WOLLHEIM, J., dissenting.

The majority reverses the trial court's grant of a new trial in this case on an issue that defendants did not raise on appeal, and it decides that issue incorrectly. None of the issues that defendants do raise justifies reversal. This court should affirm the trial court's order.

I begin with the facts, both those involved in plaintiff's claim and those that occurred during the trial and the post-trial proceedings. Plaintiff was injured while snow-boarding at a ski area that defendants operate on Mt. Hood. He snowboarded into a wooded area between two ski runs, Whoopee and Reservoir Hill, he fell into Reservoir Creek, which runs through the wooded area, and was seriously injured. Plaintiff testified that he entered the wooded area at a nonprotected portion of the Whoopee side rather than at the fully protected Reservoir Hill side. In his complaint, he alleges 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." At trial defendants denied that plaintiff entered the area from the Whoopee side and argued, based in part on the evidence of snowboard tracks, that he actually entered from the Reservoir Hill side. No witness saw plaintiff enter the area. The jury answered "No" to the following question: "Were defendants at fault in one or more ways alleged by the plaintiff, and, if so, was such fault a cause of damages to plaintiff?"

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. That evidence included the results of a quantitative test of plaintiff's urine after the accident that showed 603 nanograms of cannabinoids per cubic centimeter. According to defendants' expert, Dr. Griffin, that level of cannabinoids indicated that plaintiff was impaired as a result of the marijuana. During discovery, plaintiff had requested all of his medical records from the appropriate providers. He had received a copy of the original screening test of his urine, which merely showed the presence of marijuana metabolites, not their amounts. 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. 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 an expert who worked at the laboratory that performed it. They then 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.

Plaintiff filed a motion in limine to exclude evidence of his use of marijuana. He relied on the opinion of his expert, Dr. Brady, that a positive result on a screening teest could not show that plaintiff was impaired at the time of his injury. During the argument on the motion in limine on the first day of the trial, defendants revealed the existence of the quantitative test. That revelation took defendants and Brady by surprise. Because he had not conducted research on the issue, Brady was not able at that time to state that an expert could not conclude that plaintiff was impaired at the time of the accident. Plaintiff therefore withdrew the motion in limine, and the evidence was admitted at trial over plaintiff's objections that defendants had not shown that it was sufficient to indicate impairment. Defendants used the evidence 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 plaintiff's, rather than defendants', negligence.

During and after the trial, plaintiff investigated the circumstances under which defendants received the quantitative test report, and Brady conducted research into its scientific significance. Brady was ultimately able to determine that there was no scientific basis for concluding that the total amount of cannabinoids in plaintiff's urine, which reflected the total material from the marijuana smoke rather than only the psychoactive component and its metabolites, could indicate whether plaintiff was impaired at the time of his injury. Plaintiff moved for a new trial on the ground that the trial court should not have admitted evidence concerning his marijuana use because there was no scientific basis for determining from the evidence that plaintiff was impaired.

ORCP 64 provides that a trial court may set aside a verdict and grant a new trial on grounds that include:

"B(1) Irregularity in the proceedings of the court, jury or adverse party, or any order of the court, or abuse of discretion, 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."

Plaintiff moved for a new trial on each of those grounds. The trial court granted the motion without indicating the ground on which it relied. In doing so, it found that the evidence that plaintiff presented to support the motion showed that Griffin's testimony about the effect of marijuana was contrary to established science. The court also found that the reason that plaintiff did not present that evidence before trial was in part the conduct of the hospital, in part the conduct of Brady, and in part the conduct of defendants in not following the proper subpoena procedure for obtaining the report. It concluded that the evidence could have had a significant effect on the trial, in part because it could have led the jury to find that plaintiff's marijuana use, rather than anything that defendants did, was the cause of plaintiff's injury and in part because inappropriate references to marijuana would unfairly impair plaintiff's right to a fair determination of the case.

Whether to grant a motion for a new trial is a discretionary decision for the trial court. See Ertsgaard v. Beard, 310 Or 486, 496, 800 P2d 759 (1990); State v. Miller, 167 Or App 72, 75-76, 1 P3d 1047, rev den, 330 Or 553 (2000). We will affirm the trial court's exercise of its discretion to grant a new trial "if any of the grounds argued in support of the motion is well taken and the error is prejudicial. Williams v. Laurence-David, 271 Or 712, 718, 534 P2d 173 (1975)," Schacher v. Dunne, 109 Or App 607, 609, 820 P2d 865 (1991), rev den, 313 Or 74 (1992). A party seeking to reverse such an order must show that none of the grounds specified in the motion is valid, and we give the trial court every benefit of the doubt in that regard. Hightower v. Paulson Truck Lines, 277 Or 65, 69, 559 P2d 872 (1977). At least to the extent that the trial court based its decision on the ground of newly discovered evidence, we defer to its explicit and implicit factual findings. See OEC 104.

Defendants raise several issues that, if correct, would require reversing the trial court's order. Before discussing my disagreements with the majority's analysis, I first consider those issues. Defendants first assert that the evidence of plaintiff's marijuana use was relevant only to defendants' affirmative defense of comparative fault. If so, the jury's finding that defendants were not negligent means that it never reached the issue of comparative fault. In that case the evidence of plaintiff's marijuana use would be harmless as a matter of law if it was relevant only to defendants' affirmative defense. See, e.g., Hatfield v. Gracen, 279 Or 303, 311, 567 P2d 546 (1977) (failure to give instruction on the plaintiff's contributory negligence harmless when jury found the defendant not negligent); Stiles v. Freemotion, Inc., 185 Or App 393, 400-02, 59 P3d 548 (2002), rev den, 335 Or 504 (2003) (erroneous instructions on inherent risks of skiing in action against maker and seller of snowboard related only to the plaintiff's comparative fault and were harmless); Wohlers v. Ruegger, 58 Or App 537, 541-42, 649 P2d 602 (1982) (only possible prejudice from admission of complaint in another case related to the plaintiff's comparative negligence, and the jury found that the defendant was not negligent).

The problem with defendants' argument is that, as their own argument to the jury shows, the evidence of plaintiff's marijuana use was directly relevant to the fundamental question of whether defendants' negligence was a cause of plaintiff's injuries. If the jury found that, as plaintiff testified, he entered the wooded area from the Whoopee side at a point where there were no ropes or other warnings, it might well have found defendants negligent in a way that harmed plaintiff. However, if it found that he entered from the Reservoir Hill side, where there were ropes the entire way, such a finding was impossible under plaintiff's specification of negligence. The only relevant evidence in plaintiff's favor on that crucial point came from his own testimony. Thus, it was important for defendants to give the jury a reason to discount that testimony as unreliable.

At the very close of his argument to the jury, defendants' attorney told the jury:

"I'm sure that the plaintiff truly believes what he says. We're not saying he's a liar or he's not, you know, some bad person. I'm sure that's what he believes. But what we don't — all we can do is look at this scene. There are no physical facts that confirm what he says. We know — it's up to you to evaluate the evidence from the expert — but we know that he smoked marijuana that morning, and we know there's evidence that he was impaired. We don't — you know, maybe that affected his perception, his time, distance, vision and so forth. Maybe he doesn't, because of that, because of whatever reason, doesn't have a good recollection of what happened."

(Emphasis added.) Defendants, thus, asked the jury to infer that plaintiff's use of marijuana could have affected his ability to know what he was doing and to remember what he did, and, thus, could have led him to believe something that was not true. The jury could conclude from the quantitative test, with the significance that Griffin gave it in his testimony, that plaintiff's ability accurately to remember what happened was impaired. Thus, the evidence of the quantitative test, together with the meaning that Griffin gave it, could have affected the verdict in a way that the instructions and evidence at issue in the cases on which defendants rely did not. Defendants' first assignment of error is not a basis for reversing the grant of a new trial.

Defendants next assert that plaintiff failed to preserve any error because he withdrew his motion in limine rather than asking for a continuance when defendants informed the court of the second urine test. Defendants argue that plaintiff thereby waived any claim of surprise. They also point out that plaintiff failed to object to the admission of the test result on the grounds that he raised in his motion for a new trial. The difficulty with defendants' argument is that plaintiff did not need to show that the trial court erred during the trial in order to seek a new trial on the grounds that he raised. There was thus no claimed error for him to preserve.

What a party must do during trial in order to move for a new trial afterwards varies depending on the ground on which the party relies. None of the grounds on which plaintiff relies has an implicit or explicit preservation requirement, and it would be inconsistent with at least some of them to impose such a requirement. For example, a claim of newly discovered evidence under ORCP 64 B(4) is necessarily based on evidence that the party discovered after the trial had ended or, at the least, could not have presented during the trial. It is usually impossible to preserve that ground for a new trial during the trial itself. In contrast, the two grounds for a new trial on which plaintiff did not rely both require preservation, either implicitly or explicitly, because they involve actions that occurred at the trial and that could be grounds for an appeal. A motion under ORCP 64 B(5), based on "[i]nsufficiency of the evidence to justify the verdict or other decision, or that it is against law," implicitly requires a previous motion for a directed verdict or a peremptory instruction raising the sufficiency issue. Arena v. Gingrich, 305 Or 1, 8 n 1, 748 P2d 547 (1988); Edward D. Jones Co. v. Mishler, 161 Or App 544, 564-66, 983 P2d 1086 (1999). A motion under ORCP 64 B(6), based on "[e]rror in law occurring at the trial and objected to or excepted to by the party making the application," expressly requires that the error be preserved. Because plaintiff did not rely on those grounds, and because he does not assert — and does not need to assert — that the trial court erred during the trial, he did not have to preserve any alleged error.

It is true that a party that is aware during trial of one of the grounds for a new trial that is listed in ORCP 64 B(1) to (4) 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 unfavorable. See, e.g., Turman v. Central Billing Bureau, 279 Or 443, 450, 568 P2d 1382 (1977) (trial court did not err in denying defendant's motion for new trial when defendant had ability during trial to learn from its own files of alleged juror misstatements but did not raise issue until after verdict). However, nothing in the record suggests that plaintiff speculated on the outcome in this case. The trial court expressly stated that plaintiff did everything possible to raise the issues on which he relied in his motion for a new trial; according to the court, doing more would have verged on being obstructionist and unprofessional.

ORCP 64 B(3), which permits the trial court to grant a new trial because of accident or surprise that ordinary prudence could not have guarded against, does have a kind of preservation requirement when the issue is surprise. The general rule is that a party that is surprised at trial may not use that surprise as a basis for seeking a new trial unless the party moved for a continuance to provide an opportunity to respond to the surprising event. See State v. Gardner, 33 Or 149, 152-53, 54 P 809 (1898); see also Arbogast et al v. Pilot Rock Lbr. Co., 215 Or 579, 594-95, 336 P2d 329 (1959) (applying principle to motion to reopen case in suit in equity). Plaintiff did not seek a continuance and, therefore, was not entitled to a new trial on the ground of surprise.

Defendants also 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 (2001) was irregular or constituted misconduct, thus implicating both ORCP 64 B(1) and (2). I agree with the majority that there was no irregularity and that defendants did not commit misconduct, although I do not necessarily agree with all of its analysis.

The decisive question, then, is whether the trial court correctly granted a new trial on the ground of newly discovered evidence. Defendants argue that the supplemental opinion that Brady gave concerning the significance of the quantitative test was not newly discovered evidence under ORCP 64 B(4). Defendants point out that Brady testified at trial that he had been unable to find any studies that correlate total cannabinoids with impairment. They also argue that plaintiff did not act with reasonable diligence in seeking the quantitative test before trial. The nature of the majority's analysis requires me to discuss those points, and the facts on which they are based, at some length. In short, the problem with defendants' first argument is that Brady gave only negative testimony at trial — that he was unable to find relevant studies — while after the trial he was able to show positively that there was no scientific basis for using the quantitative test to indicate impairment. The problems with their second argument include that, before trial, the appropriate person in the records department at the hospital expressly denied that there was a quantitative test and that the evidence permitted the trial court to find that Brady worked diligently to determine the meaning of that test once he learned of it but did not complete his research until the trial was over.

Brady described the relevant events in his affidavit. He first learned of the quantitative test when defendants referred to it during the argument on plaintiff's motion in limine. When they represented to the court that the quantitative test indicated a level of 603 nanograms in plaintiff's urine, Brady believed that that amount referred to the total metabolites, not to all cannabinoids including inert substances, because most laboratories seek to measure only the metabolites of the active ingredient of marijuana when they perform quantitative tests. Based on that belief, he initially concluded, without time to conduct significant research, that reasonable experts could disagree on whether the test result showed probable impairment.

Brady obtained a copy of the test result during the lunch hour recess but was unable, before the hearing on the motion in limine resumed, to determine the relationship between the total cannabinoid level that the test showed and the levels of active ingredients. As a result, he told plaintiff's attorneys that he could not testify that there was insufficient information from which an expert could conclude that plaintiff was impaired. During and after the trial, he continued to review scientific literature and consulted with other experts concerning the meaning of the quantitative test. Based on that research, Brady ultimately concluded that there is no scientifically accepted basis for using the test result to determine whether it was likely that plaintiff was impaired at the time of the injury. If he had had the test result a reasonable time before trial, he would have been able to examine it and the relevant literature without the crisis atmosphere that the surprise disclosure created, and he would have reached his conclusions before trial rather than afterwards.

The science on which Brady relied involves the nature of marijuana and the way that the body processes its active ingredient. In summary, his review of the literature led him to conclude that there is no scientifically accepted method for judging impairment even from a measurement of metabolites of the active ingredient. There are significant individual differences in the speed and other characteristics of the metabolism of the active ingredient and in the amount that is available in any particular sample of marijuana. Brady was unable to find any scientific study that would allow someone to use a measure of total cannabinoids, rather than metabolites of the active ingredient, to determine impairment. For the reasons that I describe later in this opinion, the trial court could conclude, based on Brady's post-trial affidavit, the studies that accompanied it, and on Griffin's response, that there was no scientific basis for the opinion that Griffin gave.

The majority appears to hold that Brady's post-trial opinion was not newly discovered evidence, although it is not entirely clear on this point. At times it appears to confuse the question of the admissibility of Griffin's testimony at trial with the question of whether Brady discovered new evidence after trial. That confusion is reflected in the majority's decision to discuss the admissibility of Griffin's testimony based primarily on the evidence at trial, when the trial court ultimately rejected it because of the newly discovered evidence that plaintiff presented after trial. In order to avoid that confusion, I will first explain why the post-trial evidence was newly discovered. After doing so, I will then discuss the trial court's decision to grant a new trial based on that evidence.

The majority denies that Brady reached an opinion after trial on the basis of full research that was substantially different from what he was able to say before the trial ended. Rather, the majority argues that Brady either did or should have known before the end of the trial substantially everything that he described after trial. In order to respond to the majority's arguments, I will describe the development of Brady's opinion from before the trial to his final conclusion after the trial was over. The trial court could have found, contrary to the majority's position, that Brady exercised reasonable diligence throughout his research. The majority also does not recognize the crucial aspect of Brady's post-trial opinion in the trial court's judgment, which was that it deprived Griffin's evidence of scientific support and made that evidence inadmissible. Thus, Brady's post-trial opinion does not simply contradict Griffin's opinion concerning the weight to give the quantitative test in determining whether plaintiff's use of marijuana impaired him at the time of his injury. Rather, Brady's post-trial analysis, and Griffin's inadequate response, permitted the trial court to conclude that the jury should not have heard anything whatever about plaintiff's use of marijuana. The trial court could have found that nothing that Brady said during trial had that effect.

Brady gave three opinions during the course of the trial and post-trial proceedings. His first opinion, which is contained in his pretrial affidavit, applied only to the screening test, not to the quantitative test; he did not know about the quantitative test when he executed that affidavit. Because a screening test is fundamentally different from a quantitative test, Brady's first opinion is largely irrelevant to the validity and admissibility of the quantitative test. His second opinion, which is contained in his trial testimony, described the problems with using the quantitative test that he had been able to identify at that time. His final opinion, which is contained in his post-trial affidavit, relied on evidence that he did not use (and, thus, that the court could find he had not yet discovered) at trial and, for the first time, explained why Griffin's opinion about the quantitative test was without scientific basis.

Before the trial, both plaintiff and Brady reasonably relied on the hospital's assurance that the only test that it had conducted was the original screening test. A screening test simply determines that metabolites of the active ingredient in marijuana are present in the urine; it does not attempt to determine the amount of those metabolites, of the active ingredient, or of other cannabinoids. Brady's pretrial statements applied only to that screening test. Thus, in his affidavit in support of plaintiff's motion in limine, Brady concluded that it was not possible to determine "from the type of urine test that was done for Mr. Mitchell" — that is, from the screening test — whether plaintiff was mentally or physically impaired at the time of his injury. He pointed out that the screening test could determine only whether a person ingested marijuana within the previous 72 hours. It could not determine whether the person was impaired at the time of the test or at any other particular moment. Brady then added that it was also impossible to determine from the other evidence regarding plaintiff's marijuana use whether he was mentally or physically impaired at that time.

The majority quotes those and other paragraphs of the pretrial affidavit without recognizing that they refer only to the screening test and other information that was available before trial; they have nothing to do with Brady's later conclusions concerning the quantitative test. Indeed, Brady's statements in his pretrial affidavit were contingent on his belief that no quantitative test existed and that it was too late to perform one. His pretrial affidavit, thus, showed only that the screening test and other available information were insufficient to determine plaintiff's impairment; it said nothing about the usefulness of a quantitative test for that purpose. For those reasons, the pretrial affidavit does not detract from the trial court's finding that Brady's post-trial opinion concerning the quantitative test was newly discovered evidence.

An example of the majority's misunderstanding of the pretrial affidavit is its discussion of paragraph 9. In that paragraph Brady first stated that it was not possible to determine from the other evidence (that is, from the evidence other than the screening test) whether plaintiff was mentally or physically impaired at the time of the accident. He then added, in a sentence that the majority italicizes:

"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."

Quoted in 195 Or App at 453 (emphasis in majority). The majority reads that sentence as stating that there is no test to correlate impairment with the amount of active ingredient in a person's urine and suggests that Brady should have been aware of the quantitative test when he made it. Two fundamental things about that quotation show that the majority is wrong. First, Brady emphasized the inability to determine impairment "from the facts that are available" — that is, from the facts as he knew them at the time of the affidavit, before he learned of the quantitative test. His affidavit did not question the possibility of correlating impairment with the amount of active ingredient, if that had been known. Second, Brady suggested that knowing the potency of the marijuana and the precise amount ingested would make it possible to determine impairment. However, in his post-trial affidavit he indicated that it is not possible to correlate the amount of active ingredient in the blood with impairment in the same way that it is possible to correlate the amount of alcohol in the blood with impairment. Thus, Brady's subsequent research led him to a conclusion that was different from what he had suggested before trial. Contrary to the majority's suggestion, the quotation indicates that Brady did not know before trial what he discovered afterwards.

When Brady learned of the existence of the quantitative test, he in effect told plaintiff's lawyers that the information in his pretrial affidavit did not apply to that test and that he would have to do additional research. He conducted that additional research during and after the trial. His first discussion of what he found came three days later when he testified as the last witness in the trial. That testimony was based on what he had discovered to that point; in effect, it was a progress report.

The focus of Brady's testimony was explaining the difficulty of using a measurement of total cannabinoids to determine impairment. He explained that total cannabinoids include all of the material in the marijuana plant, not simply the unknown small portion that is the active ingredient, and pointed out that the research on which Griffin relied in his testimony did not measure total cannabinoids. When plaintiff's lawyer asked Brady if he was aware of any studies that connected the measurement of total cannabinoids to a person's level of impairment at a particular time, he stated that he had done his best to look around and knew of no study that correlated total cannabinoids with the question of impairment. He did not testify that studies showed that it was impossible to make that correlation. He also stated that an expert could not determine from the test result whether a person was impaired at a specific time before the measurement was taken.

Brady's testimony, thus, was limited in significant respects. He simply disagreed with Griffin about the meaning of the quantitative test of total cannabinoids. His primary point was that a measurement of total cannabinoids says little or nothing about the amount of the active ingredient or its metabolites or about the person's impairment at a specific time in the past. He did not assert 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.

Brady's final conclusions came in his post-trial affidavit, which plaintiff filed in support of his motion for a new trial. That affidavit contained important statements that Brady had not previously made and that were essential to the trial court's decision to grant the motion. The trial court could infer that, if Brady had known during trial what he said in his affidavit, he would have included those things in his testimony; it could therefore infer that Brady did not reach the crucial conclusions until after the trial was over. In the affidavit Brady, explained that, "[d]uring and after Mr. Mitchell's trial," he reviewed the quantitative test result, reviewed scientific literature, and consulted with other experts about whether it was possible to use a measurement of total cannabinoids to determine whether plaintiff was impaired at the time of his injury. Brady's crucial conclusion was that "there is no accepted scientific basis for using the test result * * * to determine whether Mr. Mitchell was likely to have been impaired at the time he was injured."

The post-trial affidavit includes several factual statements that are in neither the pretrial affidavit nor Brady's testimony at trial. The trial court could find that they are, at least in part, the result of his post-trial research: (1) The timing and level of the excretion of marijuana metabolites into the urine varies dramatically among individuals. (2) Because of those variations it is not possible to correlate even a quantitative test of metabolites in the urine with the amount of active ingredient in a person's blood at some previous time. (3) Even if it were possible to correlate a urine test for the metabolite with the amount of active ingredient in the blood at a particular time, it would still be necessary to correlate the amount of the active ingredient with impairment in the way that the amount of alcohol in the blood can be correlated with impairment. (4) The United States Centers for Disease Control and Prevention, referring to tests for metabolites, has advised that a urine test alone cannot indicate performance impairment or assess the degree of risk associated with a person continuing to perform tasks. (5) Given 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.

Brady's post-trial statements thus went significantly beyond his skepticism in his testimony at trial about using a test of total cannabinoids — the great majority of which are inert — to determine impairment. As a result of his post-trial research, his skepticism about Griffin's testimony had changed to certainty that it was without scientific basis.

In his post-trial affidavit Brady also relied on the information that he had originally described in his pretrial affidavit and in his trial testimony. He concluded, based on all of the information that he described, that the quantitative test of total cannabinoids failed to provide a scientifically valid basis for forming an opinion about whether plaintiff was impaired at the time of his injury. He also described his reasons for believing that Griffin's analysis was totally lacking in any scientific basis. In doing so he repeated that there is no scientific method for getting from the amount of total cannabinoids in plaintiff's urine at a later time to the amount of active ingredient in his blood at an earlier time. However, he now emphasized that even a measure of the total metabolites would not be a basis for a reliable estimate of the amount in plaintiff's urine. Finally, he described why the literature in Griffin's file did not support Griffin's opinion.

The 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 total metabolites to determine impairment. That new information was crucial to Brady's opinion that Griffin's testimony was without scientific foundation. Brady's opinion on that point, in turn, was the basis for the trial court's conclusion that it should have excluded Griffin's testimony, along with all other evidence of plaintiff's marijuana use, from the trial. And that conclusion, finally, was the fundamental reason that the trial court granted the motion for a new trial. The trial court could properly have found that Brady did not discover, and in the exercise of reasonable diligence could not have discovered, that new information before the end of the trial.

The majority discusses much of the evidence that I have described but places a different significance on this evidence. The majority's errors fall into three basic categories. First is its failure to follow the applicable standard of review. Because the trial court granted plaintiff's motion, our standard of review requires us to resolve all of those factual issues in favor of plaintiff. The majority, however, finds the facts itself without regard to whether the trial court could have found different facts. It does not recognize that, in order to hold that the trial court erred in determining that Brady's post-trial opinion constituted newly discovered evidence, we must be able to conclude that there was no evidentiary support for that determination.

Second, the majority appears to argue that, because the scientific research on which Brady ultimately relied existed in published form before the trial, his failure to find it before the end of the trial is in itself proof that he did not exercise reasonable diligence in seeking it. Nothing in the record supports the majority's assumption that the mere fact that a study is published means that an expert should be able to find it instantaneously, immediately distinguish it from all other possibly relevant studies, examine its methodology and results, and thereupon describe its precise significance to the issue at hand. There is no rule of law that establishes a reasonable time for completing those tasks, and there is no evidence that the time that Brady took was unreasonable. The development of Brady's views in itself permits the finding that he continued to discover additional information during the period between when he learned of the existence of the quantitative test and when he prepared his post-trial affidavit. It also permits the finding that his decisive conclusions did not come until after the trial had ended. On this record, that is sufficient to support a finding that he acted with reasonable diligence.

Finally, the majority treats statements that plaintiff's attorney made during the trial as showing that the evidence that Brady presented after the trial was not newly discovered. However, the attorney's statements are argument, not evidence. Plaintiff's attorney hoped to convince the trial court of his position based on the evidence that was then in the record. The trial court, however, rejected those arguments at the time, thus indicating that it believed that there was insufficient evidence to support them. Plaintiff discovered the evidence that convinced the trial court only after the trial ended; that was when the trial court accepted arguments that it had previously rejected. The fact that the court responded differently to plaintiff's arguments after trial from how it responded during trial indicates that it believed that plaintiff presented new evidence after trial.

The trial court concluded that, if it had had the benefit of Brady's opinion before or during trial, it would not have allowed Griffin to testify concerning plaintiff's impairment and that it would not have permitted any evidence of plaintiff's use of marijuana. It then granted the motion.

In reviewing a decision to grant a new trial under ORCP 64 B(4), we apply the well-established criteria for determining whether to grant a trial based on newly discovered evidence in light of the facts that the trial court could have found. With one minor exception, those criteria have not changed for over a century and are the same under the rule as they were under the former statute. The Supreme Court restated them most recently in State v. Arnold, 320 Or 111, 120-21, 879 P2d 1272 (1994):

"(1) It must be such as will probably change the result if a new trial is granted;

"(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."

(Footnote omitted.) See also Oberg v. Honda Motor Co., 316 Or 263, 272, 851 P2d 1084 (1993), rev'd on other grounds, 512 US 415, 114 S Ct 2331, 129 L Ed 2d 336 (1994) (rule is materially identical to previous statute; relies on decisions under statute to interpret rule); State of Oregon v. Davis, 192 Or 575, 579, 235 P2d 761 (1951) (stating same criteria under predecessor to former ORS 17.610(4)); State v. Hill, 39 Or 90, 94-95, 65 P 518 (1901) (establishing criteria).

Although motions for a new trial on the ground of newly discovered evidence are generally disfavored, Davis, 192 Or at 579, each motion must rest on its own particular facts and circumstances, and the court should grant a new trial if the undisputed facts would probably lead an ordinarily reasonable person to a different conclusion from the one that the jury reached. Watrous v. Salem Brewery Ass'n, 151 Or 294, 302, 49 P2d 375 (1935). With those considerations in mind, I examine the newly discovered evidence on the motion for new trial in light of the applicable criteria.

Brady's opinion that it is not scientifically possible to determine from the quantitative test whether plaintiff was impaired, and the reasoning on which he relied, meet the final three criteria for newly discovered evidence. Whether plaintiff's marijuana use impaired his ability to perceive and remember what happened was material to the issue of whether defendants were negligent in a way that caused him damage. The evidence was not cumulative because there was no other evidence in the record that effectively challenged Griffin's opinion. The testimony that Brady gave during trial was both weaker and qualitatively different; at most it showed a disagreement between experts, not that Griffin's opinion was without scientific validity. Finally, the evidence did not merely impeach or contradict former evidence. Rather, it showed that the former evidence was not admissible and thus should not have been presented at trial.

The second and third criteria relate to plaintiff's diligence in obtaining the evidence. The facts on those points are uncontested. As a result of the hospital's failure to disclose the quantitative test to plaintiff when he asked about it, before trial plaintiff believed that the screening test was the only test in existence. Brady was prepared before trial to testify concerning the evidentiary value of that test. After defendants surprised plaintiff by disclosing the quantitative test, Brady conducted additional research during and after the trial. He ultimately discovered the studies that allowed him to reach the conclusions that he described in his affidavit in support of plaintiff's motion for a new trial. The trial court could find that plaintiff acted with reasonable diligence but was still unable to discover the evidence before or during trial; thus, the court could find that the evidence could not have been used during trial.

These facts distinguish this case from somewhat similar cases involving newly discovered expert testimony in which the Supreme Court affirmed the trial court's decision not to grant a new trial. Marshall v. Martinson, 264 Or 470, 506 P2d 172 (1973), was an automobile accident case. The crucial issue was which driver was in his proper lane at the time of the accident. Some of the evidence on that point concerned whether the defendant's automobile collided with a guardrail before or after hitting the plaintiff's vehicle. Before trial, experts for both the plaintiff and the defendant examined the vehicles with that issue in mind and found pieces of creosoted wood from the guardrail that each claimed supported his particular opinion. After a verdict for the defendant, the plaintiff's expert again examined the defendant's vehicle and found additional evidence that, he asserted, gave further support for his opinion. The plaintiff sought a new trial based on that evidence. Id. at 476. The Supreme Court pointed out that the plaintiff's expert had had every motive and opportunity to discover the evidence in question before the trial. For that reason, the court could not say that the trial court abused its discretion in denying the motion for a new trial. Id. at 477-78.

Arnold was a prosecution for child sexual abuse. The CSD social worker who had interviewed the child and was a primary prosecution witness testified that she had earned an associate's degree at Citrus College in California and that she had audited seven classes at Southern Oregon State College (SOSC). She had not listed those experiences in her employment application, and defense counsel cross-examined her at length concerning the discrepancy. During the trial, defendant's investigators contacted Citrus College and learned that it had no record of the investigator ever having attended it under either her married name or her birth name. The college stated that it would confirm that information only if it were required to do so by a subpoena. The defendant's counsel knew those things during trial but did not bring them to the attention of the prosecutor or the trial court, nor did it make any other effort to introduce them into evidence. After the jury returned a guilty verdict, the defendant moved for a new trial, asserting that the investigator had lied about her qualifications. The defendant pointed to the information from the community college and also pointed out that SOSC had no record of the investigator's attendance at the classes that she described and that the investigator did not even have a high school diploma, as she had claimed on her employment application. Arnold, 320 Or at 113-16.

The trial court denied the motion, emphasizing that the defendant discovered the evidence of the witness's false testimony in the middle of the trial and could have presented it to the jury. Because the defendant learned about the evidence during trial, it should have notified the court and sought a continuance in order to secure the evidence for use at the trial. The court apparently recognized that the defendant discovered the other evidence concerning the witness's background after trial, but it concluded that that evidence would not have probably changed the result. Arnold, 320 Or at 116-17. On appeal, we reversed, holding that the defendant's inability to challenge the witness directly on cross-examination, together with the difficulties involved in obtaining an out-of-state witness during the trial, justified the defendant's failure to seek a continuance to obtain the evidence from Citrus College. State v. Arnold, 118 Or App 64, 69, 846 P2d 418 (1993), rev'd, 320 Or 111, 879 P2d 1272 (1994).

On review, the Supreme Court reversed our decision and affirmed the trial court's judgment. The primary issue that it considered was whether evidence discovered during trial can be newly discovered evidence for the purpose of a motion for a new trial. The foundation of the Supreme Court's opinion was its conclusion that the defendant had in fact discovered the evidence during trial. The Supreme Court held that evidence discovered during trial cannot be newly discovered evidence. It emphasized that a party seeking a new trial must show that the party could not, acting with reasonable diligence, have discovered and produced the evidence at trial. Arnold, 320 Or at 119-20. It held, consistently with the trial court's findings, that the evidence in Arnold was not newly discovered under that rule.

Marshall and this case are similar in that in each an expert discovered additional evidence after the trial. However, in Marshall the expert had a full opportunity to discover the evidence before trial and had every reason to do so. The expert did not conduct a truly diligent search until after the verdict against the plaintiff. In contrast, in this case, despite plaintiff's diligence in conducting discovery, Brady did not know that the quantitative report existed until the very beginning of the trial. As soon as Brady learned about the report, he began doing the necessary research to evaluate its meaning in light of existing scientific principles and studies, but he was not able to complete that research and reach his conclusions until after the trial ended. He acted with diligence that the expert in Marshall did not use. Arnold and this case are similar in that in each the parties began investigating the issues that they raised after trial while the trial was in process. However, in this case Brady did not discover the crucial scientific information until after the trial. After trial, not during it, Brady learned that there is no basis for using a measurement of the metabolite to determine impairment; after trial, not during it, he could say that there was no scientific basis for Griffin's conclusions concerning the quantitative test. Unlike Arnold, in this case Brady did not discover, and could not have discovered, the crucial evidence during trial. When the trial ended, plaintiff still did not know what Brady would discover or when he would discover it. Plaintiff specifically did not know that Brady would conclude that the quantitative test was as inadmissible as was the screening test.

That is what his plaintiff's attorney told the court:

"[W]e knew we had been surprised by the additional drug 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 [been] able to conclude, you know, this is really no more probative than anything else in this case, we can still get this marijuana evidence excluded. We didn't know that the surprise had hurt us. * * * As time went on, and we heard testimony unfold, and we looked at literature in the course of and after trial, our opinion on that issue changed."

(Emphasis added.) The majority quotes this statement but does not understand it. 195 Or App at 454. What plaintiff's attorney told the court is that plaintiff at first did not believe that the surprise had hurt him because he did not believe that he could have gotten the quantitative test excluded even if he had known of it before trial. What changed after the trial was that plaintiff learned from Brady that he could have had all of the marijuana evidence excluded despite the existence of the quantitative test; at that point, and not before, plaintiff knew that the additional drug result had hurt him. Plaintiff could not have used the evidence that he knew during the trial for substantially the same purpose — getting all of the evidence of marijuana use excluded — as he used the evidence that he discovered after trial. That evidence, thus, was newly discovered evidence under Arnold, and the trial court acted consistently with that decision when it granted plaintiff's motion.

The remaining question is whether Brady's opinion meets the first criterion for newly discovered evidence, that it would probably change the result of the case. The foundation of the majority's opinion appears to be its conclusion that the trial court erred in concluding that Brady's post-trial opinion rendered Griffin's trial testimony inadmissible under the rules concerning scientific evidence. Not only is that conclusion wrong, but it resolves an issue that defendants did not raise, that the parties have had no opportunity to brief to us, and that is therefore not before us on appeal. A party that does not raise an issue in its opening brief has waived that issue. See State v. Jones, 184 Or App 57, 60 n 2, 55 P3d 495 (2002). The majority goes beyond the function of an appellate court when it reaches out to decide an issue that the appellant neither raised nor briefed.

"A party may make many arguments in the trial court, in order to ensure that it has raised all issues, but may decide on appeal to focus on those that it thinks are most likely to be successful. Except for errors of law apparent on the face of the record, ORAP 5.45(2), it is not our role as an appellate court to ignore an appellant's choice."

State v. Rivas, 100 Or App 620, 622, 788 P2d 464, rev den, 310 Or 122 (1990).

Defendants made six assignments of error, none of which involves the correctness of the trial court's ruling that Brady's post-trial evidence made Griffin's trial testimony inadmissible. Defendants cited many cases in their opening brief; none deals with evaluating the admissibility of scientific evidence. Plaintiff did briefly discuss the admissibility of scientific evidence in response to defendants' fifth assignment of error and in support of their third assignment of error on cross-appeal, but in both cases the issues were necessarily limited to the evidence at trial.

In defendants' fifth assignment, they asserted that plaintiff's motion for a new trial was actually based on ORCP 64 B(5), which provides for a new trial if the evidence was insufficient to support the verdict. Although under the rule the only issue is the sufficiency of the evidence at trial, plaintiff responded in part by defending the trial court's post-trial exclusion of Griffin's testimony. Defendants did not respond to that point in their reply. In their third assignment on cross-appeal, plaintiff argued that the trial court should have stricken Griffin's testimony during trial. In responding, defendants relied in part on the leading Supreme Court case on scientific evidence, State v. O'Key, 321 Or 285, 899 P2d 663 (1995), in defending the validity of his testimony. Again, they did not attack the trial court's post-trial decision, which was different from its decision during the trial. Even if defendants had done so, their attack would not have been in support of any assignment of error that they made and, thus, there would be on basis for us to consider it.

The majority seems to recognize those facts but argues that, because the trial court ruled on the scientific validity of Griffin's testimony as part of granting a new trial under ORCP 64 B(4), and because defendants assign error to the grant of a new trial under that provision, we cannot decide whether the grant of a new trial is correct without deciding whether the trial court's ruling is correct. 195 Or App at 458. The majority thus suggests that assigning error to a trial court decision automatically raises all issues involved in that decision, whether or not the appellant discusses or otherwise refers to them in its brief. That position is inconsistent with accepted appellate practice, as we explained in Rivas. In Rivas the state appealed an order suppressing evidence. The trial court did not explain the basis for its decision. In our original opinion we held that the trial court erred as to some of the evidence because the officer had consent to be where he was at the time that he arrested the defendant and found that evidence. State v. Rivas, 99 Or App 23, 781 P2d 364 (1989). On reconsideration defendant pointed out that, although the state had made that argument to the trial court, it did not make it on appeal. We therefore reconsidered our original decision, held that we erred in discussing the issue of consent, and affirmed the trial court as to that part of the evidence. Rivas, 100 Or App at 622-24. If, as the majority now holds, a challenge to a trial court ruling necessarily encompasses a challenge to every decision that is a foundation for that ruling, our decision on reconsideration in Rivas — and the normal requirement that a party raise the issues that it wants us to consider under its assignments of error — is wrong. I do not believe that we should lightly make so radical a change in appellate procedure, and I see no reason to do so here.

The majority also suggests that, because ORCP 64 B is a rule of procedure, cases such as Miller v. Water Wonderland Improvement Dist., 326 Or 306, 951 P2d 720 (1998), require use to reach issues that the parties did not raise. Those cases, however, simply hold that the parties cannot, by the arguments that they choose to make, limit our construction of statutes and administrative rules in a way that prevents us from construing them correctly. Nothing about this case involves the construction of ORCP 64 B(4); the construction of that rule is already well established. The issue is, rather, the application of the rule to this case. In that context the normal rule that an appellant must raise an issue before we will consider it applies.

Even if the majority were correct that we must decide an unraised issue, its result is wrong. The majority appears to rely primarily on Jennings v. Baxter Healthcare Corp., 331 Or 285, 14 P3d 596 (2000), in which the court discussed the criteria for evaluating the validity of novel scientific evidence. In Jennings, the trial court rejected the testimony of an expert neurologist who would have testified, based on his evaluation of 45 women with similar conditions, that the plaintiff's neurological disorder was related to her silicone breast implants. The neurologist had not reached any conclusions about the mechanism that caused the condition, nor had he published his conclusions. The Supreme Court held that his testimony was nevertheless admissible because he followed proper scientific techniques in developing it. Jennings has little if anything to do with this case. Griffin did not rely on any research — published or unpublished — that he had conducted in reaching his conclusions. He did not assert that his testimony was based on novel theories. Rather, he relied on his general expertise in the field of drug examination and on several published research studies with which he had not been personally involved. The strength of his opinion depends on the strength of those studies. Rather, the relevant case is O'Key. In O'Key the Supreme Court evaluated the admissibility of the Horizontal Gaze Nystagmus test that an officer had used in determining that the defendant had driven while under the influence of intoxicants. The court took the opportunity to establish general criteria for the admission of scientific evidence. In doing so, it emphasized that "trial courts have an obligation to ensure that proffered expert scientific testimony that a court finds possesses significantly increased potential to influence the trier of fact as `scientific' assertions is scientifically valid." O'Key, 321 Or at 293. The court noted that the United States Supreme Court has referred to this role as a "gatekeeper" function. Id. at 301, quoting Daubert v. Merrell Dow Pharmaceuticals, 509 US 579, 113 S Ct 2786, 125 L Ed 2d 469 (1993). It also held that a trial court must not limit itself to determining whether a reasonable person could conclude that evidence is scientifically valid; it must decide the validity issue itself. Id. at 307 n 29.

In O'Key the Supreme Court discussed the criteria that the Court described in Daubert for the admission of scientific evidence under the Federal Rules of Evidence, which are similar in these respects to the comparable Oregon rules. It noted that the first requirement is that the scientific evidence must be "pertinent to the issue to which it is directed." O'Key, 321 Or at 302. It then discussed the factors that the Court had suggested for determining whether evidence is truly scientific. Id. at 303-05. However, those factors do not come into play until the evidence passes the first requirement, that it be pertinent.

In this case that first requirement is decisive. Brady's post-trial opinion makes it clear that Griffin's evidence is not pertinent to the issue to which it is directed — whether the measurement of the total cannabinoids in plaintiff's urine indicated that he was impaired at the time of his injury. The thrust of Brady's post-trial opinion provides strong scientific grounds for concluding that it is impossible to use that test for that purpose. Griffin's post-trial affidavit supporting his testimony at trial does not confront Brady's evidence. It consists of copies of three research studies on the relationship between marijuana and physical impairment and Griffin's statement, unsupported by any scientific research, that the normal ratio between total cannabinoids and metabolites of the active ingredient is between 6 to 1 and 10 to 1. None of the studies that Griffin cited involves a measurement of either total cannabinoids or metabolites of the active ingredient in the urine, and none suggests a relationship between such a measurement at one time and impairment at another. The studies show that marijuana use can lead to impairment under certain circumstances, but they do not show that those circumstances are comparable to the circumstances in this case.

One study was a National Highway Traffic Safety Administration study that measured impairment in people who received measured doses of the active ingredient in marijuana or of a combination of the active ingredient and sufficient alcohol to bring their blood alcohol content to .04 percent. The test subjects began driving 30 minutes after receiving the drugs. There is no indication that they were tested for the amount of cannabinoids or metabolites in their urine or blood. To the contrary, the report commented that "there is no reliable and readily available laboratory marker for THC impairment as there is for alcohol." This study, if anything, supports Brady's opinion. A second study examined impairment in college students who were heavy users of marijuana — that is, who had used marijuana at least 22 of the 30 days before the test. Although the students had cannabinoids in their urine, there was no attempt to correlate the amounts with their impairment. In any case, there is no evidence that plaintiff's marijuana use put him in the same category — or close to the same category — as the tested students.

The final study involved airline pilots who smoked a known dose of marijuana and then performed various activities on flight simulators. The study found residual effects that, in some pilots, lasted up to 24 hours, although the effects on a number of specific activities often disappeared after four or eight hours. The fundamental problem with the study for the purposes of this case is that it provides no information on whether the level of cannabinoids in plaintiff's urine has any probative value in determining whether his use of marijuana impaired him at the time of his injury. The evidence does not indicate whether the dose that plaintiff received was comparable to the doses that the pilots received, and the study does not indicate the level of cannabinoids or metabolites in the pilots' urine.

For these reasons I would hold that the trial court correctly held that, given Brady's post-trial evidence, and considering what Griffin provided after trial to support his trial testimony, Griffin's testimony was not pertinent to the issues to which it was directed and thus was not proper scientific testimony. The remaining question is whether excluding Griffin's testimony, along with all other evidence of plaintiff's use of marijuana, would have affected the outcome of the trial. In its decision the trial court emphasized the impact that evidence of marijuana would have on the jury:

"I would conclude as a trial judge that you get marijuana into the case, if it shouldn't be there, and it's just such powerful poison that it's going to be impair, substantially impair the plaintiff's right to get a fair determination of the facts of the case."

It therefore granted the motion for a new trial despite some uncertainty about the strength of plaintiff's liability case. The trial court acted within its discretion in reaching that conclusion and granting the motion. The trial court was in the best position to evaluate the effect of the improper admission of evidence of marijuana plaintiff's use on the jury's decision, and I cannot say that its conclusion was unreasonable. Although the court did not expressly state that the result would probably have been different without that evidence, defendants did not ask it to decide that issue expressly. The trial court concluded that the evidence was so prejudicial that the only remedy was to grant plaintiff a new trial. In doing so it exercised its discretion with care and consideration, and I cannot say, in light of the issues as the parties presented them, that it erred in doing so.

Finally, in their sixth assignment of error defendants attack the trial court's pretrial grant of plaintiff's motion for partial summary judgment on defendants' affirmative defense of release. The majority does not reach that assignment. I would reject it, but it is not necessary for me to state my reasons for doing so. As does the majority, I would affirm on plaintiff's cross-appeal.

For these reasons, I respectfully dissent.

Armstrong and Schuman, JJ., join in this dissent.