57, and Circuit Judge Group

1. I use the top two candidate vote totals to examine the contest’s Black-preferred and non-Black-preferred candidates.

3

Case 1:22-cv-24066-KMM Document 172-7 Entered on FLSD Docket 02/02/2024 Page 3 of 9
67. In Table 3, I aggregate the official election results for each district and show how many votes the Blackpreferred candidate would have received under each map. Across all contests, the Black-preferred candidate

would have received the majority of the votes in District 5.

Figures 2 - 6 depicts the relationship between the Black share of the electorate and the share that the

Black-preferred candidate received. Each dot represents a precinct and corresponds to the share of Black

registered voters and the two-candidate vote share in that precinct. I report the correlation coefficient in

the top left of each figure. These correlation coefficients are bounded from -1 to +1. Numbers closer to 1

indicate that Black voters are able to translate their preferences into their preferred candidate’s vote share.

As we see in the figures, Black voters can better translate their preferences into higher vote shares in the

two proposed districts than in the current District 5. For all contests, the correlation coefficient is larger

and closer to one in the two proposed districts.

Figure 2: Presidential Election

R = 0.52, p = 0.0022

0.00

0.25

0.50

0.75

1.00

0.00 0.25 0.50 0.75 1.00

Black Share of the Electorate

Black−Preferred Candidate

Current District 5

R = 0.87, p = 7.7e−10

0.70

0.75

0.80

0.85

0.90

0.95

0.25 0.50 0.75

Black Share of the Electorate

Black−Preferred Candidate

Proposed Map 1

R = 0.86, p = 1.6e−09

0.70

0.75

0.80

0.85

0.90

0.95

0.25 0.50 0.75

Black Share of the Electorate

Black−Preferred Candidate

Proposed Map 2

4

Case 1:22-cv-24066-KMM Document 172-7 Entered on FLSD Docket 02/02/2024 Page 4 of 9
Figure 3: County Mayor

R = 0.47, p = 0.0061

0.00

0.25

0.50

0.75

1.00

0.00 0.25 0.50 0.75 1.00

Black Share of the Electorate

Black−Preferred Candidate

Current District 5

R = 0.79, p = 3.1e−07

0.65

0.70

0.75

0.80

0.85

0.90

0.25 0.50 0.75

Black Share of the Electorate

Black−Preferred Candidate

Proposed Map 1

R = 0.77, p = 5.9e−07

0.65

0.70

0.75

0.80

0.85

0.90

0.25 0.50 0.75

Black Share of the Electorate

Black−Preferred Candidate

Proposed Map 2

5

Case 1:22-cv-24066-KMM Document 172-7 Entered on FLSD Docket 02/02/2024 Page 5 of 9
Figure 4: County Judge Group 9

R = 0.63, p = 0.00013

0.4

0.5

0.6

0.7

0.8

0.00 0.25 0.50 0.75 1.00

Black Share of the Electorate

Black−Preferred Candidate

Current District 5

R = 0.92, p = 3e−12

0.5

0.6

0.7

0.8

0.25 0.50 0.75

Black Share of the Electorate

Black−Preferred Candidate

Proposed Map 1

R = 0.91, p = 3.4e−12

0.5

0.6

0.7

0.8

0.25 0.50 0.75

Black Share of the Electorate

Black−Preferred Candidate

Proposed Map 2

6

Case 1:22-cv-24066-KMM Document 172-7 Entered on FLSD Docket 02/02/2024 Page 6 of 9
Figure 5: Circuit Judge Group 57

R = 0.67, p = 3.2e−05

0.4

0.5

0.6

0.7

0.8

0.00 0.25 0.50 0.75 1.00

Black Share of the Electorate

Black−Preferred Candidate

Current District 5

R = 0.79, p = 3.6e−07

0.6

0.7

0.8

0.25 0.50 0.75

Black Share of the Electorate

Black−Preferred Candidate

Proposed Map 1

R = 0.79, p = 2.3e−07

0.6

0.7

0.8

0.25 0.50 0.75

Black Share of the Electorate

Black−Preferred Candidate

Proposed Map 2

7

Case 1:22-cv-24066-KMM Document 172-7 Entered on FLSD Docket 02/02/2024 Page 7 of 9
Figure 6: Circuit Judge 67

R = 0.52, p = 0.0027

0.2

0.4

0.6

0.00 0.25 0.50 0.75 1.00

Black Share of the Electorate

Black−Preferred Candidate

Current District 5

R = 0.9, p = 3.8e−11

0.45

0.55

0.65

0.75

0.25 0.50 0.75

Black Share of the Electorate

Black−Preferred Candidate

Proposed Map 1

R = 0.9, p = 1.7e−11

0.45

0.55

0.65

0.75

0.25 0.50 0.75

Black Share of the Electorate

Black−Preferred Candidate

Proposed Map 2

8

Case 1:22-cv-24066-KMM Document 172-7 Entered on FLSD Docket 02/02/2024 Page 8 of 9
Summary

In this report, I analyzed two newly proposed maps for District 5. I analyzed six recent elections and found

that Black support in this district is cohesive. Moreover, in those elections, the Black-preferred candidate

will receive the majority of the votes in the newly proposed districts. Lastly, I re-analyze five contests that

previously showed evidence of racial polarization. The Black-preferred candidate would prevail in either of

the two proposed districts. More importantly, Black voters can better translate their numbers into higher

vote shares for their preferred candidate in the two proposed districts.

Bryant J. Moy, Ph.D.

Date: June 12, 2023

9

Case 1:22-cv-24066-KMM Document 172-7 Entered on FLSD Docket 02/02/2024 Page 9 of 9