OPINION
Appellant 3M Company challenges the district court’s certification of a class of more than 4,900 current and former 3M employees in this age-discrimination action brought under the Minnesota Human Rights Act (MHRA), Minn.Stat. §§ 363A.01-.41 (2008). Because we conclude that the district court did not properly apply the standards for certification under Minnesota Rule of Civil Procedure 23, we reverse and remand for further proceedings consistent with this opinion.
FACTS
Respondents, five current and former 3M employees, initiated this action against 3M in 2004, asserting that, since at least as early as 2001, 3M has engaged in a pattern and practice of age discrimination in employment in violation of the MHRA. See Minn.Stat. § 363A.08, subd. 2. Respondents alleged intentional discrimination in five areas: performance appraisals, selection for training programs, promotions, compensation, and terminations. In the alternative to their intentional-discrimination allegations, respondents asserted that 3M maintained neutral policies in these five areas that had a disparate impact on older employees. , See MinmStat. § 363A.28, subd. 10. Respondents asserted all of their claims on behalf of themselves and others similarly situated.
In November 2007, respondents moved for class certification pursuant to rule 23 of the Minnesota Rules of Civil Procedure. In support of their motion for certification, respondents relied on the expert opinion of *634 Dr. Janet R. Thornton. Based on a combination of multiple regression, pools (or selection), and logistic regression analyses, Thornton opined that there were statistically significant disparities in the treatment of 3M employees under the age of 46 versus those 46 and older in each of the five areas. In conducting her analyses, Thornton controlled for various organizational and employee characteristics, including employee grade. In the four areas other than performance evaluations, Thornton conducted analyses both with and without performance-related controls, although none of her analyses regressed for all available performance controls. Thornton defended the exclusion of performance measures as a control because she found age disparities in those measures and concluded that they potentially were “tainted” by age discrimination. Thornton’s analyses were “cross-sectional” in that they examined employment events at certain points in time.
3M opposed respondents’ motion for class certification with its own experts. Dr. Bernard Siskin opined generally that age discrimination is difficult to identify statistically because of negative correlations within grade levels between age and “speed of success,” performance, and potential. In other words, Siskin opined that one would expect performance, potential, rate of promotion, and the rate of pay increases to decline as an employee ages, even absent any age discrimination. Sis-kin conducted an alternative, longitudinal analysis, which assessed trends in compensation and promotion rates, and concluded that those trends were consistent over time and thus inconsistent with the initiation of a pattern and practice of age discrimination beginning in 2001, as respondents alleged.
Siskin further criticized Thornton’s cross-sectional analyses, opining that they fail to account for performance and related relevant variables. Siskin asserted that the disparities in performance measures observed by Thornton do not demonstrate age discrimination; that Thornton essentially assumed that they did; and that, based on that flawed assumption, Thornton excluded performance controls from most of her analyses and did not use all available measures in any of her analyses. Sis-kin conducted his own cross-sectional anal-yses controlling for available performance measures and found that disparities either ran in favor of older employees, or that there was no statistically significant disparity.
3M also submitted a report from labor economist Robert Topel, who opined that Thornton’s analyses revealed no more than expected and documented trends in the labor market and did not provide a basis for concluding that observed disparities were the result of age discrimination.
Thornton responded to Siskin’s report, opining that his longitudinal analysis failed to control for factors that he had identified as key to the regression analyses and that his regression analyses included factors not supported by 3M documentation, and generally reinforcing her original report. Respondents also submitted a rebuttal report from David Neumark, another labor economist, who opined that Topel and Sis-kin overstated the extent to which established labor trends explained the statistical disparities observed by Thornton.
The district court granted respondents’ class-certification motion. In its discussion regarding the commonality requirement of Minn. R. Civ. P. 23.01(b), the district court acknowledged the dispute among the experts regarding the significance of the various statistical analyses, but declined to resolve the dispute. The court explained that:
[Respondents] have presented statistical evidence that strongly suggests a consistent pattern across 3M’s business units *635 of disparities suffered by older employees in each of the human resource practices challenged. Although 3M disputes the analysis conducted by [respondents’] expert, the court finds that sufficient statistical evidence has been presented to suggest that the data presents common questions for a class-wide pattern or practice trial.
Finding that each of the requirements of rule 23.01 was met and that class treatment was appropriate under Minn. R. Civ. P. 23.02(b) and (c), the district court certified a class of “[a]ll persons who were 46 or older when employed by 3M in Minnesota in a salaried exempt position below PS grade 180 at any time on or after May 10, 2003, and who did not sign a [release].”
3M petitioned this court for discretionary review of the district court’s certification decision. We granted that petition based on our conclusion that the district court’s rule 23 analysis was questionable, in light of federal precedent; that review would serve judicial economy; and that the case presented issues of statewide significance such that a decision in this case could provide important guidance for the Minnesota bench and bar.
ISSUES
I. What standard of review applies to a district court decision on a motion for class certification?
II. Did the district court err by failing to require respondents to prove the certification requirements of rule 23 by a preponderance of the evidence?
III. Did the district court err by failing to resolve factual disputes among the parties’ experts?
ANALYSIS
I
Class certification decisions by Minnesota district courts are governed by rule 23 of the Minnesota Rules of Civil Procedure. A certifiable class must meet all of the elements of rule 23.01 — numerosity, commonality, typicality, and adequacy of representation — and one of the sections of rule 23.02.
Lewy 1990 Trust ex rel. Lewy v. Inv. Advisors, Inc.,
Although Minnesota courts have not expressly articulated a standard of review, it is clear that our review of the district court’s certification decision should be for abuse of discretion.
See Gordon v. Microsoft Corp.,
3M resists application of the abuse-of-discretion standard, arguing that de novo review should apply because the district court’s certification order is based on
*636
an erroneous interpretation of the law. However, as 3M acknowledges, it is an abuse of discretion when the district court improperly applies the law.
See St. Jude,
An abuse occurs when a court, in making a discretionary ruling, relies upon an improper factor, omits consideration of a factor entitled to substantial weight, or mulls the correct mix of factors but makes a clear error of judgment in assaying them. An abuse of discretion also occurs if the court adopts an incorrect legal rule.
In re New Motor Vehicles Canadian Exp. Antitrust Litig.,
Thus, we proceed to examine the district court’s certification decision under an abuse-of-discretion standard, mindful of the various forms that such an abuse may take.
II
3M asserts that the district court erred by failing to require proof of rule 23 certification requirements by a preponderance of the evidence and by failing to resolve factual disputes relevant to the class-certification requirements. While neither this court nor the Minnesota Supreme Court has addressed the standard of proof to be applied to rule 23 requirements, 3M relies on federal caselaw applying a preponderance standard.
See, e.g., Teamsters Local 445 Freight Div. Pension Fund v. Bombardier, Inc.,
*637
The federal courts have also held that the factual disputes requiring resolution by the district court at the class-certification stage can include disputes that are the subject of expert testimony. As the Third Circuit recently explained, “[e]xpert opinion with respect to class certification, like any matter relevant to a Rule 23 requirement, calls for rigorous analysis.”
In re Hydrogen Peroxide Antitrust Litig. (Hydrogen Peroxide),
[a] district [court] may not duck hard questions by observing that each side has some support, or that considerations relevant to class certification also may affect the decision on the merits. Tough questions must be faced and squarely decided, if necessary by holding eviden-tiary hearings and choosing between competing perspectives.
Id.
These federal cases resolve a longstanding tension between class certification and the merits stemming from seemingly contradictory language in two U.S. Supreme Court decisions. In
Eisen v. Carlisle & Jacquelin,
the Court explained that “nothing in either the language or history of Rule 23 ... gives a court any authority to conduct a preliminary inquiry into the merits of a suit in order to determine whether it may be maintained as a class action.”
the class determination generally involves considerations that are enmeshed in the factual and legal issues comprising the plaintiffs cause of action. Sometimes the issues are plain enough from the pleadings to determine whether the interests of absent parties are fairly encompassed with the named plaintiffs claims, and sometimes it may be necessary for the court to probe behind the pleadings before coming to rest on the certification question.... [A]dual, not presumed, conformance with Rule 23(a) remains, however, indispensable.
*638
The federal courts of appeal have addressed expert testimony related to class certification primarily in two contexts: securities litigation and antitrust litigation. In the securities context, the modern trend is to preclude certification of claims based on fraud on the market unless the district court concludes that the market is efficient — an issue that is typically the subject of competing expert opinions — and thus that the plaintiffs will be entitled to a presumption of reliance.
See, e.g., IPOS,
In the antitrust context, the modern trend precludes certification unless the court concludes that the antitrust-impact element can be proven by common evidence, an issue that is usually the subject of expert testimony.
See Hydrogen Peroxide, 552
F.3d at 327,
We find the federal caselaw persuasive and conclude that the certification requirements of Minnesota’s rule 23 — like those of its federal counterpart — must be established by a preponderance of the evidence. We further hold that the preponderance standard requires the district court to resolve factual disputes relevant to rule 23 certification requirements, including relevant expert disputes. We note that the factual findings at the class-certification stage are not binding on the ultimate trier of fact.
Gariety,
Having identified the appropriate standards to be applied under rule 23, we next determine whether the district court’s decision complied with these standards in this ease.
Ill
Because the “nature of the evidence that will suffice to resolve a question determines whether the question is common or individual,” courts must analyze rule 23 certification requirements with specific reference to the cause of action asserted in a particular ease.
Blades,
Respondents assert two theories of discrimination, each of which is proved using statistics. To prove their pattern-or-practice claim, a claim of intentional discrimination, respondents must show that age discrimination was 3M’s “standard operating procedure — the regular rather than the unusual practice.”
Intern. Broth. of Teamsters v. United States,
Statistics are relevant not only to the merits of respondents’ claims, but to certification as well. This is because, in order to proceed as a class, respondents must bridge the gap between their individual claims of discrimination and the existence of a class of similarly situated employees.
See Falcon,
We conclude that the district court erred in its certification analysis, both by failing to require proof of rule 23 certification requirements by a preponderance of the evidence and by failing to resolve factual disputes relevant to class-certification requirements. While the district court considered respondents’ statistical analy-ses as relevant to the class-certification decision, it declined to address 3M’s objections to those statistics or 3M’s alternative statistical analyses. The standards that we adopt from the federal caselaw require the district court to resolve the differences among the experts to the extent that they are relevant to, and for the limited purposes of, determining whether class-certification requirements were met. In particular, the district court, using the preponderance-of-the-evidence standard, must address and decide all of the alleged defects in respondents’ expert-witness testimony relating to the rule 23 requirements of numerosity, commonality, typicality, and predominance. This means that the district court must determine the validity and weight of 3M’s concerns with demonstrating a baseline of expected, non-discriminating differences, bridging the gap between individual claims of discrimination and the existence of a class of similarly situated employees, selected problems with doing a “snap-shot” analysis, and the alleged inappropriate use of certain statistical controls for the predicted non-discriminatory correlation between age and employment outcomes.
Respondents assert that the holdings in the antitrust and securities cases should not apply in the context of their age-discrimination claims, attempting to distinguish the former as cases involving legal issues rather than factual disputes.
See Hnot v. Willis Group Holdings Ltd.,
Respondents further urge this court to adopt the analysis of the federal district court in
Hnot,
that the determination of the
existence
of common questions can be separated from finding the
answer
to those questions.
See
In sum, we conclude that parties moving for class certification under Minn. R. Civ. P. 23 must prove, by a preponderance of the evidence, that the certification requirements of the rule are met. This means that district courts must address and resolve factual disputes relevant to class-certification requirements, including disputes among expert witnesses. Because the district court failed to apply the appropriate standards, we reverse and remand for the district court’s reconsideration of the class-certification motion.
1
On remand, the district court, in its discretion, may elect to re-open the record and accept additional evidence.
See IPOS,
DECISION
Because the district court failed to require proof of rule 23 certification requirements by a preponderance of the evidence and failed to resolve factual disputes relevant to rule 23 certification requirements, we reverse and remand for further proceedings consistent with this opinion.
Reversed and remanded.
Notes
. 3M urges this court to hold that certification is not available under rule 23 on the facts of this case. We decline to do so because our role as an error-correcting court does not extend to making factual findings in the first instance. See
Sefkow v. Sefkow,
