Vacated and remanded by published opinion. Judge DUNCAN wrote the opinion, in which Judge KING and Judge KEELEY joined.
OPINION
This appeal arises from a district court’s order holding that the school board election system of Lexington County, South Carolina, violates Section 2 of the Voting Rights Act of 1965, 42 U.S.C. § 1973 (“Section 2”). Appellant Lexington County School District Three Board of Trustees (the “School Board”) argues that the district court erred in its analysis by considering only the elections that took place between 1994 and 2004, and by misapplying the factors set forth by the Supreme Court in
Thornburg v. Gingles,
I.
Lexington County Schoоl District Three (the “District”) is one of five school districts in Lexington County, South Carolina. It lies primarily within Lexington County, but also includes a small portion of neighboring Saluda County. The District is small: based on the 2000 Census, the total population of the District is only 12,807 persons. African-Americans constitute 28.5 percent of the population and approximately 22 percent of registered voters. The District educates roughly 2,100 students, about 40 percent of whom are minorities.
Before 1978, the School Board members were appointed by the Lexington County Board of Education. But pursuant to a 1978 referendum vote, the District established a seven-member School Board, electеd in at-large, 1 nonpartisan elections *712 held in the last week of February of each year. School Board members were elected to staggered, four-year terms, with two seats elected in three of every four years, and the remaining seat elected in the fourth. Under this electoral system, three African-American individuals were elected to the School Board from 1978 through 1993.
In 1994, the District’s method of electing School Board members changed again. Under this new system, which continues to the present day, School Board members are elected in nonpartisan, at-large elections held during the November general election in even-numbered years. Four seats are еlected in presidential years and three seats are elected in non-presidential even years. Since this change, voter turnout has quadrupled. Voter turnout among Whites, however, has outpaced voter turnout among African-Americans.
On September 29, 2003, R.O. Levy, Betty A. Etheredge, and Shirley W. Barr 2 (collectively, “Plaintiffs”) filed an action against the School Board, its individual members, and Elton Wilson in his official capacity as Chair of the Lexington County Registration and Election Commission. Plaintiffs alleged that the current School Board election process dilutes the voting strength of African-American voters in violation of Section 2. They explained that because of the new system, “[c]andidates for the [School Board] preferred by African Americans are usually defeated by the white majority voting as a bloc.” J.A. 18.
This case went to a bench trial on December 5, 2005. After two days of testimony, the trial was recessed until March 8, 2006. At trial, Plaintiffs showed that from 1994 through 2003, nine African-American candidates ran for the School Board but none were elected. Although they conceded that one African-American candidate, Cora Lester, was elected to the School Board in 2004, Plaintiffs argued that the School Board encouraged her candidacy after this action was filed in order to thwart their Section 2 challеnge. The trial ended on March 10, 2006.
The district court took this matter under advisement for three years. During that time, two School Board elections were held in 2006 and 2008. In the 2008 election, an African-American candidate named Leon Drafts was elected. Given his success, on January 21, 2009, the School Board filed a motion for leave to supplement the record with the 2008 election results.
On February 19, 2009, and without first deciding the School Board’s motion to supplement, the district court issued its judgment on the merits (the “Order”). The district court explained that, based on “information up to and including the 2004 election,” it determined that the School Board electoral system adopted in 1994 violates Section 2. J.A. 731. This appealed followed. 3
II.
Section 2(a) of the Voting Rights Act of 1965 prohibits a state or its political subdivisions from imposing any electoral procedure or practice “in a manner which results in a denial or abridgement of the right of any citizen of the United States to *713 vote on account of race or color.” 42 U.S.C. § 1973(a). Section 2(b) of the Act, as amended in 1982, further provides that a violation of Section 2 occurs
if, based on the totality of circumstances, it is shown that the political processes leading to nomination or election in the State or political subdivision are not equally open to participation by members of a class of citizens protected by subsection (a) of this section in that its members have less opportunity than other members of the electorate to participate in the political process and to elect representatives of their choice.
42 U.S.C. § 1973(b). This means that, where Whites have a majority, minority members have less opportunity than other members of the electorate to participate in the political process and to elect representatives of their choice if the White majority votes sufficiently as a bloc to defeat the minority’s preferred candidates.
See Gingles,
In
Gingles,
the Supreme Court explained that three preconditions must be established for any Section 2 violation. First, “the minority group must be able to demonstrate that it is sufficiently large and geographically compact to constitute a majority in a single-member district.”
Id.
at 50,
“If these preconditions are met, the court must then determine under the ‘totality of circumstances’ whether there has been a violation of Section 2.”
Lewis v. Alamance County, N.C.,
*714 In the case before us, the School Board alleges several errors below. It argues that the district court erred by considering only the elections that took place between 1994 and 2004. It further argues that the district court’s application of the second and third Gingles factors was based on factual and legal errors. 6 We discuss each argument in turn. 7
A.
We first review the School Board’s contention that the district court wrongly limited its analysis to elections that took place between 1994 and 2004. The School Board insists that the district court should have allowed into the record the results from the 2006 and 2008 elections. As noted above, although the School Board moved to supplement the record with the 2008 election results after the case had been submitted for decision, the district court denied this motion in a paperless order almost two months after issuing the Order. In doing so, the court gave only this explanation: “[T]he interests of justice are best served by closing the record.” J.A. 14. The School Board then moved for reconsideration, asking the court to consider both the 2006 and the 2008 elections. The court denied that motiоn as well.
It is within the district court’s discretion to reopen a case to admit new evidence.
8
See Dent v. Beazer Materials and Servs., Inc.,
We are persuaded that the district court’s failure to consider the 2006 and 2008 election results in the Order “work[ed] an ‘injustice’ in the particular circumstances.”
9
Id.
Those electoral results are important and probative given that an African-American candidate was elected to the School Board in 2008. In addition, the School Board had a bona fide explanation for failing to introduce this evidence earlier: such evidence was not available until after the bench trial concluded. Finally, although we are sympathetic to Plaintiffs’ wish to have this case resolved sooner rather than later, we find that concern counterbalanced by the district court’s delay of almost three years in issuing the Order. Because of that delay, two more relevant elections occurred; on such facts, we cannot say Plaintiffs still retain the same interest in a timely disposition as they would have had before the 2006 election. Thus, reopening the case here will cause no undue prejudice to Plaintiffs, so long as they are afforded an opportunity to test and rebut the evidence presented by the School Board.
See Collins II,
*716 B.
Because we are remanding the case, we will address other issues raised on appeal that are likely to recur.
See Elm Grove Coal Co. v. Dir., O.W.C.P.,
1.
We first consider whether the district court erred in its analysis of the third
Gingles
factor.
11
Under this factor, the court must determine whether the majority votes as a bloc to enable it to usually defeat the minority’s preferred candidate.
Gingles,
a.
First, the School Board challenges the method that the district court employed to determine whether a candidate who received less support from minority voters than an unsuccessful first choice may nevertheless be deemed a minority-preferred candidate of choice in a multi-seat election. Pursuant to Lewis,
if the unsuccessful candidate who was the first choice among minority voters did not receive a “significantly higher percentage” of the minority community’s support than did other candidates who also received a majority among minority voters, ... then the latter should also be viewed by the district court as minority-preferred candidates.
In the Order, the district court defined this term based on
Collins II,
We disagree with the district court’s reasoning. Although a 15-percent-age-point differential may be the appropriate standard, it is not necessarily so. Interpreting analogous language,
Lewis
explained that “[t]he level of support that may properly be deemed ‘substantial’ will vary, of course, depending on the number of candidatеs on the ballot and the number of seats to be filled.”
b.
Next, the School Board argues that the district court, in applying the third Gingles factor, erred by assuming that no minority-preferred candidates of choice can come from an election in which no candidate received a majority of the minority vote. The district court reached this conclusion after determining that neither Lewis nor Collins II establishes a construct for analyzing elections in which no candidate received a majority of the minority vote. Accordingly, the district court concluded that the 2002 election was devoid of minority-preferred candidates of choice because “no candidate received a majority of the black vote” during that election. J.A. 754-55.
The district court’s reasoning assumes that a person without support from over 50 percent of minority voters cannot be deemed a minority-preferred candidate.
Lewis,
however, said the opposite: “[W]e do not believe that the mere failure to achieve a threshold of 50% in a multi-candidate election necessarily means that a candidate cannot be viewed as a black-preferred candidate.”
[candidates who receive less than 50% of the minority vote, but who would have been elected had the election been held only among black voters, are presumed also to be minority-preferred candidates, although an individualized assessment should be made in order to confirm that such a candidate may appropriately be so considered.
Id. at 614.
If such candidates can be considered minority-preferred candidates of
*718
choice in an election in which the top vote-getter received more than 50 percent of the vote, we see no reason why a similarly popular candidate — one that would have been elected had the election been held only among African-American voters— should not also be considered a minority-preferred candidate of choice in an election in which no candidate received 50 percent or more of the minority vote.
13
See, e.g., Ruiz v. City of Santa Maria,
c.
Finally, the School Board contends the district court erred in adopting Plaintiffs’ expert’s report over their own expert’s report to ascertain the minority-preferred candidates of choice. To determine which candidates were minority preferred, Plaintiffs’ expert, Dr. John Ruoff, analyzed elections for the School Board from 1986 to 2004 using three statistical methods of analysis: homogenous precinct, ecological regrеssion, and ecological inference. The School Board’s expert, Dr. David Epstein, analyzed the same data using the ecological inference method. Ruoff concluded that there were eight minority-preferred candidates of choice for the School Board between 1994 and 2004. Of those eight, one was elected to the School Board. By contrast, Epstein concluded that there were seventeen minority-preferred candidates of choice during that period. Of those seventeen, six were elected to the School Board.
The district court favored Ruoff s results over Epstein’s, but its reasons for this selection are unclear. 15 The district court explained its choice, in total, as follows:
The court finds more reliable Dr. Ruoff s use of three statistical methods of analysis — homogenous precinct (HP), ecological regression (ER), and ecological inference (ED — as compared to Dr. Epstein’s analysis utilizing only the El method of analysis. The court also finds persuasive Dr. Ruoff s explanations regarding the Ridge Road precinct. 16 The court *719 [thus] adopts Dr. Ruoffs statistical analysis.
J.A. 755-56 (footnote call number added).
We recognize that our role in reviewing the district court’s reliance on Ruoffs expert testimony is limited.
In re Corrugated Container Antitrust Litig.,
The district court failed to acknowledge or explain what appear, on review, to be the limitations of Ruoffs report. Although “absolute perfection on the base statistical data is not to be expected, a trial court should not ignore the imperfections of the data used nor the limitations of statistical analysis.”
Overton v. City of Austin,
For these reasons, while we do not necessarily agree with the School Board that the district court erred in adopting Ruoffs report, we also cannot say with certainty that the district court properly adopted Ruoffs expert report in its candidate-of-choice analysis. 17
2.
We next consider the School Board’s contention that the district court’s approach to the second
Gingles
factor rests on error. Under the second
Gingles
factor, to determine whether a minority group is politically cohesive, a court must ascertain whether “a significant number of
*720
minority group members usually vote for the same candidates.”
Gingles,
First, the School Board contends that the district court erred in its political cohesiveness analysis by only considering minority support for candidates which the court had already classified as minority-preferred candidates of choice. We agree. Given the district court’s assumption that a minority-preferred candidate of choice needed to have over 50 percent of minority support, the court’s approach logically guaranteed a finding of cohesiveness. 18
Second, the School Board contends that the district court wrongly equated political cohesiveness with racial polarization, i.e., the tendency for voters to prefer candidates of their same race, by emphasizing that “[e]ach of these candidates is black.” J.A. 739. We note that, although the existence of racially polarized voting can establish that the minority group is politically cohesive,
see Collins I,
III.
For the foregoing reasons, we vacate the district court’s February 19, 2009 order, and remand for further proceedings. The outstanding motions are denied as moot.
VACATED AND REMANDED
Notes
. Under at-large electoral systems, "a group of candidates is placed on the ballot to fill a designated number of seats, and voters from everywhere within the jurisdiction may vote to fill those seats.” Steven J. Mulroy, The Way Out: A Legal Standard for Imposing Alternative Electoral Systems аs Voting Rights Remedies, 33 Harv. C.R.-C.L. L.Rev. 333, 336 *712 (1998). "The traditional winner-take-all form of at-large elections allows each voter to cast only one vote for each candidate, up to the number of available seats.” Id.
. Barr was dismissed as a party on September 28, 2004.
. Later, on April 17, 2009, the district court denied the School Board's motion to supplement. The court also denied a subsequent motion for reconsideration.
.Those factors are:
1. the extent of any history of official discrimination in the state or political subdivision that touched the right of the members of the minority group to register, to vote, or otherwise to participate in the democratic process;
2. the extent to which voting in the elections of the state оr political subdivision is racially polarized;
3. the extent to which the state or political subdivision has used unusually large election districts, majority vote requirements, anti-single-shot provisions, or other voting practices or procedures that may enhance the opportunity for discrimination against the minority group;
4. if there is a candidate slating process, whether the members of the minority group have been denied access to that process;
5. the extent to which members of the minority group in the state or political subdivision bear the effects of discrimination in such areas as education, employment and health, which hinder their ability to рarticipate effectively in the political process;
6. whether political campaigns have been characterized by overt or subtle racial appeals; and
7. the extent to which members of the minority group have been elected to public office in the jurisdiction.
[8.] whether there is a significant lack of responsiveness on the part of elected officials to the particularized needs of the members of the minority group[; and]
[9.] whether the policy underlying the state or political subdivision's use of such voting qualification, prerequisite to voting, or standard, practice or procedure is tenuous.
S.Rep. No. 417, 97th Cong., 2d Sess. 28-29,
reprinted in
1982 U.S.Code Cong. & Admin. News 177, 206-07 (footnote call numbers
*714
omitted) (cited in
Collins v. City of Norfolk, Va. ("Collins II"),
. We recognize that
Collins v. City of Norfolk, Va.,
. At a hearing held on September 9, 2004, the district court held that Plaintiffs had established the first Gingles factor, so its analysis in the Order focused solely on the second and third factors.
. The School Board also contends that the district court, in its totality of the circumstances analysis, (1) failed to consider unre-butted evidence in the record showing that minority candidates lost for reasons other than White bloc voting; (2) improperly discounted the post-litigation election of Cora Lester in 2004 due to "special circumstances”; and (3) failed to consider substantial record evidence as to the Senate Report factors that supports the rejection of Plaintiffs’ claim. Because we remand on other bases, we do not find it necessary to address these arguments.
.The School Board did not seek to reopen the case but instead moved to supplement the record. To allow one side to supplement the record without allowing the opposing party the opportunity to contest the admissibility, reliability, and accuracy of the new evidence, and to offer rebuttal evidence, would implicate due process concerns.
See, e.g., Greene v. McElroy,
. Although the School Board only moved to introduce the results of the 2008 election, we agree with the district court’s holding that “the 2008 school board election results would be of little benefit to the court absent the inclusion of the relevant information from both the 2006 and the 2008 elections in the expert analysis.” J.A. 14.
. The School Board also argues that the district court should have considered the results from the 1980-1993 elections. Although we remand for further consideration of the 2006 and 2008 elections, the district court is not required to consider the pre-1994 elections. The complaint challenged only the present voting system, and "[ejections held under a significantly different electoral structure” are less probative in a Section 2 analysis.
See NAACP v. City of Niagara Falls, N.Y.,
Still, the School Board makes much of the fact that the district court only considered six elections in its analysis, and thus argues that, pursuant to our holding in
Lewis
and the Second Circuit’s in
Niagara Falls,
the district court should have considеred the results from the 1980-1993 elections. Neither
Lewis
nor
Niagara Falls
specifies how many elections a court must review to analyze a Section 2 violation.
Lewis
declined to set a bright-line standard and chose to "leave to another day the question of precisely how many elections must be considered in order for a district court’s conclusions to be adequately supported.”
. We address the third
Gingles
factor before the second because doing so makes for ease of analysis in this case. The factors are conjunctive, but there is no requirement that we analyze them in alphanumerical order.
See, e.g., Voinovich v. Quilter,
. We recognize that in
Collins II,
just as here, voters filled either three or four seats each election, depending on the year.
. Under this construct, for example, William Berry and Stephen Padgett, the top minority vote-getters in 2002 with 48 percent of the African-American vote, could potentially be classified as minority-preferred candidates of choice if an individualized assessment supports that conclusion.
. In those circumstances, the district court should ensure that the candidate can be fairly considered a representative of the minority cоmmunity. In addition to the bare statistics, the district court may consider testimony from political observers and the candidates themselves to determine whether those candidates may be labeled minority-preferred candidates of choice. See
Collins II,
. The School Board suggests that the district court preferred Ruoff's data over Epstein’s because Epstein “changed his definition of candidate of choice significantly during the course of litigation.” J.A. 752. This argument is without merit. After finding Epstein had changed his definition of candidate of choice several times, the district court rejected Epstein’s definition for "minority-preferred candidate of choice,” not his data altogether.
.Ruoff explained that Ridge Road, a particularly large, overwhelmingly White precinct, was an outlier and thus required special treatment. At the time of the 2004 election, Ridge Road contained 1,087 voters, only 22 (2 percent) of whom were African-American. Ruoff opined that, since the Ridge Road precinct overwhelmingly consists of White voters, including this precinct in the regression analysis would have overestimated the percent of African-American votes in favor of *719 minority-preferred candidates. Rather than simply discarding the votes from the Ridge Road precinct, Ruoff added them back into the analysis after sepаrately completing the ecological regression and ecological inference estimates for the remaining precincts.
. This is of particular concern given that had the district court preferred Epstein's data over Ruoffs, the results of this case would likely have been very different.
. For example, the district court determined that no minority-preferred candidates of choice existed in the 2002 election because no candidate during that election achieved more than 50 percent of the minority vote. Thus, in its political cohesiveness analysis, the district court did not consider the 2002 electoral results. Yet, the 2002 results presumably demonstrate a lack of political cohesiveness— the very factor the district court sought to establish under the second Gingles factor.
. It is not necessary to prove racial polarization in order to find political cohesiveness. As this court noted in
Lewis,
"to our knowledge, no court has held that a white candidate cannot, as a matter of law, be a minority-preferred candidate.”
. In addition, we note that in reviewing the level of support received by minority-preferred candidates of choice in the various elections, the district court failed to note the level of support African-Americans gave to other candidates during those elections.
See Monroe,
