Reliability of Homogeneous Precinct Analysis Undermined since Small Majorities provide Insufficient Data for such Analysis; Court limits the Testimony of Political Science Expert Witness amidst claims of Racially Polarized Voting

Reliability of Homogeneous Precinct Analysis Undermined since Small Majorities provide Insufficient Data for such Analysis; Court limits the Testimony of Political Science Expert Witness amidst claims of Racially Polarized Voting

This case concerned claims brought by Plaintiffs Miguel Coca and Alejandro Rangel-Lopez under Section 2 of the Voting Rights Act (“VRA”) and the Fourteenth Amendment’s Equal Protection Clause. Plaintiffs alleged that Defendants, the City of Dodge City and members of the Dodge City Commission, violated Section 2 by holding at-large elections for Commission seats. To support their claims at both summary judgment and trial, Plaintiffs submitted expert reports from Matthew Barreto and Rubén Martinez.

Barreto’s qualifications as an expert in voting rights cases were undisputed, and the Court found no need to enumerate them. It was established that Barreto possessed commendable credentials, significant acclaim, and a deep immersion in the academic discourse on voting rights in the United States, particularly concerning Latino voters. He was also a coauthor of eiCompare, a software designed for analyzing election results to evaluate racially polarized voting. At the time, Barreto held a teaching position at the University of California, Los Angeles (“UCLA”). The current case originated from a class project supervised by Barreto at UCLA, where he, along with attorney Chad Dunn, co-founded the UCLA Voting Rights Project. Notably, attorneys from the UCLA Voting Rights Group, including Chad Dunn, represented Plaintiffs in the case.

In the context of the present case, Plaintiffs relied on Barreto’s expert opinion to demonstrate that racially polarized voting existed in Dodge City, meeting the criteria outlined in the second and third Gingles factors. This reliance on Barreto’s testimony aimed to support the Plaintiffs’ claim under Section 2 of the Voting Rights Act, specifically regarding vote dilution, as established in Thornburg v. Gingles, 478 U.S. 30, 50 (1986).

In formulating his opinion, Barreto employed homogenous precinct analysis and ecological inference analysis, considering both endogenous and exogenous elections. His ultimate conclusion was that both Hispanics and whites in Dodge City consistently voted en bloc, and the cohesive white bloc votes hindered the election of preferred Hispanic candidates.

Barreto’s examination encompassed four Commission elections spanning from 2014 to 2021, along with an additional 20 general elections between 2014 and 2022. During the November 2022 general election, he asserted there were 11,743 registered voters across nine precincts in Dodge City, with 4,037 voters within the “three majority-Latino precincts.” However, Barreto did not specify which precincts were considered Latino-majority, nor did he provide supporting numbers or other population data for this claim. Nevertheless, data from the 2021 Commission election did indicate the three precincts with the highest Latino voter population: Precinct 3 with 59.9% Latino voters, Precinct 2 with 54.5% Latino voters, and Precinct 1 with 39.1% Latino voters.

Plaintiff also introduced the expert opinions of Ruben Martinez, who served as the Director of the Julian Samora Research Institute at Michigan State University, focusing on supporting Latino communities in the Midwest. His scholarly work concentrated on social inequality, intergroup relations, social movements, and political power.

Before this case, Martinez had not engaged in any research or analysis related to Kansas history, Dodge City history, the Voting Rights Act, or election systems. Additionally, he had no prior studies on the impact of at-large voting systems versus multi-district voting systems on any specific population.

In preparation for his testimony in this case, Martinez conducted a review of various sources related to historical segregation in Dodge City. He also spent two days physically present in Dodge City, during which he informally interviewed an individual who expressed concerns about the City’s delayed efforts to pave brick streets in his neighborhood. Notably, Martinez did not take substantial notes during the meeting, could not recall the interview’s location, and did not request the individual’s name. Additionally, he spent some time driving around Dodge City, claiming the ability to distinguish between Hispanic and white neighborhoods from his car.

The Defendants’ motion for summary judgment, integral to the case, was awaiting the Court’s decision. The focal point of the summary judgment motion was the present Motions to Exclude, wherein Defendants aimed to prevent the inclusion of Plaintiffs’ expert testimony on racially polarized voting in Dodge City and historical discrimination in the same area. Therefore, the Defendants sought to bar these reports, putting forth various grounds for exclusion. 

Dr. Matthew A. Barreto holds a Ph.D. in Political Science from the University of California, Irvine. His doctoral studies focused on American politics, race and ethnicity in politics, and political methodology. He also holds a Master’s degree in Social Science from UC Irvine and a Bachelor’s degree in Political Science from Eastern New Mexico University. Barreto currently serves as a Professor of both Political Science and Chicana/o Studies at the University of California, Los Angeles. Additionally, he holds positions as Co-Founder and Faculty Director of the Latino Policy & Politics Initiative and the UCLA Voting Rights Project. 

Dr. Rubén O. Martinez holds a Ph.D. in Sociology from the University of California, Riverside. He also obtained his Master’s in Sociology from Arizona State University and a Bachelor’s degree With Distinction in Behavioral Science from the University of Southern Colorado. His areas of specialization include sociological theory, social stratification, and race and ethnic relations. Ruben Martinez is a professor emeritus of sociology at Michigan State University and is also the editor of the Latinos in the United States Book series published through Michigan State University Press.

Rule 702 of the Federal Rules of Evidence governs the admissibility of expert testimony. The Court’s responsibility is to assess the expert’s qualifications, reliability of methods, and relevance to the case. The burden lies with the party presenting the expert testimony to demonstrate admissibility. The Court has the discretion to perform its gatekeeping function under Daubert, especially in bench trials, where it has greater leeway in admitting evidence. In this case, the Court determined that a Daubert hearing was unnecessary, and it could decide the motions based on the parties’ briefs. The Court emphasized that the focus is on preventing unreliable scientific evidence from reaching the jury.

The Defendants argued for the exclusion of Matthew Barreto’s report, contending that it was scientifically unreliable. Their objections centered on Barreto’s use of homogeneous precinct analysis and ecological inference analysis. Additionally, the Defendants asserted that Barreto exhibited bias to such an extent that his entire testimony should be excluded. The Court proceeded to address each of these arguments individually.

First, the Defendants contended that Barreto’s homogeneous precinct analysis, or extreme case analysis, lacked sufficient data and should be excluded under Daubert. Homogeneous precinct analysis (HPA), widely referred to as “extreme case analysis”, a recognized method used by Courts in determining racial polarization, involves examining voting percentages in racially homogeneous precincts. For example: In a precinct where the voter population is predominantly Hispanic, it was suggested that the preferred candidate of Hispanic voters could be inferred if any candidate received a substantial majority of votes. This analysis is pertinent to the second and third Gingles preconditions, providing insights into whether minority and white voters cast vote in blocs. 

Barreto’s report claims there are three majority-Latino precincts as of the November 2022 election. However, he fails to identify those precincts, share the percentage of the Latino population within, or even provide a citation for this statement. The only concrete data presented to the Court indicated that in 2021, only two precincts had a majority Latino population: Precinct 2 with 54.5% Latino voters and Precinct 3 with 59.9% Latino voters. The third-highest Latino percentage was in Precinct 1, where Latinos comprised 39.1% of the eligible voting population.

The present motion originated from the Defendants’ argument that the small majorities in certain precincts provided insufficient data for a reliable homogeneous precinct analysis (HPA). Citing recent cases from the Eastern District of Michigan and the Eastern District of California, Defendants asserted that HPA is only reliable when the ethnic minority comprises 90% or more of the precinct’s population. In contrast, Plaintiffs, without citing any supporting cases, referred to scholarly articles, including two written by Barreto, stating that HPA applies even when a minority population is 50% or greater in a given precinct.

The Court, upon review, found that Barreto’s HPA, based on precincts with a Latino Citizen Voting Age Population (CVAP) of less than 60% and one with a 39.1% Latino CVAP, would not be helpful to the trier of fact. The Court noted that existing case law, like, Large v. Fremont Cnty., 709 F. Supp. 2d 1176, 1197 (D. Wyo. 2010), tends to agree that HPA is unhelpful when the ethnic minority population is less than 90% in each precinct. The Court expressed uncertainty about Barreto’s reliable application of HPA principles and methods to the dataset, especially considering the absence of statistical data to assess potential demographic changes between 2021 and 2022.

The Court observed that no precinct had a minority CVAP of 90% or greater, which aligns with the concept of HPA where the precinct’s homogeneity allows for the inference of racially polarized voting. Since there were no homogeneous precincts, the Court determined that HPA would not be helpful to the trier of fact. The Court found it implausible to consider a 60% ratio, as urged by the Plaintiff, as sufficient, stating that such a ratio would be speculative and inconsistent with HPA’s nature as an “extreme case analysis.” Consequently, the Court deemed Barreto’s HPA unreliable, asserting that it would not assist the trier of fact due to being based on insufficient facts and data. As a result, the Court granted Defendants’ Motion to exclude Barreto’s HPA analysis in this case.

The second analysis Barreto relied on ecological inference (EI), an inferential analysis promoted by Barreto himself through the development of his eiCompare software. EI had gained broad acceptance in Courts handling vote dilution cases. However, Defendants contested Barreto’s use of this technique on three grounds: (1) the failure to include confidence intervals (margin of error); (2) inadequate data concerning endogenous elections; and (3) improper reliance on exogenous elections.

Defendants stressed the importance of considering the known or potential rate of error in a particular scientific technique, quoting Daubert. They highlighted that, the Reference Manual on Scientific Evidence encourages the use of “confidence intervals” and other margins of error, defining the former as, “An estimate, expressed as a range, for a parameter. For estimates such as averages or rates computed from large samples, a 95% confidence interval is the range from about two standard errors below to two standard errors above the estimate. Intervals obtained this way cover the true value about 95% of the time.”

Defendants, while not disputing the ecological inference (EI) technique or Barreto’s qualifications, contended that his EI analysis was unreliable due to the absence of confidence intervals or other margin of error analysis in his report. Although acknowledged as relevant to a Daubert analysis, Defendants couldn’t cite any voting dilution case where an expert was excluded solely for this reason. Voting rights cases generally appeared to accept that confidence intervals might be unnecessary in this context. The Court noted that discussions about experts’ use of confidence intervals typically occurred after bench trials, suggesting that the absence of confidence intervals could be addressed post-trial without implicating the Court’s gatekeeping function under Daubert. The Court concluded that Barreto’s report wasn’t inherently unreliable for lacking confidence intervals, and thus, the Court did not exclude it on this basis.

Endogenous elections are those which involve the elected office at issue in the case at bar. In this case, Barreto referred to endogenous elections as those where citizens elected Commission members through the at-large voting system. Defendants argued that Barreto’s analysis, based on only four elections in a city with nine precincts, had an insufficient sample size to form a reliable opinion. They referenced Cisneros v. Pasadena Indep. Sch. Dist., CIVIL ACTION NO. 4:12-CV-2579 (S.D. Tex. Apr. 25, 2014), where Barreto himself testified about the challenges of limited data in endogenous elections, citing the small number of precincts as a complicating factor in analyzing voting patterns. The Court considered this argument in evaluating the reliability of Barreto’s analysis.

The Court acknowledged the irony in Defendants’ argument about limited data in endogenous elections, given that Barreto’s most recent methodology, Bayesian Improved Surname Geocoding (“BISG”), was developed to address such situations after the Cisneros case. Plaintiffs countered by asserting that BISG was specifically designed for limited data pools, and Defendants did not respond to this claim.

Despite the sparse data from endogenous elections, the Court was not inclined to deem four elections, nine precincts, and one polling location as legally insufficient for Barreto to draw conclusions. The Court noted that the sparsity of the data could be considered during the trial to assess the weight and credibility of Barreto’s testimony. However, at that moment, the Court declined to grant Defendants’ Motion on this ground.

Defendants objected to Barreto’s report, particularly concerning its reliance on partisan exogenous elections, referring to elections other than the type at issue in the pending case. Barreto relied on general partisan elections in Dodge City for state and federal offices. While Courts recognize the limited probative value of analyzing exogenous elections, they also acknowledge their relevance in voting dilution cases, particularly when data on endogenous elections is limited. Defendants failed to identify a Section 2 case where a Court excluded an expert’s opinion solely due to reliance on exogenous elections.

Barreto’s opinion did not rely solely on exogenous elections, but they served as additional support for his conclusion about racially polarized voting in Dodge City. The Court determined that any dispute between experts should be addressed at trial, where the Court could weigh the significance of this additional analysis. Consequently, the Court denied Defendants’ Motion on this ground.

Finally, Defendants sought to exclude Barreto based on bias, contending that his involvement in the case from its origin as a class project at UCLA and the association with the UCLA Voting Rights Project raised questions about his impartiality. The Court acknowledged that expert bias goes to the weight, not the admissibility, of testimony and should be addressed through cross-examination. While recognizing the suspicious circumstances regarding Barreto’s involvement, the Court declined to bar him from testifying solely based on bias, emphasizing the lack of concrete evidence indicating that he sought employment or had preconceived notions. Therefore, the Court decided not to exclude Barreto on the grounds of bias.

Next, the Defendants contested Rubén Martinez’s qualifications as an expert in the case, noting his lack of prior experience with Dodge City history, Kansas history, or the Voting Rights Act. Moreover, Martinez, being a sociologist and not a historian, was a matter of concern for the Defendants, given his opinions on the history of official discrimination in Dodge City and Kansas, as well as the historical background of the at-large election method in Dodge City and Kansas.

For an expert to qualify in a particular field, they must possess skill, experience, or knowledge in that specific area, or the subject must fall within the reasonable confines of their expertise. In this case, both parties acknowledged that Martinez lacked skill, experience, or knowledge in the specific field of voting rights and Kansas history. The dispute centered on whether these issues fell within the reasonable confines of Martinez’s expertise as a political sociologist.

The case primarily revolves around racial discrimination, particularly in a historical and sociopolitical context, which aligns with Martinez’s expertise. While Martinez lacked prior experience with Dodge City or voting rights cases, the Court noted that Defendants did not provide any analogous cases demonstrating that this specific expertise disables him to offer helpful testimony after studying Dodge City’s history for this case. Consequently, the Court denied Defendants’ Motion on these grounds.

The majority of Defendants’ Motion highlights Martinez’s reliance on secondary sources instead of conducting his own research or possessing prior knowledge. However, Defendants did not cite any case where a Court deemed an expert opinion based solely on secondary sources inadequate as a matter of law. Federal caselaw, instead, recognizes that an expert witness can express an opinion based on hearsay sources, including secondary sources. Martinez’s heavy reliance on secondary sources was considered by the Court as affecting the persuasive value of his testimony rather than rendering it inadmissible. The Court determined that the impact of this reliance could be best assessed during the trial, and consequently, it decided not to exclude Martinez’s testimony on this basis.

Defendants contested portions of Martinez’s report, asserting that they lacked sufficient data to support his opinion. Specifically, concerns were raised about Martinez’s personal observations made during his two-day trip to Dodge City, where he informally interviewed one person and drove around the city. For example:- Martinez opined in paragraph 3.22 that housing in Dodge City was highly segregated, based solely on his observations. During his deposition, he admitted not reviewing census data or demographic information and couldn’t explain how he visually identified racially compact housing. The Court deemed such unsupported conclusions about racially segregated housing to fall short of Daubert’s reliability standards, leading to the exclusion of the last sentence of paragraph 3.22.

Likewise, paragraph 3.19 in Martinez’s report detailed an informal interview with a Dodge City resident from Zacatecas, Mexico, who complained about the City not paving the brick streets in his neighborhood. However, Martinez included this information without clarity on its relevance or the resident’s identity. During his deposition, Martinez acknowledged that the individual’s complaint was not evidence of official discrimination. The Court found this information irrelevant to the history of race relations in Dodge City and, as it fell outside the scope of Martinez’s testimony.  Perhaps realizing this, Plaintiffs chose not to respond to Defendants’ argument on this point. Thus, the Court excluded paragraph 3.19 in its entirety. 

The Court issued its rulings on the motions, granting in part and denying in part both Defendants’ Motion to Exclude Matthew Barreto and Defendants’ Motion to Exclude Ruben Martinez. The Court has not arrived on an outcome for this case since the remaining issues involved in this case still await resolution.

This case demonstrates important considerations regarding the admissibility of expert witness testimony. First, the qualifications of the expert must match the subject matter in the case. General expertise may be sufficient if it reasonably aligns with the issues presented. Second, the principles and methodology used by the expert must be reliable as assessed under Daubert.  

Additionally, sample size matters when applying techniques like homogeneous precinct analysis. If the data is too limited, the results might not assist the trier of fact. However, ecological inference may produce helpful opinions even from small data sets. Experts may also rely exclusively on secondary sources, but this affects credibility. Finally, personal observations by the expert must contain adequate factual detail connecting them to an issue in the case. Conclusory or vague observations lack evidence of reliability.  

Overall, this case shows that expert testimony requires both methodological rigor regarding the subject matter as well as factual support for any case-specific opinions. Assumptions and inferences should be clearly explained in the expert’s report. Gaps in these areas impact admissibility in Court.


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