Defendants appeal from an order granting plaintiff s motion for a new trial after the jury returned a defense verdict in this personal injury case. ORCP 64 B. Plaintiff cross-appeals, assigning error to several of the trial court’s eviden-tiary rulings. We reverse on appeal; on cross-appeal, we affirm without discussion.
While plaintiff was snowboarding at a ski area that defendants operate on Mt. Hood, he snowboarded into a wooded area between two ski runs, Whoopee and Reservoir Hill. In doing so, he fell into Reservoir Creek, which runs through the wooded area, and as a result, he was seriously injured. On the Reservoir Hill side, the wooded area was entirely roped off at the time of the accident as a warning to skiers, but on the Whoopee side, there were places where there were no ropes or other warnings. Plaintiff testified that he entered the wooded area at a nonroped portion of the Whoopee side. In his complaint, he alleged that defendants were negligent in, among other things, “failing to install and maintain barriers and/or warnings sufficient to prevent skiers or snow boarders from accidentally skiing or snow boarding into the creek bed from the west or south side.” A major issue at trial was whether plaintiff actually entered the area from the Whoopee side, or, as defendants argued, based on the evidence of snowboard tracks, from the Reservoir Hill side. No witness saw plaintiff enter the area.
During the trial, defendants introduced evidence that plaintiff had smoked marijuana while he was on the way to the ski area the morning of the accident. The evidence included the results of a quantitative test of plaintiffs urine after the accident that showed 603 nanograms of cannabi-noids per milliliter. According to defendants’ expert, Dr. Griffin, that level of cannabinoids indicated that plaintiff was impaired as a result of the marijuana at the time of the accident. Plaintiff first learned of the existence of the quantitative test immediately before trial, during the argument on his motion in limine to exclude all evidence of his marijuana use. He had requested all of his medical records from the appropriate providers during discovery and had received a copy of *434the original screening test of his urine, which merely showed the presence of marijuana metabolites. After receiving that test, he specifically asked the hospital whether it had any record of a quantitative test. The person in charge of the hospital’s records responded that there was no such record and that it was not the hospital’s policy to perform additional tests. However, despite those denials, a laboratory connected with the hospital had in fact performed the quantitative test that defendants introduced. Defendants apparently learned of that test as a result of consulting with an expert who worked at the laboratory that performed it. After learning of the test, defendants subpoenaed the test result from that laboratory without providing notice to plaintiff, either before or after issuing the subpoena, and without having a medical release from him.
Because plaintiff had not received a copy of the test report, he first learned of its existence as well as Griffin’s opinion regarding impairment during the argument on the motion in limine. As a result, plaintiff withdrew his motion in limine, and the evidence was admitted at trial over his objections that defendants had not shown that it was valid scientific evidence. Defendants used the evidence at trial both to discredit plaintiff’s version of how the accident occurred, by suggesting that the effects of the marijuana impaired his ability to remember what happened, and to support their argument that the accident was the result of plaintiffs, rather than defendants’, negligence. After the parties rested, the jury returned its verdict, answering “No” to the following question: “Were defendants at fault in one or more of the ways alleged by the plaintiff, and, if so, was such fault a cause of damages to plaintiff?”1
After trial, plaintiff moved for a new trial under ORCP 64 B(l) - (4). ORCP 64 provides that a trial court may set aside a verdict and grant a new trial on grounds that include:
“B(l) Irregularity in the proceedings of the court, jury or adverse party, or any order of the court, or abuse of *435discretion, by which such party was prevented from having fair trial.
“B(2) Misconduct of the jury or prevailing party.
“B(3) Accident or surprise which ordinary prudence could not have guarded against.
“B(4) Newly discovered evidence, material for the party making the application, which such party could not with reasonable diligence have discovered and produced at the trial.”
The trial court granted plaintiffs motion for a new trial. In explaining its reasoning as to why it was granting the motion, the court prefaced its ruling by remarking:
“I’m going to talk a little about this because I want the Court of Appeals to understand why I’m granting this motion for new trial. I have not granted a motion for a new trial since I have been on the bench.”
The court then stated its reasoning:
“I’m going to start with the evidence. At this point now that the science is in, if the matter was before me prior to trial, unless it was further developed in a different manner than what’s been submitted in the affidavits and briefs, I would not allow Griffin to testify about the effect of marijuana, because I think it is contrary to established science.
“Okay. How do we—how did we get to this point that I did not reach that conclusion until well after the trial? I think there was a problem in the response by Legacy. I think there was a problem in the analysis, the hip shot analysis by Brady [plaintiffs expert witness]. But do we end this trial and then have another lawsuit against the hospital for releasing their records without authority to the defense and, as a second prong, failing to adequately respond to the plaintiffs requests for his own records, and try that out were they—was the hospital at fault in some way for doing that? Did that cause the plaintiff to fail to recover here and therefore the hospital had to recover? I can see the case going down that track. Do we have another lawsuit against Brady for falling below the standard of care of an expert witness in not immediately sizing this up and giving the Court the information that he’s later given? I don’t think that’s good. I think this—that’s one way we could go.
*436“Was the subpoena response under [ORCP 55 [2] proper—not response, rather the procedure. I don’t believe so. I think that [ORCP 55 I] controls and that there should have been the notice and then we wouldn’t have gotten into this soup because the plaintiff would have known about this record prior to trial and evidence would have been developed. And on that point, this case just could not have been better prepared by—I think by either side.”
After digressing, the court summarized:
“So I think that the evidence on the use of marijuana would not have come into the case at all, that the reason that the plaintiff wasn’t able to present the science that reaches—leads me to that conclusion is because of conduct at the hospital, conduct of Brady and initially the irregularity in failing to follow the subpoena process.”
The above-quoted material demonstrates that the trial court based its grant of a new trial on three grounds. First, the court ruled as a matter of law that defendants’ evidence regarding plaintiffs use of marijuana before the accident occurred and Griffin’s opinion that plaintiff was impaired by that use at the time of the accident were inadmissible because Griffin’s opinion did not constitute valid scientific evidence. As will be explained later in this opinion in more detail, that conclusion constitutes legal error. Second, the trial court believed incorrectly that the purported procedural irregularities regarding Legacy’s response to plaintiffs subpoena constituted a justification under ORCP 55 I to grant a new trial. Third, and finally, the trial court ruled that a new trial would avoid a malpractice claim against Brady, plaintiffs expert witness, because of, according to the trial court, Brady’s “hip shot analysis” at trial.
On appeal, defendants make six assignments of error: (1) They assert that the trial court erred in granting plaintiffs motion for a new trial because the jury did not reach the question of comparative negligence, the question *437on which they claim that plaintiffs newly discovered evidence would have been probative. (2) They argue that plaintiff waived any error that was the basis of his motion for a new trial by withdrawing his motion in limine. (3) They claim that the trial court’s ruling that defendants violated ORCP 55 I was error. (4) They assert that the evidence offered by plaintiff is not “newly discovered evidence” within the meaning of ORCP 64 B(4). (5) They contend that
“a trial court may only supercede a jury verdict and order a new trial if there is no evidence to support the verdict. * * * [T]he heart of plaintiffs argument was that his expert disagreed with defendants’ expert regarding correlation between total cannabinoid levels and impairment.”
(6) Finally, they contend that the trial court erred when it granted partial summary judgment to plaintiff on defendants’ affirmative defense that plaintiff had released them from liability because he purchased a ticket containing a release provision and then used the ticket to ski on defendants’ ski lifts. Because defendants’ third and fourth assignments of error are dispositive, we do not consider their other assignments of error.
We return to the reasons for which the trial court granted a new trial. The trial court did not express which provisions of ORCP 64 B, in its view, authorized the grant of a new trial.3 We will therefore explore all the possibilities relied on by plaintiff in his motion. In their third assignment of error, defendants argue that the trial court erred in ruling that their action in issuing a subpoena for the result of the second, quantitative test without complying with the requirements of ORCP 55 I was “irregular” or constituted “misconduct,” thus implicating both ORCP 64 B(l) and (2). The relevant portions of ORCP 55 I provide:
“(2) If a patient or health care recipient is represented by an attorney, a true copy of a subpoena duces tecum for *438medical records of a patient or health care recipient must be served on the attorney for the patient or health care recipient not less than 14 days before the subpoena is served on a custodian or other keeper of medical records. Upon a showing of good cause, the court may shorten or lengthen the 14-day period.
* * * *
“(4) The requirements of this section apply only to subpoenas duces tecum for patient care and health care records kept by a licensed, registered or certified health practitioner as described in ORS 18.550, a health care service contractor as defined in ORS 750.005, a home health agency licensed under ORS chapter 443 or a hospice program licensed, certified or accredited under ORS chapter 443.”
ORCP 55 H(2) establishes similar requirements that apply to a subpoena duces tecum for hospital records when no hearing is scheduled and the subpoena directs delivery of the records to the attorney or party issuing the subpoena. However, ORCP 55 H(2) does not require advance notice to the plaintiff if the subpoena requires delivery of the record to a court or other authority that is conducting a deposition or a judicial or other formal hearing. It appears from the record that the laboratory informally told defendants of the result of the quantitative test before trial but did not provide them a copy. The only subpoena that defendants issued to the laboratory required its representative to bring the test result to the trial, although the record on appeal does not indicate whether the representative was to deliver it to the court or to defendants. Possibly for those reasons, plaintiff did not rely on ORCP 55 H(2) at the trial court, and he does not refer to it in this court.
It is undisputed that defendants did not comply with ORCP 55 I when they issued the subpoena for the second test. If they had done so, plaintiff would have known of the test, despite the hospital’s previous denial of its existence. Defendants argue however, that the laboratory that conducted the test was not part of the hospital where plaintiff was treated but was a separate laboratory that specialized in drug testing. To the contrary, there is evidence that the laboratory was part of the same hospital complex and that the *439laboratory’s records were part of the records of that complex. Nevertheless, ORCP 55 I, the rule on which plaintiff relies, does not apply to the laboratory. That rule, by its express language, applies to health care practitioners, not to institutions that keep records separately from practitioners. Although health care practitioners treated plaintiff at the hospital, the hospital, not the practitioners, kept the records of the laboratory tests. Because ORCP 55 I did not apply to the subpoena in question, there was no basis for the trial court to conclude that defendants’ failure to give 14 days notice of the subpoena constituted either an irregularity in the proceedings or misconduct of the prevailing party.4 The trial court erred when it relied on ORCP 55 I as a basis for granting of a new trial.
Plaintiff also relies on federal regulations concerning the confidentiality of information used for the purposes of diagnosis and treatment of drug abuse. 42 USC § 290dd-2; 42 CFR §§ 2.11 - 2.13. However, those provisions apply only to health professionals whose primary function is to provide alcohol or drug abuse diagnosis, treatment, or referral. 42 CFR § 2.12(e)(1). In this case, plaintiff did not receive drug abuse treatment or referral. Despite the positive result on the initial screening test, plaintiff stated that he did not believe that he had a chemical dependency problem and refused any treatment. Because there is no indication in the record that the quantitative test constituted a diagnosis under the federal rules, the test result was not protected. We conclude that the federal requirements are not a basis for finding that defendants acted irregularly or engaged in misconduct.
With regard to the trial court’s grant of a new trial to avoid a malpractice claim against Brady, plaintiffs expert witness, the court held in State v. Arnold, 320 Or 111, 120-21, 879 P2d 1272 (1994), that ORCP 64 B(4) is a statute like any other statute. Accordingly, this court’s task is to discern the intent of the legislature regarding the grounds upon which a new trial may be granted. Significant to this case, none of the *440enumerated grounds in ORCP 64 B authorize a court to grant a motion for a new trial to avoid a malpractice claim against an expert witness; after all, defendants are not required to endure a new trial after the jury has returned a verdict in their favor because of the performance of their adversary’s expert witness. The trial court erred by granting a new trial on a basis that is not legally cognizable.
Before we analyze the trial court’s first reason for granting a new trial, we pause to observe that, based on the above analysis, the only ground on which the grant of a new trial in this case could be upheld is ORCP 64 B(4). ORCP 64B (1) and (2) are eliminated as possibilities because plaintiff does not claim any irregularity or misconduct on the part of defendants or the jury except for the discovery issue regarding ORCP 55 I, an issue that has already been disposed of in favor of defendants. ORCP 64 B(3) authorizes trial courts to grant a new trial because of accident or surprise that ordinary prudence could not have guarded against. The general rule is that a party may not use a surprise as a basis for seeking a new trial unless the party moved for a continuance so as to respond dining the trial, thus possibly eliminating the need for a new trial. State v. Gardner, 33 Or 149, 152-53, 54 P 809 (1898); see also Transamerica Title Ins. Co. v. Millar, Inc., 258 Or 258, 263-64, 482 P2d 163 (1971); Turman v. Central Billing Bureau, 279 Or 443, 450, 568 P2d 1382 (1977) (holding that a party that is aware of a ground for a new trial during trial may not speculate on the result by failing to bring the issue to the court’s attention, intending to use the issue to seek a new trial if the outcome is not favorable). Here, although plaintiff was aware of Griffin’s testimony during trial, he never moved for a continuance so that he could respond differently than in the manner that Brady, his expert witness, testified. That leaves only ORCP 64 B(4) as a possible basis for granting the new trial.
In Arnold, the court specified,
“[W]e hold that evidence that may justify a court in granting a new trial [under ORCP 64B (4)] must meet the following requirements:
“(1) It must be such as will probably change the result if a new trial is granted;
*441“(2) It must be such as, with reasonable diligence, could not have been discovered before or during the trial;
“(3) It must be such that it cannot, with reasonable diligence, be used during trial;
“(4) It must be material to an issue;
“(5) It must not be merely cumulative;
“(6) It must not be merely impeaching or contradicting of former evidence.”
320 Or at 120-21 (footnote omitted).
At trial, the jury heard conflicting expert opinions from Griffin and from Brady, plaintiffs expert, about whether impairment at the time of the accident could be determined from the available evidence; yet the jury returned a verdict for defendants. If the evidence of plaintiffs marijuana use in Griffin’s opinion regarding plaintiffs impairment was properly admitted at trial (contrary to the trial court’s post-trial ruling), then the question arises whether plaintiff is otherwise entitled to a new trial under ORCP 64 B(4). Consequently, the analysis regarding the trial court’s riding about the admissibility of plaintiffs use of marijuana and Griffin’s opinion as to plaintiffs impairment breaks into two sub-parts: (1) whether the trial court erred in admitting the evidence of plaintiffs marijuana use and Griffin’s opinion at trial of the effect on plaintiff from that use; and (2) assuming that that evidence was admissible, whether plaintiff has otherwise demonstrated an entitlement to the grant of a new trial under ORCP 64 B(4).
To resolve whether Griffin’s opinion testimony about plaintiffs impairment at the time of the accident due to marijuana ingestion was properly admitted requires an application of the Supreme Court’s case law regarding the admission of scientific evidence. In State v. O’Key, 321 Or 285, 899 P2d 663 (1995), the court held that the admissibility of scientific evidence is governed by OEC 401, 702, and 403.5 Under OEC 401, evidence is relevant if it has the tendency to make the existence of any fact that is of consequence to the determination of the action more probable or less probable than it *442would be without the evidence. Here, defendants offered the evidence of plaintiffs impairment due to marijuana for two relevant reasons, to impeach his recollection of how the accident occurred and to prove that he was at fault in causing his injuries.
The next inquiry is under OEC 702, which defines the permissible sphere of expert testimony as whether “scientific, technical or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue [.]” The O’Key court applied a multifactor test that includes whether the theory or technique could be tested; whether the theory or technique had been subjected to peer review and publication; whether there is a known or potential rate of error in the scientific process; whether there exist operational standards that regulate the technique or theory; whether the theory or technique is accepted in the relevant scientific community; whether the expert’s qualifications qualify him as an expert in the field; whether the use of the theory or technique is widely used, the extent to which other courts admit its use, its novelty, the extent to which the theory or technique relies on a subjective interpretation; and the presence or lack of existence of safeguards. None of the above factors is decisive, nor is the list exclusive. In addition, the evidence must meet the helpfulness requirement of OEC 702.
According to the record, defendants’ expert, Griffin, is a medical doctor, board-certified in occupational medicine, and a review officer for OSHA compliance. He specializes in reviewing drug test results and has been specially trained in the effects of marijuana on the human body, including the decline of the effects of marijuana over time. He also supervises laboratory testing procedures for compliance with regulations and testing procedures. As we noted previously, Griffin testified that he reviews about 11,000 drug test results annually and regularly deals with the kinds of test results that occurred in this case. Out of the results that he had reviewed in the ten months preceding trial, about 990 were positive marijuana tests, but fewer than 20 of those involved test results above 500 nanograms/ml. Plaintiffs test level was 603 nanograms/ml at 8:45 p.m. on the day of the accident, which was, in Griffin’s opinion, “an exceptionally *443high level” in comparison with the test results that he typically evaluated. Plaintiff had consumed marijuana of an unknown quantity sometime the morning of the accident, and the accident occurred sometime around noon on that day. According to Griffin, the correlation between impairment and cannabinoid levels in urine samples has been the subject of published studies and those studies have been subject to peer review. Griffin submitted copies of those studies to the trial court before it ruled on plaintiffs motion for a new trial.
Plaintiff in his motion for a new trial, however, characterized Griffin’s testimony at trial as a bald assertion that a measure of total cannabinoids that he considered high must mean that plaintiff was impaired at the time of his injuries. According to plaintiff, the scientific literature is “unanimous” that such a correlation cannot be scientifically made. In his reply brief to the trial corut on the motion for new trial, plaintiff criticized the conclusions that Griffin drew from each of the studies on which Griffin relied and, on appeal, plaintiff incorporates by reference those criticisms.6
Ultimately, the question is whether plaintiffs criticisms of Griffin’s opinion go to the admissibility of his testimony or to the weight that the trier of fact gives it. In that regard, the case of Jennings v. Baxter Healthcare Corp., 331 Or 285,14 P3d 596 (2000), informs the issue. At issue in that case was the admissibility of the testimony of a board-certified neurologist with an advanced degree in neurophysiology. He testified, based on his clinical experience with patients, that the silicone from the plaintiffs breast implants had migrated throughout her body and caused her personal injuries. On appeal, the Supreme Court upheld the admissibility of his opinion as scientific evidence. The court focused on the physician’s methodology that led to his opinion rather than on his ultimate conclusion. The court noted that, although the witness’s hypothesis had not been tested by others, nor had it been subject to peer review or been published, *444OEC 702 does not preclude the admission of novel scientific evidence. Id. at 307. Ultimately, the court concluded that, because the witness’s methodology supported his conclusions, his testimony was admissible as scientific evidence.
The governing principle from Jennings is that scientific evidence will be admissible if the evidence is based on a methodology that has scientific validity, even if other scientists or experts might be unwilling to draw the same conclusion. In this case, Griffin relied on the test of plaintiffs urine after the accident, his clinical experience with such test results, and the findings of certain studies as the basis for his opinion that plaintiff was impaired at the time of the accident. He compared the effect of alcohol on the human body to the effect of marijuana on the human body and testified that there is a known range of marijuana in the body above which “nearly all or substantially all adults would be impaired.” He testified that, in his experience and based on reviews of medical literature, “the range at which one can with confidence state that all or substantially all adults would be impaired is above 400 [nanograms per milliliter total cannabinoids].” He explained, “So if we’re looking at a urine level of 603 nano-grams at 8:45 in the evening, and we can see that this is a level in the urine, we can anticipate accurately that sometime five, six, seven hours back was the peak level in the blood and the peak effect on the individual’s psycho-motor function [.]”
For purposes of discussion, we assume that members of the scientific community would disagree with Griffin that a qualified medical person could opine with reasonable medical probability that plaintiff was impaired at the time of the accident based on plaintiffs test result. For example, in his affidavit in support of plaintiffs motion for a new trial, plaintiffs expert explained that the active ingredient of marijuana associated with impairment of the human body is called “Delta 9-THC.” When ingested, that ingredient is metabolized by the body within four hours or less into several metabolites. Once metabolized, the primary metabolite left in the body is known as carboxy-THC and is not known to cause impairment. “[U]rine tests for carboxy-THC may reflect the presence of metabolites from both recent use (use that day) and several days prior, without distinguishing *445which metabolites are from which use.”7 Thus, plaintiffs expert concluded in his affidavit that the carboxy-THC test result relied on by defendants’ expert is not a reliable indicator of the active ingredient of marijuana in plaintiffs body at the time of the accident because the test does not discern when the marijuana was ingested, nor does it indicate the amount of the active ingredient of marijuana in the body as distinguished from other metabolites or cannabinoids of marijuana that do not cause impairment.8
In response to the post-trial challenge made by Brady to Griffin’s trial testimony, Griffin filed a controverting affidavit in which he attached copies of scientific literature, including a study that suggested, based on tests of airplane pilots, that the “carry-over effects of low to moderate social doses [of marijuana] may produce significant impairment for as long as 24 h [sic] on complex human performance involving machines.” Griffin also averred in his post-trial affidavit that “a mine level of 603 nanograms per mil total cannabinoids means” that the active cannabinoid level in that same sample ranges from a “6-to-l to a 10-to-l ratio.” Griffin reiterated, “Based upon my experience, a urine level of603 nanograms per mil is very high.” Finally, he said in his affidavit:
“Based upon the studies cited above, the studies cited in my testimony, plaintiffs admission that he smoked marijuana that morning, my training and experience, it is my opinion that plaintiff was impaired at the time of his accident. My opinion is based upon a reasonable medical probability.”
We conclude on this record that Griffin’s opinion satisfies the admissibility requirements for scientific evidence because of the methodology used by him to arrive at his conclusion. His opinion is based on scientific facts derived from scientific studies and his own clinical experience as well as on empirical reasoning. As we understand his point, from the *446fact that, at 8:45 p.m. on the day of the accident, plaintiff’s urine contained 603 nanograms/ml, it can be inferred that his urine also contained active cannabinoids at that time based on a known ratio. In addition, Griffin’s opinion takes into account the fact that the effect of marijuana peaks one hour after consumption and then subsequently dissipates. Accordingly, Griffin concluded, “So a level of 600 implies to me that any adult at that level would have been impaired.” Thus, in light of the dissipation rate over an eight-hour period, Griffin drew the inference from plaintiff’s test result based on his experience and scientific literature that the active ingredients of marijuana in plaintiff’s body must have been high enough at the time of the accident to have caused him to be impaired.
Griffin’s methodology may be novel, as plaintiff asserts, and there may be other factors, including the fact that the test performed on plaintiff’s urine measured the residual amount of total cannabinoids ingested over a 72-hour period of time, that challenge the accuracy of Griffin’s opinion. In addition, as plaintiff’s expert’s affidavit demonstrates, there exist scientific opinions contrary to Griffin’s opinion. But differing opinions based on scientific methodology do not necessarily result, under the applicable law, in the exclusion of one of the opinions. Rather, generally, a conflict in scientific opinion presents a question of weight to be resolved by the trier of fact. Here, we hold that the arguments raised by plaintiff go to the weight to be given Griffin’s testimony and not its admissibility in light of the evidence of the high level of cannabinoids found in plaintiff’s urine some eight hours after the accident and Griffin’s experience in evaluating test levels. As the court said in O’Key, “[t]he scientific method is a validation technique consisting of the formulation of hypotheses, followed by observation or experimentation to test the hypotheses.” 321 Or at 292. In the same manner, “ ‘clinical diagnoses’ bear the mark of science.” Jennings, 331 Or at 304. Griffin’s use of empirical reasoning based on scientific facts and his reliance on his own clinical experience and the scientific literature to which he referred demonstrate a methodology that satisfied the requirements of the law for purposes of admissibility. Thus, as a matter of law, Griffin’s testimony was admissible, and the trial court *447erred when it ruled, based on the information supplied by plaintiff in support of his motion for a new trial, that the evidence of marijuana usage and Griffin’s opinion testimony about plaintiffs impairment was inadmissible. In other words, the trial court correctly admitted into evidence the test result and Griffin’s opinion during the trial, and that evidence would also be admissible in the event a new trial occurs.
We turn now to the second part of the analysis. Having concluded that evidence of plaintiffs marijuana use and Griffin’s opinion regarding the effect of its use on plaintiff are admissible, the issue is whether plaintiff otherwise is entitled to a new trial on this record. ORCP 64 B(4) requires that the evidence that entitles a movant to a new trial must be “newly discovered” evidence, evidence that will probably change the result if a new trial is granted and evidence that reasonably could not have been discovered or used at trial. Arnold, 320 Or at 120. In plaintiffs motion for a new trial, he described the “newly discovered evidence” that justified the grant of a new trial under ORCP 64 B(4):
“Plaintiff discovered the additional drug test on the first day of tr[ia]l. Over the course of trial and afterwards, Plaintiff discovered expert evidence that could show the additional test result was not probative of impairment and should have been excluded along with all other marijuana evidence. Plaintiff could not have reasonably presented the evidence at trial for two reasons. First, plaintiff did not discover much of the evidence (academic literature showing that the urine test could not be used to judge impairment). Second, the expert evidence Plaintiff discovered in the course of trial was discovered only after the time when it would have made a difference, which was in the hearing on Plaintiffs motion in limine.”
From plaintiffs motion, we learn that the purported “newly discovered” evidence was scientific literature. Plaintiff does not tell us in his motion whether the “newly discovered” literature was discovered during or after trial, only that it was discovered “after the time when it would have made a difference.” We turn then to plaintiffs expert and his affidavit in support of plaintiffs motion for a new trial for more answers. Our first task is to identify what scientific literature *448plaintiff claims to be “newly discovered.” In that vein, Brady’s affidavit is careful to aver that his survey of the literature occurred “[d]uring and after [plaintiffs] trial.” Importantly, Brady never expressly identifies which scientific articles he claimed to have discovered post-trial. Our own review of the record reveals that Brady refers in his post-trial affidavit to only one other specific source of scientific literature not mentioned in his affidavit in support of plaintiffs motion in limine made before trial or made available to him by Griffin during trial. That study was conducted by the United States Center for Disease Control and Prevention, and it was published in 1983. Perhaps it can be inferred from the record that that study constitutes the “newly discovered” post-trial evidence, but we are left to imagine how its contents differ from the contents of the literature that Brady surveyed before and during trial. Also, in his affidavit in support of plaintiffs motion for a new trial, Brady referred to studies furnished to him through Griffin’s file, but those studies were furnished to Brady during trial after Griffin finished testifying, and Brady testified regarding them in his rebuttal testimony that followed Griffin’s testimony before the trial ended. Finally, in light of Brady’s assurances to the court pretrial and to the jury that no scientifically accepted method of calculating impairment based on the available data existed, we are inclined to take him at his word that he had undertaken a survey of the existing literature before he made those assertions.
Even if we assume that plaintiff made an adequate identification in his motion of what he claims to be “newly discovered” evidence, there is yet another requirement that plaintiff has not met under ORCP 64 B(4). Based on the purported discovery of newly discovered scientific literature, Brady proposes to testify at a new trial that Griffin’s opinion that the marijuana consumed by plaintiff impaired him at the time of accident has no scientific validity. However, he gave the same opinion in his trial testimony; thus, the issue is whether there is anything new about Brady’s testimony offered in his post-trial affidavit. The dissent argues that Brady’s testimony is “newly discovered” because “Brady gave only negative testimony at trial—that he was unable to find relevant studies—while after the trial he was able to show *449positively that there was no scientific basis for using the quantitative test to indicate impairment.” 195 Or App at 468 (Wollheim, J., dissenting). The dissent also asserts that Brady “did not assert [at trial] that Griffin’s opinion was without a scientific foundation or that it was impossible to determine impairment from a quantitative measurement of metabolites rather than of total cannabinoids.” Id. at 473.
Additionally, the dissent lists five factual statements in Brady’s post-trial affidavit that it says “are in neither the pretrial affidavit nor Brady’s testimony at trial.” Id. at 474. They are, according to the dissent: (1) the fact that excretion of marijuana metabolites into the urine varies dramatically among individuals; (2) because of such variations, it is not possible to correlate a quantitative test of metabolites in urine with the amount of active metabolites in a person’s blood at a particular time; (3) there is no correlation of the active ingredient of marijuana with impairment that can be made in the way that blood alcohol content can be correlated with impairment; (4) the United States Center for Disease Control and Prevention advised in 1983 that a urine test alone cannot indicate impairment; and (5) “[g]iven those facts, together with the lack of any study that would enable an expert to determine impairment from a measure of total cannabinoids, Brady was highly doubtful that there was any scientific method that could lead to an informed conclusion about impairment based on a measure of total cannabinoids in a urine sample.” Id. at 474-75. The dissent concludes that “[t]he post-trial affidavit, thus, contained a substantial amount of new information, most significantly that it is not possible to use even a urine test for the total metabolites to determine impairment.” Id. at 475.
Our review of the record indicates that it does not support the dissent’s assertion that Brady based his post-trial opinion on “new” information. In fact, Brady testified at trial that the quantitative test of plaintiffs urine “clearly * * * does not” measure how much of the active ingredient was ever present. That is the identical assertion that plaintiff made in his motion for a new trial when he said that “the urine test could not be used as a reliable gauge of impairment * * *.” Moreover, Brady was also asked in his testimony at trial about the scientific literature in Griffin’s file and *450whether those articles attempted to connect a quantitative test result with a ‘level of impairment at any particular time.” Brady responded, “No, they don’t.” Then, he was asked whether he was aware of any scientific literature or studies that connect a quantitative test result with level of impairment at any particular time. Brady answered:
“No, I’m not, [plaintiffs counsel]. You’ve asked me this question. I’ve done my best to look around, and I know of no literature, no study that I’m familiar with that correlates the total cannabinoids with the question of impairment.”
In addition, Brady was asked at trial if, in his opinion, an expert in his field could determine with reasonable medical probability from the test result “whether the patient was impaired at some particular time before?” Brady answered, “At a particular time prior to this sample being taken? No, no.” Finally, Brady was asked at trial, “Can you tell from [the test result] how much of that particular metabolite or breakdown product was in the test subject’s urine?” Brady responded, “No. All we know was the total material all together, and this gives us no information about any particular component of that whole big glop.”
In comparison to his trial testimony, Brady averred in his post-trial affidavit:
“I am unaware of, and have not been able to locate, any scientific study that enables an expert to use a measure of total cannabinoids to form an opinion about whether the subject was impaired at some particular prior point in time. Given the problems inherent in judging impairment even from a particular metabolite of active ingredient (as discussed above), and given the inability to distinguish the contribution of each substance included in a measure of total cannabinoids, I am highly doubtful that there is any scientific method that could lead to an informed conclusion about impairment based on a measure of total cannabinoids in a urine sample.”
Later, in his post-trial affidavit, Brady added that Griffin’s opinion “is not an opinion that can be reached through any accepted scientific method of analysis” and that “there is no scientifically accepted method for getting from total cannabinoids in [plaintiffs] urine later that day to *451active ingredients in his blood at the time of his injuries * * * because * * * different people metabolize the active ingredient at different rates and secrete the metabolite in different amounts and at different times.” He explained further in his affidavit,
“Moreover, the measure of carboxy-THC would fail to distinguish use that day that might have caused impairment from use days earlier that could not have caused impairment that day. The result reflected in the test result produced on the day of trial is fraught with the further problem that it is not even a measure of carboxy-THC. It is a measure of total cannabinoids that does not distinguish between active ingredient, carboxy-THC, [or] other metabolites or cannabinoids that do not cause impairment.”
Brady also concluded in that portion of his affidavit that “[n]o accepted scientific method allows such a conclusion “that an opinion as to impairment can be drawn from the measure of total cannabinoids in plaintiff’s urine sample.” Brady also referred in his affidavit in support of plaintiffs motion for a new trial to the literature in Griffin’s file. He opined that
“the literature in Dr. Griffin’s file (1996 and 1998 studies by Huestis, Cone and, in the 1996 study, Mitchell) does not support Dr. Griffin’s claim that a measure of total cannabi-noids in a person’s urine can be used to determine whether a person was likely to be impaired at a particular point in time.”
In sum, the record demonstrates that, if a new trial is granted, Brady’s testimony will be a repeat of his trial testimony. Contrary to the dissent’s assertion that Brady did not assert at trial that there was no scientific basis for using the quantitative test to indicate impairment, Brady testified both at trial and in his post-trial affidavit that he was unable to find relevant studies to support Griffin’s opinion and that an expert in his field could not determine with reasonable medical probability whether plaintiff or any person was impaired at a particular time.
Finally, what does the record show, as ORCP 64 B(4) requires, about whether plaintiff—through Brady—exercised reasonable diligence to discover the “new” scientific evidence before the trial ended? Recall that the trial court found *452that Brady had “shot from the hip” during trial. Brady does not explain in his affidavit why he could not have done the necessary research before the trial ended,9 and the evidence submitted by Brady in his affidavit suggests the contrary inference. The most pertinent fact relative to that issue is that all of the studies on which Brady relies were published in scientific journals many years before the trial in this case. The second most pertinent fact relative to the issue is that Brady represented to the court and the jury during the trial that he had previously conducted a complete survey of existing scientific literature on the subject. Brady’s affidavit in support of plaintiffs motion for a new trial does not respond to those facts or explain why his research done during the trial was incomplete. Although Brady says that, after the trial, he “had time to further review the drug test,” he does not explain what circumstances prevented him from taking the time to do the required research before trial ended.
The chronology of the trial further supports the court’s belief that Brady “shot from the hip.” Plaintiff became aware of defendants’ evidence no later than the morning of June 26, 2001, at the hearing on his motion in limine. The trial also began on that day. The trial ended on July 2, 2001, after a weekend recess. Plaintiff called Brady as his final rebuttal witness on June 29, and Brady testified before the jury that Griffin’s opinion had no scientific basis. Plaintiff never explains in light of those facts why the survey of scientific literature that produced the “newly discovered” evidence *453could not have been discovered before the end of trial through the exercise of reasonable diligence.
Additionally, the dissent’s assertion that Brady was unable to reach a conclusion that there was no scientific support for Griffin’s opinion until after the trial is also contradicted by Brady’s affidavit made before trial. In that affidavit, Brady makes the following generalizations:
“8. It is not possible to determine from the type of urine test that was done for [plaintiff] whether [plaintiff] was mentally or physically impaired at the time of his accident. As noted, the type of urine test that was done for [plaintiff] can only determine whether [plaintiff] ingested some amount of marijuana at some indeterminate time within the previous 72 hours.
“9. It also is impossible to determine from the other evidence regarding [plaintiffs] marijuana use whether [plaintiff] was mentally or physically impaired by marijuana at the time of his accident. No reliable scientific method, and no method commonly accepted in the scientific community, allows such a determination from the facts that are available without also knowing the precise details regarding the potency of the particular marijuana and the precise amount ingested.”10
(Emphasis added.) The dissent posits that Brady was only aware of the screening test performed on plaintiffs urine at the time he made those averments, an assertion, which, of course, is correct. But Brady’s affidavit expressly states that he conducted a scientific investigation that extended beyond ascertaining the limits of screening tests. According to his affidavit, it is impossible to determine from the screening test *454and “other evidence” that plaintiff was impaired at the time of his accident. As a result of his investigation, Brady concludes that “[n]o reliable scientific method * * * commonly accepted in the scientific community * * * allows such a determination from the facts * * *.” Presumably, in light of his sweeping statements about the scope of his investigation, Brady was aware of or should have been aware of, the existence of the kind of quantitative test performed on plaintiffs urine.
Plaintiffs argument to the trial court in support of plaintiffs motion of a new trial further informs the issue of whether Brady acted with reasonable diligence during the trial. Counsel told the court:
“[W]e knew we had been surprised by the additional drug test result, but we didn’t know we had been harmed by it. We didn’t know that given some additional time to consider and analyze this result, to look at the literature and so on, we would have able to conclude, you know, this is really no more probative than anything else in this case, we can still get all this marijuana evidence excluded. We didn’t know that the surprise had hurt us * * *. As time went on, and we heard the other testimony unfold, and we looked at literature in the course of and after trial, our opinion on that issue changed.”
(Emphasis added.) Counsel’s statement tells us that plaintiff made the strategic decision to proceed with the trial on the first day of trial and then, at some later point in time, decided that plaintiff had been harmed by Griffin’s testimony. Taking plaintiff at his word, the earliest that plaintiff could have realized that he had been harmed would have been after Griffin testified on direct examination in the latter stages of trial. Nonetheless, plaintiff does not explain why Brady could not have begun his research on the first day of trial when he learned about Griffin’s testimony and finished any additional research before he testified on rebuttal days later or why plaintiff could not have asked for a continuance to complete his research.
Arnold is again particularly instructive regarding the requirement of “the exercise of reasonable diligence,” as applicable to this case. 320 Or at 119-22. The defendant in that case, after being convicted of sexual abuse of a child, *455appealed and assigned as error the denial of her motion for a new trial under ORCP 64 B(4) based on the discovery of new evidence. At trial, a prosecution witness testified about her background in child development and about statements made to her by the victim regarding the defendant’s alleged inappropriate touching. On cross-examination, defense counsel examined the witness extensively about her educational qualifications. Immediately after the witness testified, the defendant’s investigator contacted the college that the witness said she had attended and learned that the college had no record of her attendance at that institution. Although defense counsel was aware of that information, he did not bring the information to the attention of the trial court, he did not ask for a continuance, and he did not call the investigator as a rebuttal witness. In her motion for a new trial based on newly discovered evidence, the defendant asserted that, after a complete investigation had been completed, it was evident that the witness had lied about her educational background. The trial court denied the defendant’s motion on the ground that defense counsel’s decision not to raise the matter during trial precluded the grant of the motion. On appeal, this court reversed. On review, the Supreme Court reversed our ruling and remanded for the consideration of the defendant’s other assignments of error.
In reaching its decision, the Supreme Court considered the state’s argument that the defendant’s “newly discovered” evidence did not meet the requirements of ORCP 64 B(4) and that, therefore, the trial court had no discretion to exercise and no authority to grant the defendant’s motion for a new trial. Arnold, 320 Or at 121. The court pointed out that, before the case was submitted to the jury, defense counsel had specific information that the college that the witness said she had attended denied that she had ever attended there and that counsel knew how to obtain that evidence through a subpoena. Moreover, defense counsel never asked for a continuance or for the opportunity to issue a subpoena to procure the evidence. The court held that a new trial should not have been granted under those circumstances. It explained:
“This case is a dispute over how much evidence had to be known and had to be usable during trial to make the balance of the evidence not such as would justify the award of *456a new trial. Even if some additional evidence is discovered after trial, it does not justify the award of a new trial if the evidence that was known during trial could have been used during trial for substantially the same purpose as the additional evidence that is not discovered until after trial.”
Id. (emphasis in original).
The circumstances in Arnold parallel the circumstances in this case. Plaintiffs counsel knew of the issue days before the case was submitted to the jury, and plaintiffs expert witness, Brady, like any expert in his field, must have known how to conduct a survey of pertinent scientific literature. Also, as in Arnold, plaintiff never asked for a delay in the trial to procure additional evidence before the case went to the jury. It is evident from his testimony and his pretrial affidavit that Brady believed before and during the trial that there existed no test that correlated the amount of the active ingredients of marijuana in a person’s body with impairment at a particular time. Even if there was some scientific literature discovered post-trial, that literature could not justify the grant of a new trial under ORCP 64 B(4) because Brady used the literature in Griffin’s file and his own knowledge of the subject matter for substantially the same purpose as the “newly discovered” literature would be used in a new trial. In light of the public’s interest in the finality of the judicial process, the trial court was left with no discretion to exercise in this matter under ORCP 64 B(4). We conclude that plaintiffs attempt to satisfy the legal requirements of ORCP 64 B(4) is legally inadequate on the face of the record for each one of the above reasons.
According to the dissent, “the majority’s errors fall into three basic categories. First is its failure to follow the applicable standard of review.” 195 Or App at 476 (Wollheim, J., dissenting). In the dissent’s view of the proper standard of review, we are to resolve all factual issues in favor of plaintiff. Thus, the dissent’s opinion is replete with references about what “the trial court could have found.” See, e.g., id. at 470. In fact, the trial court made no findings of fact.11
*457The dissent also argues that we must defer to the trial court’s exercise of discretion in this case, based on the implicit findings of fact that the dissent attributes to the trial court. However, the dissent misconstrues the nature of the discretion granted to the trial court under ORCP 64 B(4). A trial court has no discretion to grant a new trial under ORCP 64 B(4) unless the legal requirements of the rule are met. “ORCP 64 B(4) is a statute.” Arnold, 320 Or at 119. “[E]vidence that may justify a court in granting a new trial must meet [the requirements set out above].” Id. at 120. The threshold issue in Arnold was whether ORCP 64 B(4) applied to evidence discovered during the trial. After resolving that issue, the Arnold court explained:
“Having held that ORCP 64 B(4) applies to evidence discovered during the trial, we proceed to consider the state’s argument that defendant’s ‘newly discovered evidence’ would not have justified the award of a new trial under ORCP 64 B(4) and, therefore, that the trial court had no discretion to exercise, and, thus no authority to grant defendant’s motion.”
320 Or at 121. The court concluded:
“[T]he post-trial discovery of the latter information does not satisfy the requirement that the evidence must be such as, with reasonable diligence, could not have been discovered and produced at trial.”
Id. at 122. In other words, the determination of whether the requirements of ORCP 64 B(4) are met is not the kind of decision that involves more than one legally permissible choice to be made by the trial court. See State v. Rogers, 330 Or 282, 312, 4 P3d 1261 (2000) (“If there is only one legally correct outcome, then ‘discretion’ is an inapplicable concept.”). Rather, Arnold teaches us that the decision to be made by the court under ORCP 64 B(4) is initially a legal determination about the adequacy of the movant’s grounds for a new trial.
As we recently said in State v. Woodman, 195 Or App 385, 387, 97 P3d 1263 (2004), while the grant of a new trial is reviewed for an abuse of discretion, “to the extent that the *458grant is based on the interpretation of law, we review for legal error.” See also Bennett v. Farmers Ins. Co., 332 Or 138, 151, 26 P3d 785 (2001) (“When the trial court’s order of a new trial is based on an interpretation of the law, we review that order for errors of law.”). Here, because the trial court based its grant of a new trial on its interpretation of the applicable law regarding the admissibility of scientific evidence, the purported discovery violation under ORCP 55 I, and the desire to avoid a malpractice claim against Brady, our standard of review is for errors of law.
The dissent also argues that the issue of whether Griffin’s testimony was admissible scientific evidence and whether the court erred in finding that it would have rejected that testimony at trial if Brady had been able to present the information that he discovered after trial are issues that defendants do not raise on appeal. The dissent’s argument fails to appreciate the express argument made under defendants’ fourth assignment of error and its necessary implications. In that assignment, defendants first assert that “[t]he trial court erred in granting the plaintiffs motion for a new trial because the supplemental opinion of plaintiffs expert is not newly discovered evidence.” That argument clearly raises the issue whether the trial court ruled correctly under ORCP 64 B(4). Next, in its brief on appeal, defendants expressly point to the portion of the transcript previously quoted in this opinion where the trial court states:
“At this point now that the science is in, if the matter was before me prior to trial, unless it was farther developed in a different manner than what’s been submitted in the affidavits and briefs, I would not allow Griffin to testify about the effect of marijuana, because I think it is contrary to established science.”
(Emphasis added.) We cannot decide whether plaintiff is entitled to a new trial under ORCP 64 B(4) without first deciding whether the trial court’s ruling regarding the scientific validity of Griffin’s opinion was correct.12 For purposes of *459this case and the trial court’s ruling, Brady’s “newly discovered” evidence must constitute evidence that makes Griffin’s opinion inadmissible as a matter of law; otherwise, Brady’s testimony amounts to the same evidence that he presented at trial, and plaintiff is not entitled to a new trial under ORCP 64 B(4). Thus, determining the correctness of the trial court’s ruling regarding the validity of Griffin’s scientific opinion, a ruling expressly challenged by defendants in their fourth assignment of error, is a necessary predicate to deciding whether the trial court’s grant of a new trial under the subsection of ORCP 64 B was correct.
Moreover, parties to an appeal cannot prevent us from noticing and invoking the requirements of a statute merely because they have failed to assert its application. Miller v. Water Wonderland Improvement Dist., 326 Or 306, 309, 951 P2d 720 (1998); Burk v. Hall, 186 Or App 113, 118, 62 P3d 394, rev den, 336 Or 16 (2003). Plaintiff can prevail on appeal under ORCP 64 B(4) only if the rule’s requirements are met and its requirements compel us to determine if there exists “newly discovered evidence.” It follows from defendants’ assignment of error that we must necessarily decide whether the trial court’s subsequent reversal of its own evidentiary ruling made during trial was correct.
Finally, the dissent argues that we err because, according to the dissent, we infer improperly that Brady should have been able to find the purported new information during trial and because we impermissibly rely on the statements of plaintiffs counsel to draw that inference. 195 Or App at 476-77 (Wollheim, J., dissenting). Apparently, the dissent’s notion flows from its belief that we are required to draw all factual inferences in favor of plaintiff. Once again, the dissent’s argument is premised on a misunderstanding of the proper standard of review. As stated above, the trial court made no findings nor is there any concrete suggestion in the record that it drew any inferences pursuant to ORCP 64 B(4). Additionally, the burden was on plaintiff to make an adequate showing in the trial court that he had fulfilled all the legal requirements under the rule. In fact, for the reasons mentioned previously, plaintiff made no prima facie showing of compliance with the rule’s requirements; that is the point of our references to both Brady’s failure to explain why the *460research could not have been completed before trial and to plaintiffs counsel’s explanation of that failure.
In summary, the trial court granted a new trial premised on three legal rulings: (1) Griffin’s opinion does not constitute valid scientific evidence; (2) ORCP 55 I was violated; and (3) if a new trial is not held, plaintiff may sue Brady for malpractice. A trial court does not have discretion to commit errors of law. It must exercise its discretion within a range of legally permissible choices. None of the above grounds relied on by trial court involves the exercise of discretion. From the time that plaintiff filed the pretrial motion in limine until the arguments were made in support of his motion for a new trial, plaintiff never wavered in his position that the evidence of his marijuana usage and Griffin’s testimony was inadmissible. Indeed, he offered Brady’s testimony at trial on that very issue. In contrast, the concept of “newly discovered” evidence contemplates new evidence discovered post-trial that reasonably could not have been discovered before or during trial with the exercise of reasonable diligence and that is likely to change the result of the trial. It is plaintiff’s burden to demonstrate that the requirements of the rule have been satisfied. In the absence of satisfying the requirements of the rule, he is not entitled to a new trial as a matter of law. That is exactly what occurred here, and the record is clear that the trial court’s reasoning that led it to grant a new trial was predicated on its rulings of law, rulings that are erroneous. Consequently, reversal of the grant of a new trial is required, and the judgment for defendants must be reinstated.
Reversed on appeal; affirmed on cross-appeal.
Defendants raised issues of comparative fault in their pleadings. In its verdict, the jury found that defendants were not at fault in any way that was a cause of damage to plaintiff and, thus, did not reach the issue of comparative fault.
2 Citations to ORCP 55 I throughout this opinion are to former ORCP 55 I (2001). The Council on Court Procedure deleted that statute on December 14,2002. Because the trial in this case occurred in 2001, ORCP 551 was applicable below and is also relevant on appeal.
The court told plaintiffs counsel that it did not feel that counsel had withdrawn the legal challenge to the admissibility of defendant’s scientific evidence when plaintiff withdrew the motion in limine. The court said that, at that point in time, counsel could have argued until he was “blue in the face,” but that plaintiff did not have the information he presented post-trial “because of an irregularity in the process and surprise.” It is inferable from those comments that the trial court was relying on the provisions of ORCP 64 (B)(1) and (3).
As we discuss below, defendants’ failure to give notice of the subpoena is still relevant to whether plaintiff exercised reasonable diligence for the purpose of his motion for a new trial on the ground of newly discovered evidence.
In granting a new trial, the trial court made no ruling under OEC 403.
For instance, with regard to an airplane pilot study relied on by Griffin, plaintiff argues that the study sample was too small, that it did not show that all of the pilots in the study suffered from impairment, that the tasks that the pilots were assigned did not correspond to activities such as snowboarding, that the impairments were minor in nature, and that the dose ingested by the pilots was known while the amount of marijuana ingested by plaintiff and its potency was unknown.
In his affidavit in support of plaintiffs motion in limine, Brady averred, “As noted, the type of urine test that was done for [plaintiff] can only determine whether [plaintiff] ingested some amount of marijuana at some indeterminate time within the previous 72 hours.”
At trial, plaintiff cross-examined Griffin on substantially the same issues raised by plaintiffs expert in his affidavit in support of plaintiffs motion for a new trial.
In his affidavit in support of plaintiffs motion for a new trial, Brady further averred:
“During and after [plaintiffs] trial, I had time to further review the drug test result that was disclosed by Defense counsel on the day of trial. I also had time to review scientific literature and to consult with other experts regarding whether the measurement of total cannabinoids reflected in the newly discovered test result could be used to determine if [plaintiff] was impaired at the time of his injuries. The literature I reviewed included the file of Defendant’s expert, Dr. Kirby Griffin. Based on my additional review, consultation and analysis, I have concluded, for reasons detailed below, that there is no accepted scientific basis for using the test result disclosed the day of trial to determine whether Mr. Mitchell was likely to have been impaired at the time he was injured. As I said in my affidavit in support of Plaintiffs motion in limine (attached as Exhibit 1), the sum of other information available in this case also falls short of what is needed, under any scientifically accepted method of analysis!,] to form an opinion about whether [plaintiff] was impaired by marijuana use at the time he was injured.”
Additionally, Brady averred in his pretrial affidavit:
“6. The active ingredient in marijuana, Delta 9 THC, typically dissipates from the blood stream within four hours of ingestion or less, after which the subject is essentially unimpaired by it. The effects of Delta 9-THC are strongest within the first half-hour of ingestion and then taper off rapidly after that. Depending on the potency of the marijuana and the amount ingested, the subject may be unimpaired by it in as little as one to two hours.
“7. The urinalysis test that was used for [plaintiff’s] toxicology report, which is called a ‘presumptive screening* or ‘qualitative’ test can only determine whether the subject ingested marijuana at some indeterminate time within the previous 72 hours. The test cannot determine the amount of marijuana ingested or whether the subject was impaired by marijuana at the time of the test or at any particular time before or after the test.”
Nor would it had been permissible for the trial court to have weighed the evidence by finding Brady’s post-trial affidavit more persuasive than Griffin’s *457post-trial affidavit. For instance, the issue of the admissibility of Griffin’s testimony is solely a question of law.
Because the trial court focused on the admissibility of the evidence about marijuana in deciding whether to grant a new trial, the issue raised by the dissent is not an issue about preservation in the trial court but whether we should address an element of ORCP 64 B(4) when defendants did not directly address it on appeal. As we have said previously, no correct legal analysis can be made in this case without determining whether Griffin’s testimony was admissible at trial.