One or more of its variants appears in the vast majority of expert reports and transcripts for expert testimony on medical causation:  “reasonable degree of medical/scientific certainty/probability.”  Sometimes, it is attached as a seeming exclamation point at the end of direct testimony of an expert at trial with an exchange like “Were all of your opinions here held to a reasonable degree of medical certainty?” and “Yes, they certainly were.”  What does “reasonable degree of medical certainty” mean? Does it mean something different than “reasonable degree of medical probability”?  If “certainty” means 100% and “probable” means more than 50%, then why are the words “reasonable degree” included in these phrases?  We leave the surveys and exposition of research dating to the 1907 Esso v. Teric case to Bexis and will simply offer that most experts, lawyers, and judges use these phrases reflexively, without pondering their meaning. Clearly, “reasonable degree of medical certainty” plays some role in distinguishing guesswork from something on which a jury can place weight when deciding cases.  These words also come from substantive law and operate independent of the familiar procedural requirements of things like Fed. R. Evid. 401-403 & 701-03 andDaubert.  Independence means that expert opinion on medical causation could pass the “certainty” requirement and still not be sufficiently probative and reliable to be admitted, which happens all the time.  The flip side is rarer, where expert testimony that passesDaubert might still fail because it is not sufficiently certain for state law.  

Rare defines the situation in Valido-Shade v. Wyeth LLC, MDL No. 1203, Civ. No. 12-20003 (E.D. Pa. Nov. 3, 2014), slip op., in a number of respects.  The case is part of the diet drug litigation, which is heading toward its third decade, a rarity among single target litigations.  The injury claimed is pulmonary arterial hypertension, which occurs rarely in the general population--at least actual PAH does.  The particular plaintiff claimed to have been diagnosed with PAH in 2010 after using the drugs in 1996 and 1997.  Although not really explained in the opinion, the reference to “such a long latency period” means that the plaintiff was apparently asymptomatic for the vast majority of the 13 years from last use to diagnosis.  If she had been otherwise, given the ruling in Mingus v. Wyeth, MDL 1203, No. 04-23744, 2006 WL 1050289, *3 (E.D.Pa. Apr. 20 2006), then the plaintiff may have been required to establish her eligibility to sue under a defined exclusion from the Nationwide Class Action Settlement Agreement while her statute of limitations clock ran.  That also would have required her to contend that the drugs she took for “a number of months” produced a disease that was asymptomatic for perhaps a decade by relying on studies that showed a statistically significant increased risk for non-latent disease and no statistically significant risk of latent disease according to the time frames studied.  This same MDL court had previously denied a Daubert challenge to the general causation opinion that the drugs can cause PAH that was asymptomatic for eleven years, In Re: Diet Drugs (Phentermine/ Fenfluramine/Dexfenfluramine) Prods. Liab. Litig, 890 F. Supp. 2d 552 (E.D. Pa. 2012), itself an extension of another court’s denial of a Daubert challenge to general causation opinions for cases with initial symptoms arising more than a year after last use.  Smith v. Wyeth-Ayerst Laboratories Co., 278 F. Supp. 2d 684 (W.D.N.C. 2003).  Given our past involvement with this litigation, these issues, and some of these experts, we are feigning detachment and trying to present it with a modicum of neutrality.  Regardless, this is all quite rare in the world of drug litigation.

In this context, the Valido-Shade court considered a challenge to whether the opinion of plaintiff’s expert, Dr. Lewis Rubin—one of the experts who survived the Daubert challenge in the eleven year case—was sufficiently certain to count as evidence of medical causation under Pennsylvania state law.  Defendants had at their disposal the medical malpractice case Griffin v. University of Pittsburgh Medical Center, 950 A.2d 996 (Pa. Super. Ct. 2008), discussed here, which addressed whether the “magic words” of “reasonable degree of medical certainty” ensured admissibility if the expert’s testimony indicated something far less than certainty.  In Griffin, the plaintiff’s expert opined, purportedly to “a reasonable degree of medical certainty” that the defendant’s allegedly negligent forcible restraint caused her seizure, but the most he could say was that this was “fifty-one to forty-nine percent consideration” and “the least implausible consideration” among the possible causes for the seizure. 

The Superior Court explained that while Dr. Speer had used the “magic words” “reasonable degree of medical certainty,” it is the totality and substance of the opinion that is crucial, not the shibboleths uttered.  The court found his testimony fatally flawed in that he stated that the odds of forcible restrain as the cause of plaintiff’s injury were only 51% versus 49% for the seizure.  In effect, Dr. Speer was employing a “more likely than not” standard.  Griffinruled that such a standard of proof is insufficient under Pennsylvania law for a viable expert opinion.

Slip op. at 6-7 (internal citations omitted).  We quote because we cannot improve on the use of the word “shibboleths.”  Feel free to engage in your own linguistics or exegesis to see why the term is perfect here.  

Like Dr. Speer, Dr. Rubin pegged his level of certainty for diet drugs causing plaintiff to develop significantly latent PAH at 51%, compared to 49% for “an idiopathic cause.”  (Defendants also contended that the plaintiff did not have PAH, but that did not factor into what the court addressed.)  He characterized his own certainty as “beyond a reasonable degree of medical probability” because it was more than 50%.  Because this was the same level of certainty—essentially, a toss-up—that Griffin had rejected, Dr. Rubin’s medical causation opinion simply did not count under Pennsylvania law.  Id. at 7.  Without expert testimony—her other expert merely pulled a “me too” with Dr. Rubin—plaintiff could not avoid summary judgment.  Id. at 7-8.

This is nice result, although one that may not have very broad implications, even under Pennsylvania law.  We have a jaundiced view of such things, but many plaintiffs’ experts with appropriate instruction in the legal standard will take pains to avoid characterizing their level of certainty as merely 51% to 49%.  We have deposed Dr. Rubin, been against him at trial, and filed motions to limit him, so we can say he is more prone than most experts take the position that his view should be accepted by court and jury simply because it is his view.  This same approach is what led him to become the subject of the first decision we know about precluding opinions about a drug or device manufacturer’s motive or intent.  See In Re: Diet Drugs (Phentermine/ Fenfluramine/Dexfenfluramine) Prods. Liab. Litig., MDL No. 1203, 2000 WL 876900, *9 (E.D. Pa. June 20, 2000).  A long line of decisions from drug and device MDLs and elsewhere can be traced to this decision.  So, maybe Valido-Shade will leave a similar legacy too.  We have never claimed any magic applies to our words.