Experts, Standards of Review, and Meta-Evidence

Garner v. BNSF Railway Co., No. D082229 (D4d1 Jan. 4., 2024)

This is a wrongful death case where decedent’s family claims that exposure to diesel exhaust while working as a railroadman caused the non-Hodgkin’s lymphoma that lead to his death. In the run-up to trial, the Company moved in limine to exclude Plaintiff’s general causation experts for failing to satisfy the Sargon standard.

Plaintiffs put up three experts on this point. Generalizing a bit, each testified that diesel exhaust was an established cause of cancer. They pointed to, among other things, epidemiological studies that showed that the exposure could lead to three to four thousand excess cancers per million people, which is clearly significant. But that was cancer in general. None of the experts, however, pointed to any study that linked non-Hodgkins lymphoma, in particular, to diesel exhaust, or that suggested a dosing that could merit causation. But they testified that, more generally, the mutagenic way diesel exhaust acts on human issue merits a conclusion that it can cause cancers that were no just limited to one specific organ. 

The Company pointed out these apparent gaps in the analysis. But it didn’t provide evidence of its own that experts’ reasoning or methodologies were scientifically unsound.

After tentatively accepting the opinions of Plaintiff’s experts, the trial court ultimately excluded them. It found that the gap between the underlying epidemiological evidence and the ultimate conclusions as to general causation was too broad to be bridged by the experts’ opinions. And without the experts, there was no evidence of causation, and thus the case could not go to trial. Plaintiff appealed.

Before getting to the evidentiary issue, the Court of Appeal discusses the standard of review. It recognizes that rulings on evidence, and the admissibility of expert testimony in particular, are generally subject to an abuse of discretion. But, relying on a number of cases, the court says that when an in limine ruling precludes a whole cause of action, it is treated as a nonsuit and reviewed de novo.

But that’s not entirely right. No doubt, the court pulls in language from cases that say, literally, that a motion in limine ruling that excludes all evidence and therefore resolves a whole cause of action is essentially a nonsuit that gets reviewed de novo. But all the cases the court cites deal with circumstances where a trial court decides a legal issue, which then makes all evidence irrelevant and thereby dooms a cause of action. 

The legal issue could be the interpretation of a statute, a contract or case law. It could also be a determination that there’s just not enough evidence to make it to a jury—itself a legal decision that basically a nonsuit. The cases cited all have these kinds of fact patterns. See Kinda v. Carpenter, 247 Cal. App. 4th 1268, 1285 (2016) (on in limine motion, trial court held that evidence was insufficient to get to the jury); McMillin Companies, LLC v. Am. Safety Indem. Co., 233 Cal. App. 4th 518, 529 (2015) (trial court excluded all contrary evidence on a duty issue based on a legal ruling that rendered the evidence irrelevant); Legendary Inv. Grp. No. 1, LLC v. Niemann, 224 Cal. App. 4th 1407, 1411 (2014) (similar); City of Livermore v. Baca, 205 Cal. App. 4th 1460, 1465 (2012) (exclusion of all evidence on the ground that the plaintiff's theory of liability was fatally defective); Dillingham-Ray Wilson v. City of L.A., 182 Cal. App. 4th 1396, 1401 (2010) (trial court interpreted contract as a matter of law and found that interpretation made evidence irrelevant and thus inadmissible); Fergus v. Songer, 150 Cal. App. 4th 552, 570 (2007) (trial court determined that, as a matter of law, attorney fee agreement was voidable and thus that evidence of damages based on it could not go to the jury). But the standard of review in these cases is de novo because the trial courts are fundamentally deciding questions of law, which always get reviewed de novo.

That, however, not the same thing as when a trial court makes an evidentiary ruling that makes certain evidence inadmissible, which then potentially has the consequence that the plaintiff can’t get to a jury. The ultimate significance of a pretrial ruling on a question of the admissibility of evidence should not change the standard of review. Notably, the court doesn’t cite any cases applying de novo review to the exclusion of a causation expert, even when that exclusion is potentially case dispositive. (This recent one, for instance, certainly didn’t.) 

If the evidentiary question is one normally one which is reviewed for an abuse of discretion—a classic example of which is the admissibility of expert testimony, see Sargon Enterprises v. University of Southern California, 55 Cal.4th 747, 773 (2012)—it should be reviewed under that standard, consequences be damned. Then, whether whatever is left is enough to get to a jury is a legal and that question should get reviewed de novo. But reviewing discretionary decisions de novo just because a plaintiff might lose as a result puts a thumb on the scale in favor of a plaintiff because, especially in cases of causation, excluding expert testimony on causation issues is usually case dispositive, but admitting it is generally not. It is completely arbitrary and nonsensical for a standard of review to change based on whether the trial court’s decision was to admit vs. to exclude. The standard of review should turn on the nature of the decision, not its consequence.

(FWIW, I just realized I digressed at length on this point in a post nearly eight years ago. While my memory is imperfect, my point stands nonetheless.)

In any event, moving on to the evidentiary question, the Court of Appeal drills down to the issue of the kind of inference a scientific expert can permissibly draw from underlying source material. As noted, these experts, relying on evidence of increased carcinogenicity in general, concluded that diesel exhaust could cause the specific kind of cancer that killed the decedent. They supported that conclusion with some more testimony explaining why that was a permissible inference, in their fields of expertise, to draw. Like that the kind of pathology caused by exposure to diesel exhaust—mutagenic damage to cellular level DNA—made it reasonable to conclude that the exposure could cause a bunch of different types of cancer. 

So the Court of Appeal concludes that in the absence of any evidence submitted by the Company establishing that that kind of conclusion was an inappropriate one for an epidemiologist to draw from the underlying data, the trial court abused its discretion in excluding the testimony because the inferential gap was too wide.

This is, admittedly, a hard epistemic task. As David Hume explained a couple hundred years ago in An Enquiry Concerning Human Understanding, you can never definitively prove the answer to a question of causation. All you can really do is observe a set of correlations that are significantly close from which an inference of causation can be drawn. So here, the Sargon question is how close does epidemiological statistical data—itself an observation of correlation—need to be to make a methodologically sound inference that a relationship is causal. And even more specifically, what kind of evidence (or law) validates the soundness of that inference.  

Some more extreme facts can illustrate the question. On one hand, say an expert relies on a study of a large population is exposed to some agent in a specific and measurable way. All or nearly all of them develop some rare disease that is almost never seen in the pubic at large. And there’s nothing else about the exposed group that otherwise meaningfully differs from the public. In that case, provided the methods in which the data were collected were sound, the gap between that data and the inference of a causal relationship between the exposure and the plaintiff’s disease isn’t very big at all.

On the opposite end, say the study of a small population correlates exposure a number of different outcomes, which also occur almost as frequently in the unexposed population, the sample was taken from a population that is atypical in some way, and the plaintiff suffers an outcome that is not among the ones measured in the sample. There, the gap between the data and a conclusion of causation is clearly too wide to stand. The fact that a couple of lactose intolerant people get a tummy aches from eating dairy does not justify an inference that ice cream causes pancreatic cancer.

Easy cases like these at the outer limits can likely be resolved as a matter of law or undisputed fact by well-informed judicial common sense. But there is obviously a wide field of grey area in between. And there, the question of “is this a reasonable inference to draw?” seems itself to be a factual question that could itself be a potential subject of expert opinion: Do professionals in the relevant field, employing appropriate methodologies, and outside of litigation, think that, data A rationally merits the more likely than not inference of a causal relationship?

Those situations can turn on a kind of meta-evidence. That is, evidence that, while potentially irrelevant to the merits, goes to a question of whether other evidence is even admissible. Here, that was, to some degree provided by Plaintiff. Its experts testified why it was reasonable to infer causation of non-Hodgkin’s lymphoma from general cancer data concerning exposures to diesel exhaust. On the other hand, the Company didn’t put in anything to the contrary. So that resolves the appeal.

But what if the Company put in evidence that in the practices in field of epidemiology, the inference drawn by Plaintiff’s expert wasn’t a reasonable one to draw? In that case, it seems to me, under Evidence Code §§ 403 and 405(a), as a condition to admitting the testimony, the trial court would be obliged to decide whether, as a matter of fact, a preponderance of the evidence established that the inference was justifiable or the gap was to big. A trial court should not be able to engage in another round of meta-punting on the basis that that question too is a subject of debate within the field.

Reversed.

Stifling Sargon

Bader v. Johnson & Johnson, No. A158868 (D1d4 Dec. 23, 2022).

Another case about whether exposure to talc causes mesothelioma. This one principally concerns three challenges to plaintiff’s experts. I’m going to focus on the first one.

A disclaimer: I have already explained that I know nothing about, and want nothing to do with, asbestos litigation. I am neither a products liability lawyer, nor do I play one on TV. My only interest here is in the law of evidence. So any facts in this post are based on what I gather from the opinion. I have no other knowledge or expertise. But since this case addresses a really interesting evidentiary issue (and, in my opinion, gets it wrong) I’m going to need to get into a little detail.

First, some terminology. The opinion explains that “asbestos” refers to a group of six minerals, but only when they grow in “asbestiform habit,” which is a certain kind of crystalline structure. It is this structure that apparently makes them conducive to getting stuck in human tissue, which can cause cancer. Talc is not one of the six minerals. But sometimes mined talc can be contaminated with the asbestiform habit of one of the six minerals (i.e., asbestos). And talc can also sometimes occur in an asbestiform habit on its own. But asbestiform talc is not asbestos, because talc is not one of the six minerals.

So, simplifying a little, we have 3 categories: 

(A) Uncontaminated non-asbestiform talc; 

(B) Uncontaminated talc that includes asbestiform talc; and 

(C) Talc contaminated with actual asbestos, whether or not it also contains asbestiform talc. 

The fight, as I gather it, is over whether this expert can say that (B) causes meso. 

Defendant challenges that testimony under Sargon, under which a court is supposed to exclude expert testimony that “is (1) based on matter of a type on which an expert may not reasonably rely, (2) based on reasons unsupported by the material on which the expert relies, or (3) speculative.” The rub here comes down to (1) and/or (2). Because the standard of review is abuse of discretion, the question is whether there was substantial evidence in support of the trial court’s finding that this expert relied on reasonable stuff and drew reasonable conclusions from it.

There are apparently a bunch of monographs put out by the International Agency for Research on Cancer, which is part of the WHO. These mongraphs are meta-epidemiological reviews of other studies, including human studies, animal studies, and mechanistic evidence regarding how chemicals interact with cell chemistry or physiology. 

There are three monographs at issue. The first, published in 1987 (which summarized another 1987 publication) says that there is inadequate evidence that (A) causes cancer. But there is adequate evidence that (C) does. But definitionally, the monograph lumps (B) (asbestiform talc) in with (C) (actual asbestos), so it is ambiguous on that point. 

The second, published in 2010, reviewed the 1987 monograph and read its finding to mean that there was adequate evidence that “talc containing asbestos or asbestiform fibres,” “expressly defining ‘asbestiform fibres’ to include talc growing as fibers in an asbestiform habit,” i.e., (B) or (C), caused cancer. B it did not actually reassess the evidence on this point. Indeed, the point of this monograph was to reassess whether the evidence of carcinogenicity remained inadequate as to (A), which it did.

The third, published in 2012, noted that the 2010 monograph included asbestos-contaminated talc within the talcs it considered to be cancer causing, and agreed that talc containing asbestos should be regarded as carcinogenic to humans. But it never made clear finding either way regarding talc with asbestiform habit that is not contaminated with actual asbestos. Indeed, it recognized that “a separate review of talc containing asbestiform fibres was not undertaken.”

The Court of Appeal reads some inconsistency between the second and third monographs interpretation of the first one, such that the second says (B) or (C) is carcinogenic, while the third says (B) and (C), mixed together, are. And since the trial “court’s gatekeeping role does not involve choosing between competing expert opinions,” the Court holds there was substantial evidence for the expert to rely on to say that there is evidence that (B) causes cancer. Plus there’s some other figments of evidence that suggest that is right, such as some cautionary letters that some doctors wrote to an editor, some uncertain animal studies, and some anecdotal clinical evidence.

The Court notes that Defendants argued that the expert’s opinion was against the great weight of the consensus in the field. But, says the court, that is not a Sargon issue. It is an argument that the expert’s technique is insufficiently well-established in the relevant scientific community. That is, an objection under the old, pre-Sargon test in People v. Kelly, 17 Cal. 3d 24 (1976)! And since Defendant didn’t raise a Kelly objection, it was forfeited.

The Court also finds that Defendants failed to establish prejudice. The expert apparently testified to a second theory that Defendants contested with an expert of their own but didn’t object to, and there was additional testimony from another plaintiff expert that also suggested (albeit collaterally) that fibrous talc causes meso. 

Justice Streeter writes a separate concurrence on this issue. He agrees that this wasn’t a Sargon question. He also agrees that the appropriate objection would have been under Kelly, which was not made. He notes that Kelly applies to “techniques, processes, or theories” that are new. 

He admits that Kelly generally didn’t generally apply to medical causation opinions that did not involve new techniques and that the Supreme Court had previously decline to adopt the more stringent Daubert standard that applies in federal courts. He suggests, however, that post-Sargon the Kelly rule could perhaps examine whether the expert’s theory here is sufficiently “new” that it could be subjected to Kelly scrutiny.

Justice Streeter goes on to discuss a federal assessment of criminal forensic evidence that encouraged the examination of the scientific validity of science based expert opinion, and suggests that those considerations could be incorporated into a Kelly analysis. In particular, he notes that the expert’s opinion here was subject to questions of “foundational validity”—questions that ask not only if a theory is accepted, but also whether it is actually a scientific theory at all, subject to empirical demonstration and observable rates of error.

Affirmed.

Some observations:

First, there’s really not a difference of scientific opinion here that the court needs to resolve. The difference between the way the 2010 and the 2012 monographs describe the 1987 on is a difference in grammar—and not a particularly significant one at that. The court doesn’t need to play junior varsity scientist to know that none of the monographs made any conclusion that asbestiform talc, uncontaminated by actual asbestos, was carcinogenic. The fact that the 2010 monograph, merely discussing the results of the 1987 one, used the word “or” cannot change that.

Second, by creating a scientific controversy where there wasn’t one, the court avoided a core obligation under Sargon:  to “determine whether, as a matter of logic, the studies and other information cited by experts adequately support the conclusion that the expert’s general theory or technique is valid.” Sargon Enterprises, Inc. v. Univ. of S. California, 55 Cal. 4th 747, 772 (2012) (quoting Imwinkelried & Faigman, Evidence Code Section 802: The Neglected Key to Rationalizing the California Law of Expert Testimony, 42 Loyola L.A. L.Rev. 427, 449 (2009)*). 

The question really presented here is: In the practice of medicine and epidemiology, is it appropriate to draw the conclusion that “x causes cancer,” based only upon underlying studies that show “x causes cancer when combined with y,” when the carcenogenicty of y in isolation is well-established. Particularly when those studies flat out say that “a separate review of [x] was not undertaken[.]” 

That is precisely the kind of question Sargon calls on courts to answer as part of their gatekeeping function over experts’ reasoning. Indeed, that question was answered in the negative by the Court of Appeal in Lockheed Litig. Cases, 115 Cal. App. 4th 558, 565 (2004), which was extensively discussed by the Sargon court, which concluded that “[w]e agree with this analysis.”

o

Lockheed Litig. Cases, 115 Cal. App. 4th 558, 565 (2004)

So, third, I disagree that this is really a Kelly question. Kelly asks whether an expert’s theories or methods are “generally accepted” in the relevant field. The flaw of Kelly is that it rejected scientifically sound things for being new, but was perfectly fine with received wisdom, even when the received wisdom was pseudoscientific bullshit. (See, e.g., most criminal forensic techniques of the 20th century.) But the problem with this expert’s testimony is not really that it is new. It is that it is not science. Deciding how to read ambiguities between a series of 10-25 year old monographs is not employing the scientific method. It is just interpreting words.

Which is not to say that Justice Streeter isn’t 100% right that courts should be looking to the “foundational validity” of scientific expert testimony. That should raise the same kind of questions that the U.S. Supreme Court noted in Daubert. Is this actually science? Is the kind of stuff the expert is doing on the stand of the same quality and rigor she would use in the laboratory? Is the conclusion falsifiable?—what could prove the expert wrong? Has anyone done that test outside of litigation? What were the results? Is there a rate of error? But those aren’t questions that Kelly ever demanded an answer to.

Finally, Defendants in these cases might want to reformulate their appellate strategy in the trial court. They are losing on prejudice because they are making unnecessary concessions and because similarly enough un-objected to material is making it into the trial record. 

Plaintiffs in these cases typically don’t appeal trial losses. Which means these important evidentiary issues get decided on appeal only in cases where the procedural posture is particularly unfavorable for the defendant: in appeals of plaintiff jury verdicts. In those cases, appellate courts tend to go out of their way to affirm. (Not because they are necessarily plaintiff-friendly, but because a reversal requires a significant additional expenditure of judicial resources to retry a case.) That being the case, every foregone objection or unnecessary concession compounds the risk of a “no prejudice” affirmance on appeal.

I get that’s not an easy thing to do. Trial lawyers hate making lots of objections because it suggests to the jury that there’s something to hide. And they make concessions to appear reasonable to the court and the jury. But there have to be a huge number of these talc cases pending statewide. Pick a test case. Object to everything. In limine everything. Demand 402 hearings on every expert. Make no concessions. Take one for the record on appeal.

*FWIW, 20 years ago, I was David Faigman’s research assistant while in law school. The experience left me a bit of a Daubert hawk.

Doin' the Right Thing ...

Nocetti v. Whorton, No. C071317 (D3 Mar. 18, 2014)

Plaintiffs failed to show up at trial because their attorney, dying of cancer, apparently miscalendared the trial date. Defendant moved for judgment, and after “reviewing the entire file,” (whatever that means) the trial court entered a defense judgment on the merits. Plaintiffs moved to vacate the judgment under Code of Civil Procedure § 473(b), which affords relief—sometimes mandatory, sometimes at the discretion of the court—from orders that entered due to the mistake, inadvertence, or neglect of a party or its attorney. At a hearing plaintiff’s lawyer was too sick to attend, the trial court denied the motion. The lawyer died soon thereafter, plaintiffs got new counsel, and they appealed. 

In the published part of the opinion, the court holds that plaintiffs weren’t entitled to mandatory relief under § 473(b) because it applies only to “defaults” and “dismissals.” To avoid rendering the discretionary relief as surplusage, established case law reads the mandatory relief narrowly to apply only to default judgments due to failure to respond to a complaint and the plaintiff-side equivalent—dismissals entered after a plaintiff fails to respond to a demurrer or other dismissal-type motion. Because entry of a defense judgment based on a nonappearance after “reviewing the entire file,” is not a dismissal, so defined, plaintiffs don’t get mandatory relief. 

But the court goes on, in an unpublished part of the opinion,* to show plaintiffs a little mercy. It reverses and remands to the trial court to reconsider providing relief under the discretionary provisions of § 473(b), which are not limited to defaults and dismissals, but require any neglect to be excusable. Which having an attorney who appears to have made a mistake while dying of cancer would seem to be.

Reversed.

*I’m on the record as not being a fan of the partial publication rule, which often seems like an excuse to avoid making reasoned decisions about hard or fact-intense issues that bind future cases, when appellate judges think it isn’t worth making precedent. Like decisions about evidence, discovery, and other seemingly mundane procedural issues, for instance. 

But I’ll admit that the rule does occasionally provide a safety valve when what we’ll broadly call “the equities” are offended. In this case, at the § 473(b) motion hearing that plaintiffs’ attorney didn’t attend because he was too busy dying, one of the effectively pro se plaintiffs apparently agreed with the defendant that the court should just “get the matter over with” and he would sue the attorney for malpractice. Some might see that as invited error or waiver. And defendant here made the argument, which the court rejects in a footnote because “[t]his was a voice, though, of frustration, of venting; not a voice knowledgeably inviting error.” Query if that’s a really a call—inferring frustrated sarcasm from a cold transcript—that an appellate court is in a position to make. But it’s the right thing to do. And in the end, I suppose it’s forgivable that this part of the opinion isn’t published, implicit categorical imperative at the heart of the common law appellate process be damned.