Court Opinion

ID: 9522780
Source: CourtListenerOpinion
Date Created: 2023-08-07 02:32:16.708125+00
Date Added: 2024-06-11T13:03:55.508336
License: Public Domain

Skoghmd, J.
¶ 1. Claimant appeals from the superior court’s order granting summary judgment to insurer in this workers’ compensation case.1 He argues that the court: (1) exceeded its jurisdiction under 21 V.S.A. § 671 by granting summary judgment to insurer; and (2) abused its discretion by excluding the expert testimony that he offered. We affirm the trial court’s decision.
¶ 2. The trial court found the following facts to be undisputed. Claimant worked for the City of Burlington Fire Department for thirty-six years, first as a firefighter and later as assistant chief. It is not clear if claimant was actively fighting fires throughout his career or if, at some point, he engaged in a combination of administrative work and active duty.
*235¶ 3. In 2003, claimant died of non-Hodgkin’s lymphoma (NHL). His estate brought a workers’ compensation action, alleging that his work as a firefighter caused him to develop NHL. The Vermont Department of Labor denied his claim. The Commissioner ruled that although claimant proved that there was an “association” between NHL and firefighting, he failed to establish a “causal connection” between the general activity of firefighting and NHL. The Commissioner found no evidence as to the number of fires that claimant fought, the level of his participation in those fires, or the number of such fires that were industrial or commercial in nature, where known carcinogens might have been present. There was similarly no evidence as to the frequency of exposure or types of exposures that claimant may have had. Without this information, the Commissioner found that NHL was possibly, but not probably, related to his employment. The Commissioner thus concluded that claimant failed to meet his burden of proof and she denied the claim.
¶4. Claimant appealed this decision to the superior court, and the Commissioner certified the following question for determination: was claimant’s NHL causally related to his work as a firefighter? In August 2007, insurer moved for summary judgment on this question. It asserted that the opinions of claimant’s experts should be excluded under Vermont Rule of Evidence 702 as both irrelevant and scientifically unreliable, and that without any admissible evidence of causation, claimant was not entitled to workers’ compensation benefits.
¶ 5. Claimant responded by moving to strike the motion for summary judgment. He argued that the standard for the admissibility of expert testimony under Rule 702, delineated in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993), and adopted by this Court in State v. Brooks, 162 Vt. 26, 643 A.2d 226 (1993), did not apply to workers’ compensation claims being tried in superior court. He maintained that the trial court was instead bound by the approach taken by the Commissioner, and therefore it was obligated to evaluate the admissibility of the expert testimony using a “plausibility” standard rather than the test set forth in Daubert.2 Claimant also argued that insurer had waived *236its right to challenge the admissibility of the evidence by failing to raise this argument before the Commissioner. Finally, claimant asserted that the court lacked jurisdiction to grant a motion for summary judgment.
¶ 6. The trial court denied claimant’s motion to strike in a written order. It explained that the rules of evidence applied “to all actions and proceedings in the courts of this state,” V.R.E. 1101(a), and that it had no discretion to create a new standard for the admission of expert testimony in workers’ compensation cases. It noted, moreover, that there was nothing in the workers’ compensation statutes that would alter the application of the rules of evidence in such cases. As to claimant’s remaining arguments, the court indicated that its review of the Commissioner’s decision was de novo, and thus, insurer’s failure to raise the Daubert issue below was irrelevant. The court did not directly address the jurisdictional argument.
¶ 7. The court allowed claimant additional time to respond to the merits of the summary judgment motion, and following a hearing, it granted summary judgment to insurer. As discussed in additional detail below, the court found that the expert testimony proffered by claimant did not meet the requirements of Rule 702, and that it was therefore inadmissible. This appeal followed.
¶ 8. We begin with claimant’s procedural arguments. Claimant asserts that insurer could not challenge the admissibility of his expert evidence in the trial court proceedings because (1) it failed to raise this argument before the Commissioner; (2) collateral estoppel precluded the relitigation of this issue; and (3) there was no certified question concerning the admissibility of this evidence. Claimant reiterates his position that the trial court should not have applied the rules of evidence, but rather, that it was obligated to apply the same standard as that employed by the Commissioner. Finally, claimant maintains that the trial court lacked jurisdiction to grant insurer’s motion for summary judgment because its jurisdiction is limited to answering questions of fact or mixed questions of fact and law.
¶ 9. Claimant appears to misunderstand the nature of the review conducted by the trial court. The court’s review of the Commissioner’s decision “involves a retrial de novo.” Farris v. Bryant Grinder Corp./Wausau Ins. Co., 2005 VT 5, ¶ 10, 177 Vt. 456, 869 A.2d 131 (quotation omitted). That means, as the trial *237court found, that insurer is not limited to the arguments raised below, and preservation — or lack thereof — is not at issue.3 The doctrine of collateral estoppel is similarly not relevant here because there has not yet been a final judgment on the merits. Cf. Sheehan v. Dep’t of Employment & Training, 169 Vt. 304, 308, 733 A.2d 88, 91 (1999) (doctrine of collateral estoppel “bars the subsequent relitigation of an issue which was actually litigated and decided in a prior case between the parties resulting in a final judgment on the merits, where that issue was necessary to the resolution of the action” (quotation omitted)).
¶ 10. It is true, as claimant asserts, that the trial court’s jurisdiction in workers’ compensation proceedings is limited to a review of questions of fact or questions of fact and law certified to it by the commissioner. 21 V.S.A. § 671; Roethke v. Jake’s Original Bar & Grill, 172 Vt. 555, 556, 772 A.2d 492, 493 (2001) (mem.). The question certified in this case was one of fact — did claimant’s employment cause his NHL? In the proceedings before the trial court, claimant bore the burden of producing sufficient evidence to support his claim that this question should be answered in the affirmative, and that he was therefore entitled to workers’ compensation benefits. See, e.g., Goodwin v. Fairbanks Morse & Co., 123 Vt. 161, 166, 184 A.2d 220, 223 (1962) (“[T]he burden is on the claimant to establish the facts essential to the right asserted.”).
 ¶ 11. In evaluating this case, the trial court was obligated to apply the rules of evidence and to determine if the expert testimony proffered by claimant was relevant and admissible. See V.R.E. 1101(a) (rules of evidence apply “to all actions and proceedings in the courts of this state”); V.R.E. 104(a) (preliminary questions concerning admissibility of evidence shall be determined by trial court); V.R.E. 402 (evidence that is not relevant is not admissible); 985 Assocs., Ltd. v. Daewoo Elecs. Am., Inc., 2008 VT 14, ¶ 6, 183 Vt. 208, 945 A.2d 381 (trial judges must “act as gatekeepers who screen expert testimony ensuring that it is reliable and helpful to the issue at hand before the jury hears it” *238(quotation omitted)); cf. 21 V.S.A. § 602 (all processes and procedures under provisions of Title 21, chapter 9, shall be as summary and simple as reasonable may be); id. § 604 (Commissioner of Labor not bound by common law or statutory rules of evidence or by technical or formal rules of procedure except as provided in Title 21, chapter 9, and he or she may conduct hearing or trial in such manner as to ascertain substantial rights of parties). The trial court was similarly obligated to apply the rules of civil procedure, including Vermont Rule of Civil Procedure 56. See V.R.C.P. 1 (rules of civil procedure govern procedure in trial courts in all suits of a civil nature, including appeals to the trial court from any department of the state or any political subdivision thereof). Contrary to claimant’s assertion, the court did not need certified questions from the Commissioner to enable it to apply the rules of evidence and civil procedure.
¶ 12. We reject claimant’s suggestion that these rules are somehow inapplicable in workers’ compensation cases heard by the superior court. Claimant cites Crosby v. City of Burlington, 176 Vt. 239, 249-50, 844 A.2d 722, 729-30 (2003), as support for his assertion that the Commissioner’s interpretation of Vermont workers’ compensation law is controlling absent compelling indication of error. We are not addressing the Commissioner’s interpretation of workers’ compensation law here, however; we are considering the applicability of the rules of evidence and civil procedure to proceedings conducted in a trial court. The Commissioner has no expertise in such matters, and no deference to the Commissioner’s approach is required. Cf. In re Cent. Vt. Pub. Serv. Corp., 172 Vt. 14, 19-20, 769 A.2d 668, 673 (2001) (affording no deference to Public Service Board’s decisions on claim preclusion and issue preclusion because application of judicially-created doctrines not within Board’s areas of expertise); In re Duncan, 155 Vt. 402, 408, 584 A.2d 1140, 1144 (1990) (absent compelling indication of error, interpretation of statute by administrative body responsible for its execution will be sustained on appeal).
¶ 13. The fact that insurer was granted judgment as a matter of law in this case does not transform the certified question into one of pure law that must be decided only by this Court. The trial court’s inquiry under Rule 702 was plainly fact-based. And the court merely recognized, following its evidentiary rulings, that claimant failed to identify a triable issue *239of fact, and therefore a trial was unnecessary. See, e.g., Sykas v. Kearns, 135 Vt. 610, 612, 383 A.2d 621, 623 (1978) (function of summary judgment is to avoid a useless trial). As we have explained, “when a party fails, after adequate discovery, to make a showing sufficient to establish an element essential to her case and on which she has the burden of proof, summary judgment is required.” Edson v. Barre Supervisory Union #61, 2007 VT 62, ¶ 8, 182 Vt. 157, 933 A.2d 200. Claimant’s procedural claims are without merit.
¶ 14. We thus turn to the heart of claimant’s appeal — whether the trial court erred in concluding that the expert testimony he offered was inadmissible under Rule 702, and that insurer was therefore entitled to summary judgment in its favor. Rule 702 provides that:
If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert . . . may testify thereto in the form of an opinion or otherwise, if (1) the testimony is based upon sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case.
This rule is intended to create “a flexible standard requiring only that expert testimony be both relevant and reliable to be admissible.” Daewoo, 2008 VT 14, ¶ 6. We review the trial court’s decision to admit or exclude expert testimony for abuse of discretion. Id. ¶ 9. As discussed below, we find no abuse of discretion here.
¶ 15. In reaching our conclusion, we emphasize several fundamental principles. As the United States Supreme Court has recognized, an expert’s “conclusions and methodology are not entirely distinct from one another.” Gen. Elec. Co. v. Joiner, 522 U.S. 136, 146 (1997). Thus, in fulfilling its gatekeeper role, the trial court must “examine the expert’s conclusions in order to determine whether they could reliably flow from the facts known to the expert and the methodology used.” Magistrini v. One Hour Martinizing Dry Cleaning, 180 F. Supp. 2d 584, 595 (D.N.J. 2002) (quotation omitted). Where an expert opinion rests “on nebulous *240methodology,” it is “unhelpful to the trier of fact, [and] it has no place in courts of law.” Valentine v. Conrad, 2006-Ohio-3561, ¶ 18, 850 N.E.2d 683.
¶ 16. We have held that “the trial court’s inquiry into expert testimony should primarily focus on excluding ‘junk science’ — because of its potential to confuse or mislead the trier of fact — rather than serving as a preliminary inquiry into the merits of the case.” Daewoo, 2008 VT 14, ¶ 10. Thus, we have explained that as long as scientific evidence “has a sound factual and methodological basis and is relevant to the issues at hand, it is within the purview of the trier of fact to assess its credibility and determine the weight to be assigned to it.” Id. ¶ 16. At the same time, we are mindful that nothing requires the trial court “to admit opinion evidence that is connected to existing data only by the ipse dixit of the expert,” and the court may properly “conclude that there is simply too great an analytical gap between the data and the opinion proffered.” Joiner, 522 U.S. at 146; see also Daubert, 509 U.S. at 590 (“[I]n order to qualify as ‘scientific knowledge,’ an inference or assertion must be derived by the scientific method.”).
¶ 17. In this case, claimant relied on the testimony of three experts — Dr. Tee Guidotti, Dr. James Lockey, and Dr. Grace LeMasters — to prove that his NHL was causally related to his employment.4 Dr. Guidotti opined that, “within reasonable medical certainty and given the weight of evidence,” claimant’s NHL “arose from his work as a firefighter and was caused by exposures in the course of his occupation as a firefighter.” Dr. Lockey asserted that there was “a reasonable medical probability that [claimant’s] work as a firefighter was the cause of his non-Hodgkin’s lymphoma.” Dr. LeMasters had no opinion as to the specific cause of claimant’s NHL. All three experts relied upon epidemiological studies as the basis for their conclusions.5
*241 ¶ 18. Epidemiology “studies the incidence, distribution and etiology of disease in human populations” with the goal of gaming a better understanding of disease causation and disease prevention in groups of individuals. Magistrini, 180 F. Supp. 2d at 590. To this end,
[e]pidemiological evidence identifies agents that are associated with an increased risk of disease in groups of individuals, quantifies the amount of excess disease that is associated with an agent, and provides a profile of the type of individual who is likely to contract a disease after being exposed to an agent. The focus of epidemiology is on general causation (ie., is the agent in question capable of causing disease?) and not specific causation (ie., did the agent cause a disease in a particular individual?).
Id. (quotation omitted). As the trial court recognized, and as noted above, epidemiological studies can assist in demonstrating a general association between a substance and a disease or condition, but they cannot prove that a substance actually caused a disease or condition in a particular individual. Merrell Dow Pharms., Inc. v. Havner, 953 S.W.2d 706, 715 (Tex. 1997); see also M. Green et al., Reference Guide on Epidemiology, in Reference Manual on Scientific Evidence 333, 381 (Federal Judicial Center ed., 2d ed. 2000), available at http://www.fjc.gov (“Epidemiology is concerned with the incidence of disease in populations and does not address the question of the cause of an individual’s disease. This question, sometimes referred to as specific causation, is beyond the domain of the science of epidemiology.” (footnote omitted)).
¶ 19. Notwithstanding this limitation, numerous courts have considered the role that epidemiological studies can play in estabhshing specific causation. Green, supra, at 382. The existing case law focuses both on the admissibility of epidemiological evidence, as well as whether, and under what circumstances, such evidence could be considered sufficient to meet a plaintiffs burden of production. Id. According to Green, “[a]n epidemiologic study that is sufficiently rigorous to justify a conclusion that is scientifically valid should be admissible, as it tends to make an issue in dispute more or less likely.” Id. As to sufficiency, Green explains that
*242[t]he civil burden of proof is described most often as requiring the fact finder to believe that what is sought to be proved is more likely true than not true. The relative risk from epidemiologic studies can be adapted to this 50% plus standard to yield a probability or likelihood that an agent caused an individual’s disease.
Id. at 383 (quotation omitted).6
¶ 20. With this background in mind, we turn to the nature of epidemiological studies, generally. Epidemiological studies quantify the degree of association between a given substance and disease by assigning a “relative risk” factor to the association.7 c3 c-*243See Hall v. Baxter Healthcare Corp., 947 F. Supp. 1387, 1403 (D. Or. 1996). “When the relative risk reaches 2.0, the risk has doubled, indicating that the risk is twice as high among the exposed group as compared to the non-exposed group.” Magistrini, 180 F. Supp. 2d at 591. Thus, “the threshold for concluding that an agent was more likely than not the cause of an individual’s disease is a relative risk greater than 2.0.” Id. (quotation omitted). The trial court here adopted a relative risk factor of 2.0 as a benchmark, finding that it easily tied into Vermont’s “more likely than not” civil standard and that such a benchmark was helpful in this case because the eight epidemiological studies relied upon by claimant’s experts reflected widely varying degrees of relative risk.
¶ 21. The trial court found that only two of the eight epidemiological studies relied upon by the experts in this case reflected a relative risk greater than 2.0 — Figgs and Sama — while the remaining six showed “little or no association” between firefighting and lymphomas. Notwithstanding the results of these studies, Dr. Guidotti opined that firefighting was in fact what caused claimant’s lymphoma. Other than an undefined reference to “weight-of-the-evidence methodology,” however, the court could not discern the scientific method that Dr. Guidotti used to reach his conclusion. The court also noted that the studies that Dr. Guidotti relied upon may have been overinclusive, reflecting associations between other types of lymphomas and generic cancers in firefighters.8 For these reasons, the court could not find that Dr. Guidotti’s testimony was based upon sufficient facts or data or that he applied the principles of epidemiological analysis reliably to this case. See V.R.E. 702(1), (3).
¶ 22. The court was equally unpersuaded by the “meta-analysis” conducted by Dr. Lockey and Dr. LeMasters. See Knight v. Kirby Inland Marine, Inc., 363 F. Supp. 2d 859, 866 n.13 (N.D. Miss. 2005) (explaining that meta-analysis is a technique that “pools the results of multiple studies to arrive at a single figure representative of all of the studies reviewed”). The court found that these doctors used a similarly-undefined “weight-of-the-evidence” approach to attempt to demonstrate a general association between *244firefighting and NHL. They failed to make their analysis accessible to the court, however, and the court consequently found it impossible to conclude that the meta-analysis was a reliable scientific method, reproducible by others in the field, and not specifically done for the purpose of this litigation, to counter the various studies’ inherent contradictions with respect to relative risk.
¶ 23. The court also found that of the thirty-two studies included in the meta-analysis, only eight dealt with lymphoma. The court could not discern if Dr. Lockey and Dr. LeMasters’ opinions as to claimant were based upon the meta-analysis of the thirty-two studies, including all types of cancers, or only on the eight dealing specifically with lymphoma. The court noted, moreover, that Dr. Lockey and Dr. LeMasters asserted in their study only that there was a general association between firefighting and lymphoma, but not that claimant’s work as a firefighter actually caused him to develop NHL. Thus, the court found that the meta-analysis failed the third prong of Rule 702, which requires that the experts apply the scientific method reliably to the facts of the case. Indeed, the court found, claimant’s brief stated as much, at least with respect to Dr. LeMasters, indicating that she “felt it was beyond her expertise to apply epidemiological evidence to an individual’s medical condition to arrive at an informed expert opinion on ‘specific causation.’ ”
¶ 24. Finally, the court reasoned that even if the meta-analysis conducted by Dr. Lockey and Dr. LeMasters was a reliable scientific method, which it may have been, the court had no way to know if it was based upon sufficient facts or data as required by Rule 702(1). As stated above, these experts were not persuasive in presenting their findings, and the court could not determine which studies of which cancers were included in the meta-analysis.
¶ 25. Claimant challenges these findings and conclusions on appeal. We begin with the court’s evaluation of Dr. Guidotti’s testimony. Claimant raises two related arguments. First, he asserts that the court should not have used a relative risk of 2.0 as a benchmark in evaluating whether the experts’ testimony was based on sufficient facts or data. He also maintains that the court erred in stating that six of the epidemiological studies he offered showed “little or no association” between NHL and firefighting. In a related vein, claimant argues that, contrary to the trial court’s *245finding, Dr. Guidotti adequately explained his methodology, and his reliance on a “weight of the evidence” methodology was scientifically acceptable. Claimant argues that the court should have credited Dr. Guidotti’s explanation of why the “true risk” ratio for the type of cancer suffered by claimant “probably exceeds 2.0,” notwithstanding the results in the majority of the epidemiological studies upon which he relied.9
 ¶ 26. We find these arguments without merit. Claimant was required to show by a preponderance of the evidence that his NHL was causally related to his employment. To meet his burden of proof, claimant relied on epidemiological studies, studies that focus on general causation rather than specific causation. Dr. Guidotti acknowledged that the demonstration of “more likely than not” in the epidemiological literature corresponded to a relative risk, or an odds ratio, of 2.0, although he argued that this standard should not be followed here.10 Given claimant’s burden of proof, however, and the inherent limitations of epidemiological data in addressing specific causation, the trial court reasonably found the 2.0 standard to be a helpful benchmark in evaluating the epidemiological evidence underlying Dr. Guidotti’s opinion. See Magistrini, 180 F. Supp. 2d at 595 (in determining admissibility of expert testimony, the trial court must “examine the expert’s conclusions in order to determine whether they could reliably flow from the facts known to the expert and the methodology used.” (quotation omitted)).
*246¶ 27. Other courts have similarly looked to the 2.0 standard in evaluating epidemiological evidence. See Havner, 953 S.W.2d at 716 (concluding that properly designed and executed epidemiological studies may be part of the evidence supporting causation in a toxic tort case, and finding a rational basis for relating the requirement that there be more than a “doubling of the risk” to the “more likely than not” burden of proof) (citing cases where other courts have found that “the requirement of a more than 50% probability means that epidemiological evidence must show that the risk of an injury or condition in the exposed population was more than double the risk in the unexposed or control population”); see also Daubert v. Merrell Dow Pharms., Inc. (Daubert II), 43 F.3d 1311, 1321 (9th Cir. 1995) (“For an epidemiological study to show causation under a preponderance standard, the relative risk . . . arising from the epidemiological data will, at a minimum, have to exceed 2.” (quotation omitted)); Sanderson v. Int’l Flavors & Fragrances, Inc., 950 F. Supp. 981, 998 n.17 (C.D. Cal. 1996) (plaintiff must show more than that certain chemical increased somewhat the likelihood of particular injury; he or she must show that it more than doubled the risk — this would then offer support for an opinion that it was more likely than not the source of plaintiff’s injury); Magistrini, 180 F. Supp. 2d at 605 n.27 (“[M]any courts confronted with determining the reliability of expert testimony look at whether or not the studies relied upon by the expert are statistically significant.”) (citing Joiner, 522 U.S. at 145-46 (evaluating reliability of epidemiological data based on statistical significance); In re TMI Litig., 193 F.3d 613, 711-12 (3d Cir. 1999) (finding epidemiology study unreliable because results not statistically significant)). Indeed, the Daubert II court found that a relative risk of less than two “actually tends to disprove legal causation,” as it shows that the agent in question does not double the likelihood of developing a particular injury. 43 F.3d at 1321. Thus, as the court explained, epidemiological studies showing a relative risk less than two “would not be helpful, and indeed would only serve to confuse the jury, if offered to prove rather than refute causation.” Id.
 ¶ 28. We also recognize that the very use of epidemiological evidence to show specific causation reflects a compromise, given that epidemiological studies “cannot indicate the actual cause of a given individual’s disease or condition.” Havner, 953 S.W.2d at 718. As the Havner court persuasively reasoned,
*247the law must balance the need to compensate those who have been injured by the wrongful actions of another with the concept deeply imbedded in our jurisprudence that a defendant cannot be found liable for an injury unless the preponderance of the evidence supports cause in fact. The use of scientifically reliable epidemiological studies and the requirement of more than a doubling of the risk strikes a balance between the needs of our legal system and the limits of science.
Id, Mindful of this balance, we conclude that the trial court did not abuse its discretion in considering a relative risk greater than 2.0 as a reasonable and helpful benchmark under the circumstances presented here.
¶29. We view the court’s finding of “little or no association” between lymphomas and firefighting in six of the eight epidemiological studies in the context of its discussion of statistically significant risks. While “association” may have been the wrong word, we reject claimant’s assertion that the court’s use of this term reflects a fundamental misunderstanding of the scientific data.11 We note, moreover, that claimant’s own expert, Dr. Loekey, testified that there was no association shown between firefighting and NHL if one looked at the Baris, Demers, and Aronson studies individually. Additionally, the Baris and Giles studies included the number 1.0 in the range of possible values for relative risk between NHL and firefighting, which illustrates the lack of a statistically significant association. See In re Viagra Prods. Liab. Litig., 572 F. Supp. 2d 1071, 1078-79 (D. Minn. 2008) (“It is generally accepted that if the confidence interval is so great that it includes the number 1.0, then the study will be said to *248show no statistically significant association between the factor and the disease.” (quotation omitted)).12 Claimant fails to show that the court’s statement constitutes reversible error.
¶ 30. We turn next to the specific methodology employed by Dr. Guidotti in reaching his conclusion that firefighting caused claimant’s NHL. Dr. Guidotti stated that his opinion was based on his “interpretation of the literature.” He maintained that his interpretation was supported by “available evidence in the extant literature,” and he later reiterated his conclusion that “the weight of evidence favors the interpretation that [claimant’s] lymphoma arose from work as a firefighter.” As noted above, claimant argues that Dr. Guidotti’s methodology was sound. The court concluded otherwise, finding that Dr. Guidotti’s opinion was not based on sufficient facts or data, and that Dr. Guidotti had not applied scientific principles and methods reliably to the facts of this case. The court did not abuse its discretion in reaching its conclusion. See USGen New Eng., Inc. v. Town of Rockingham, 2004 VT 90, ¶ 24, 177 Vt. 193, 862 A.2d 269 (party claiming abuse of discretion must show that court’s decision was “made for reasons clearly untenable” or that it was “unreasonable”).
¶ 31. It is true, as claimant asserts, that other courts have discussed a “weight-of-the-evidence” approach. Yet those courts have also required far more information in support of such an approach than Dr. Guidotti provided here. As is often repeated, there must be “a scientific method of weighting that is used and explained,” Magistrini, 180 F. Supp. 2d at 607, and an expert’s opinion cannot be based “on subjective belief or unsupported speculation.” Id. at 594 (quotation omitted). By detailing the *249weight given to each component, an expert demonstrates that “the “weight-of-the-evidence’ methodology is truly a methodology, rather than a mere conclusion-oriented selection process that weighs more heavily those studies that supported an outcome.” Id. at 607.
¶ 32. In Magistrini, for example, an expert witness proposed to testify, based on a weight-of-the-evidence analysis, that the plaintiffs leukemia was caused by her exposure to a particular chemical. Id. at 599-601. The court found the testimony inadmissible, finding “the single most serious flaw [in the expert testimony] is the most basic: [the expert] simply has not set forth the methodology he used to weigh the evidence.” Id. at 606. As the Magistrini court explained, “because the weight-of-the-evidence methodology involves substantial judgment on the part of the expert, it is crucial that the expert supply his method for weighting the studies he has chosen to include in order to prevent a mere listing of studies and jumping to a conclusion.” Id. at 602. In Magistrini, the expert’s “failure to adequately address the relative risks found in the studies that he relied on weighted] heavily in th[e] Court’s ultimate conclusion that his methodology [was] not sufficiently reliable to pass through the ‘gate’ to the jury.” Id. at 606.
¶ 33. The trial court was faced with a similar situation here. Dr. Guidotti did not specify the precise weight he gave to each study or how he reached his conclusion that the studies, taken together, demonstrated a statistically significant result, when seventy-five percent of the studies, individually, failed to reach that conclusion. Dr. Guidotti stated that his analysis was “based on the observation that improving the accuracy of cumulative exposure to combustion products in whatever data set is available results in an increased estimate of risk, which reflects the strength of association.” He opined that “[i]n the key studies available, a career of 40 years clearly places a firefighter at increased risk of NHL and is sufficient to conclude that the risk was in fact elevated to at least an approximate doubling.” How? Why? Dr. Guidotti failed to specifically account for the level of relative risk shown by each of the studies, describe what precise weight was given to each study, particularly in light of the different types of studies involved, or account specifically for showings such as that found in the Baris study that the level of excess risk of NHL was not associated with an increased number of lifetime runs, and that, in fact, the standardized mortality ratio was highest in those individuals who made the lowest number of firefighting runs.
*250 ¶ 34. As the United States Supreme Court has recognized, the very purpose of Daubert “is to make certain that an expert, whether basing testimony upon professional studies or personal experience, employs in the courtroom the same level of intellectual rigor that characterizes the practice of an expert in the relevant field.” Kumho Tire Co. v. Carmichael, 526 U.S. 137, 152 (1999). Where six of eight epidemiological studies did not show a statistically significant risk, it was reasonable for the trial court to conclude that Dr. Guidotti’s expert opinion that claimant’s NHL was more likely than not caused by firefighting lacked a solid and reliable foundation. See id. at 152 (“[T]he trial judge must have considerable leeway in deciding in a particular case how to go about determining whether particular expert testimony is reliable.”).
¶ 35. Claimant suggests for the first time on appeal that specific causation is established by the Figgs and Sama studies alone. Claimant’s experts made no such assertion below, however, and we will not address this argument for the first time on appeal. See Lane v. Town of Grafton, 166 Vt. 148, 153, 689 A.2d 455, 457 (1997) (“Failure to raise a reason why summary judgment should not be granted at the trial level precludes raising it on appeal.”). Indeed, we note that this position is at odds with the weight-of-the-evidence approach taken by both Dr. Guidotti and Dr. Lockey. In fact, Dr. Lockey specifically testified that he would not rely on just one study to reach a conclusion, as that would be inadequate grounds on which to base an opinion.
 ¶ 36. Of course, we are not blind to fundamental misapplications of Daubert, but claimant fails to show that is what occurred here. See USGen, 2004 VT 90, ¶ 24 (Supreme Court will affirm the trial court’s decision “[ajbsent a clear showing of judicial error,” but Court will also “engage in a substantial and thorough analysis of the trial court’s decision and order to ensure that the trial judge’s decision was in accordance with Daubert and our applicable precedents” (quotation omitted)). The requirement that an expert testify to “scientific knowledge means that the expert’s opinion must be based on the ‘methods and procedures of science’ rather than on ‘subjective belief or unsupported speculation’; the expert must have ‘good grounds’ for his or her belief.” Magistrini, 180 F. Supp. 2d at 594. “[W]hen an expert opinion is based on data, a methodology, or studies that are simply inad*251equate to support the conclusions reached, Daubert and Rule 702 mandate the exclusion of that unreliable opinion testimony.” Amorgianos v. Nat’l R.R. Passenger Corp., 303 F.3d 256, 266 (2d Cir. 2002). The trial court identified reasonable grounds for its decision, and as we have often repeated, it is for the trial court, not this Court, to weigh the evidence and assess the credibility of witnesses. See, e.g., Chase v. Bowen, 2008 VT 12, ¶ 15, 183 Vt. 187, 945 A.2d 901 (it is exclusively the province of the trial court to assess the credibility of the witnesses and weigh the persuasiveness of the evidence). We find no abuse of discretion in its exclusion of Dr. Guidotti’s testimony here.
¶ 37. We next consider the court’s evaluation of the meta-analysis conducted by Dr. Lockey and Dr. LeMasters. Claimant maintains that the court miseharacterized the methodology and scientific reliability of this study. Claimant also asserts that, contrary to the court’s statement that it could not discern what studies were included, it was clear from the “summary risk estimate” that eight studies were used in the analysis of the association between NHL and firefighting.
¶ 38. While it is not entirely clear from the introduction to the meta-analysis, it does appear, as claimant argues, that the meta-analysis with respect to NHL was based on eight studies, apparently the same eight studies used by Dr. Guidotti in reaching his conclusion. The meta-analysis found the summary risk estimate for NHL to be 1.51, again a value less than 2.0. The study concluded that the findings of an association between firefighting and significant increased risk for specific types of cancer raised red flags and should encourage further development of innovative comfortable protective equipment, allowing firefighters to do their jobs without compromising their health. A conclusion that NHL is considered a “probable cancer risk” for firefighters is not sufficient to establish that claimant’s NHL was caused by firefighting, particularly given that this conclusion rests on a finding of relative risk of less than 2.0. See Sanderson, 950 F. Supp. at 1000 (where expert’s probability estimate was “not founded upon epidemiological studies showing a relative risk of greater than two, or some other evidence that would lend a scientific foundation to the assertion that [a particular agent] more likely than not caused plaintiffs injuries, it does not constitute a valid scientific connection to the pertinent inquiry of causation” (quotation omitted)). As the trial court found, moreover, the study *252did not in fact assert that firefighting caused claimant’s NHL, and Dr. Lockey failed to adequately explain how this study showed that it was more likely than not that firefighting caused claimant’s cancer. See Daubert II, 43 F.3d at 1322 (in order for expert testimony of causation to have a valid scientific connection to the pertinent inquiry, it must demonstrate that exposure to agent actually caused plaintiffs injuries or, at least, that such exposure more than doubled plaintiffs risk of suffering those injuries; otherwise expert testimony does not assist the trier of fact in resolving the issue of causation).
¶ 39. We reject claimant’s assertion that the trial court misapprehended the foundation of Dr. Lockey’s testimony. According to claimant, Dr. Lockey did not rely solely on meta-analysis in reaching his conclusion that claimant’s NHL was caused by firefighting. Rather, claimant argues, Dr. Lockey stated that he examined the potential exposures experienced by firefighters; he considered whether there were any nonoccupational factors as applied to claimant that were known to be associated with a risk for NHL; and he examined all of the published and peer-reviewed medical literature as it applied to firefighters and the occurrence of NHL. According to claimant, Dr. Lockey found that the majority of studies demonstrated a significantly elevated risk from a statistical perspective, but not at a statistically significant level. Claimant asserts that, in Dr. Lockey’s expert opinion, the scientific data demonstrated a consistent cause-effect relationship between firefighting and NHL.
¶ 40. Dr. Lockey may have testified as to other things, but his conclusion as to causation plainly rested, as it must, on his evaluation of the scientific evidence, which here, was his interpretation of epidemiological studies. Our law requires claimant to show, not merely that firefighting increased the likelihood of injury, but that it more likely than not caused his disease. See id. (expressing similar sentiment). Claimant failed to establish good grounds for such a conclusion here. We need not consider Dr. LeMasters’ testimony separately because she had no opinion whether claimant’s NHL was caused by firefighting, and thus, her opinion alone would be insufficient to meet claimant’s burden of proof. The fact that she was not a physician, and thus, incapable of opining as to causation, is irrelevant.
 ¶ 41. As set forth above, the trial court was obligated to evaluate the reliability and relevance of the proposed expert *253testimony. The Legislature has recognized the difficulty in establishing causation in cases similar to this one, and it has changed the way in which such cases will be evaluated in the future. See 2007, No. 42, § 1 (recognizing that establishing causation requires significant expert testimony and that it is difficult and expensive to gather and establish evidence of work-related causation for certain types of cancers suffered disproportionately by firefighters). In this case, however, there was no presumption of causation available to claimant, and we conclude that the court acted within its discretion in excluding the expert testimony at issue here. As one court has explained,
[o]ur legal system requires that claimants prove their cases by a preponderance of the evidence. In keeping with this sound proposition at the heart of our jurisprudence, the law should not be hasty to impose liability when scientifically reliable evidence is unavailable. As Judge Posner has said, “[l]aw lags science; it does not lead it.”
Havner, 953 S.W.2d at 728; see also Sanderson, 950 F. Supp. at 1004 (while keeping doubtful science out of law will on occasion prevent factfinder from learning of authentic insights and innovations, Rule 702 reflects the balance struck between the needs of science and the needs of law, and framers of Rule 702 “did well to make law a prisoner to science, not the other way around”). Without evidence of specific causation, summary judgment was properly granted to insurer.

Affirmed.

 The appellant in this case is the Estate of Albert George, but for simplicity’s sake, we refer to appellant here as “claimant.”

 The Department of Labor apparently admits scientific evidence “if it is ‘plausible,’ leaving the ultimate weighing of that evidence to the finder of fact — first a hearing officer, then the Commissioner.”

 Claimant appears to have recognized this basic principle below. In response to insurer’s statement of undisputed material facts, claimant asserted that “[f]or purposes of this de novo trial, the findings and conclusions of the Department of Labor are wholly irrelevant.” Indeed, he asked that any reference to the Department’s conclusions “be stricken from the record.”

 We note that Vermont law now specifically provides that a firefighter who suffers disability or death from certain types of cancer is “presumed to have suffered the cancer as a result of exposure to conditions in the line of duty, unless it is shown by a preponderance of the evidence that the cancer was caused by non-service-connected risk factors or non-service-connected exposure,” with certain limitations set forth by statute. 21 V.S.A. § 601(11)(E).

 These studies and others are cited and collected within G. LeMasters et al., Cancer Risk Among Firefighters: A Review and Meta-analysis of 32 Studies, 48 J. Em. Med. 1189 (2006), available at http://www.iaff.org/HS/PDF/ Cancer%20Risk%20Among%20Firefighters%20-%20UC%20Study.pdf.

 Green cautions, however, that “before an association or relative risk is used to make a statement about the probability of individual causation, the inferential judgment. . . that the association is truly causal rather than spurious is required: An agent cannot be considered to cause the illness of a specific person unless it is recognized as a cause of that disease in general.” Id. at 383-84 (quotation omitted).

 The Magistrini court explained this process in greater detail as follows:
Epidemiological studies attempt to identify agents that are associated with an increased risk of disease. Thus, the first question an epidemiologist asks is whether an association exists between exposure to an agent and a particular disease. An association between exposure to an agent and a disease exists when the two occur together more frequently than they would by mere chance. Once an association is observed, the scientist undertaking the study must assess the strength of the association as well as whether the reason for the observed association is due to bias, chance or real effect.
Relative risk is commonly calculated by dividing the risk of developing a disease observed in an exposed group by the risk observed in an unexposed, but otherwise similar group. If the risks of the unexposed and exposed are the same, then the relative risk estimate (which mathematically is simply the former divided by the latter) is 1.0. This value is also called the null value, and indicates that exposure is not associated with the disease in that study. Thus, a relative risk of 1.0 means that the agent has no effect on the incidence of disease. Similarly, if the relative risk estimate is 1.3, then risk appears to be 30% higher among the exposed compared to the non-exposed. When the relative risk reaches 2.0, the risk has doubled, indicating that the risk is twice as high among the exposed group as compared to the non-exposed group. Thus, the threshold for concluding that an agent was more likely than not the cause of an individual’s disease is a relative risk greater than 2.0.
180 F. Supp. 2d at 591 (quotation omitted).

 As Dr. Guidotti noted, NHL “is a collection of widely disparate diseases that are not commonly separated in epidemiological studies.” He stated that NHLs consist of at least thirty recognized types, and he opined that new types will be identified as immunological and genomic methods become more sophisticated.

 The dissent concludes sua sponte that the court abused its discretion by failing to hold a Daubert hearing. No party raises this issue on appeal. In fact, the court did hold a hearing on the motion for summary judgment, and heard argument from both parties as to the admissibility of this evidence under Daubert and Rule 702. The parties also provided extensive written argument and evidence concerning the admissibility of claimant’s expert testimony in their motions for summary judgment. The trial court had discretion in deciding whether an evidentiary hearing was necessary, and it acted within its discretion here. See, e.g., Nelson v. Tenn. Gas Pipeline Co., 243 F.3d 244, 249 (6th Cir. 2001) (reaching similar conclusion, and rejecting argument that trial court must hold evidentiary hearing to comply with Daubert, explaining that United States Supreme Court has made clear that decision whether to hold hearing falls within trial court’s discretion).

 This appears to be a slight misstatement, as it appears that a relative risk of greater than 2.0 corresponds to a legal standard of “more likely than not.” See, e.g., Magistrini, 180 F. Supp. 2d at 591.

 As one court explains:
Association is a term of art in epidemiology. It is defined as “[t]he degree of statistical dependence between two or more events or variables. Events are said to be associated when they occur more or less frequently together than one would expect by chance. Association does not necessarily imply a causal relationship. Events are said not to have an association when the agent (or independent variable) has no apparent effect on the incidence of a disease (the dependent variable).”
In re TMI Litig., 193 F.3d at 710 n.159 (quoting L. Bailey et al., Reference Guide on Epidemiology, in Reference Manual on Scientific Evidence 121, 171 (Federal Judicial Center ed., 1st ed. 1994)).

 A “confidence interval” is:
“[a] range of values within which the results of a study sample would be likely to fall if the study were repeated numerous times. . . . The width of the confidence interval provides an indication of the precision of the point estimate or relative risk found in the study; the narrower the confidence interval, the greater the confidence in the relative risk estimate found in the study. Where the confidence interval contains a relative risk of 1.0, the results of the study are not statistically significant.”
In re TMI Litig., 193 F.3d at 711 n.165 (quoting Bailey, supra, at 173). We note that the Burnett study, cited by claimant in his brief as showing a relative risk of 1.32, does not appear to have been included in the printed case.