1. Voter Suppression and the Ecological Fallacy: A Colorado Case Study
Dr. Paul C. Sutton
Department of Geography & the Environment
University of Denver
Association of American Geographers
Tampa, Florida April 9th, 2012

2. The Political Game Raising Barriers to Voting with Predictable Consequences
In late 2011, the republican secretary of state for Colorado announced that the state’s mail-in ballots would henceforth only be sent out automatically to those who were ‘active’ voters, meaning they had voted in the last general election.
The county clerks of Denver and Pueblo counties were concerned this would have a discriminatory impact on Black and Hispanic voters in their counties.

3. The Team
Denver and Pueblo counties worked with the Brennan Center for Justice and Colorado Common Cause to fight Gessler’s new mandate.
Seth Masket (DU Poly Sci professor) and I were consulted for the spatio-demographic analysis of the consequences of this mandate were it to be implemented.

4. The Data: Voter Registration Precincts

5. The Modifiable Areal Unit Problem Merging Census & Voter Registration Data
Census Block Group Data with
Aggregrate Demographic Info
Counts of Black
Counts of Hispanic
Counts of White
Are in RED
Voting Precinct Data with
Aggregate voter Info
Counts of IFTV
Counts of Voters
Are in BLACK
Assume homogeneity within
Census block group polygons.

6. The Null Hypotheses
#1) The proportion of ‘Inactive Failed to Vote’ designations in the voting precincts is unrelated to the proportion of African American persons in those precincts.
#2) The proportion of ‘Inactive Failed to Vote’ designations in the voting precincts is unrelated to the proportion of Hispanic persons in those precincts.
#3) The proportion of ‘Inactive Failed to Vote’ designations in the voting precincts is unrelated to the proportion of White persons in those precincts.

7. Statistical Analysis #1 % IFTV and % White
The Higher the proportion of
Inactive Failed to Vote (IFTV)
The Lower the percentage of
Population that is White.
Statistically Significant

8. Statistical Analysis #2 % IFTV and % Hispanic
The Higher the proportion of
Inactive Failed to Vote (IFTV)
The Higher the percentage of
Population that is Hispanic.
Statistically Significant

9. Statistical Analysis #3 % IFTV and % Black
The Higher the proportion of
Inactive Failed to Vote (IFTV)
The Higher the percentage of
Population that is Black.
Statistically Significant

10. The Conclusions
#1) The proportion of ‘Inactive Failed to Vote’ designations in the voting precincts is unrelated to the proportion of African American persons in those precincts.
REJECTED
#2) The proportion of ‘Inactive Failed to Vote’ designations in the voting precincts is unrelated to the proportion of Hispanic persons in those precincts.
#3) The proportion of ‘Inactive Failed to Vote’ designations in the voting precincts is unrelated to the proportion of White persons in those precincts.

11. The Caveats We have two problems
1) The Modifiable Areal Unit Problem (MAUP) with the merging of Voting Precinct data with Census Block Group Data.
2) The Ecological Fallacy
In this case high % IFTV and high % Black correlate. Our conclusion would be wrong if the whites (or non-blacks) in high % black voting precincts were extremely more likely to have been IFTV (same with precincts with high % Hispanic)
There is NO evidence to support this.
The numbers are so extreme that some voter suppression would have been inevitable.

12. The Maps % IFTV, % Black, %Hispanic, and % White in Denver

13. Summary of Court Findings
The Court emphasized that Colorado law prohibited “any elector’s registration record from being canceled solely for failure to vote” but that the Secretary's interpretation of the law would have required some voters who had missed a single election to “re-register” to vote, “effectively penaliz[ing]” citizens “for not voting.” This would have “impeded the voting of some 4,000 – 6,000 IFTV electors in Denver in November 2011 … and tens-of-thousands of citizens statewide.”

14. Questions and/or Comments?
Some URLs that may be of interest on this topic:
Seth Masket’s blog
UCSB summary
Brennan Center for Justice Summary