by Nicholas Léger-Riopel*
The emergence of evidence-based medicine (also known as “EBM”), over the course of the last three decades, 1 is attributed to a “synchronisation” 2 of the spheres of medicine and law, aimed at an increased awareness of empirical and objective data in the context of clinical decision making. In law, such a movement translates into an increased volume of statistical and epidemiological studies as admissible evidence before the courts, especially when it concerns medical liability. 3
In the larger context of legal acknowledgement of arguments related to the medical sphere, difficulties inherent in the interface between law and science were revealed as crucial matters for several ruling bodies, since the scope of law goes hand in hand with the coordination of its institutions with medicine’s constant evolution.
The study of health law provides one an ideal observation point from which to view the interactions of medical and legal reasoning. In fact, analysing the conceptual characteristics of evidence-based medicine’s core theoretical aspects might well contribute to a more sophisticated understanding of the movement by the legal system. Such an exercise might reveal, in the end, a more or less comprehensive integration into law of the EBM approach to medicine.
This article aims to foster a better understanding of the consequences of the EBM movement by grasping its implications in relation to evidentiary and substantial legal issues. Namely, we will address the new role of expert evidence in the EBM era, some foreseeable impacts on the well-known standard in civil law traditions of the “reasonable individual”, as well as some impacts of the EBM’s probabilistic turn on the application of factual presumptions regimes. These various objects of inquiry stem from a common thread as they all bear upon the more general question of the interaction between law and medicine in judicial contexts. The very formulation of the legal standard of care, which will be addressed in more details in B.IV., doesn’t remain unchanged from the rise of the EBM perspective in medicine, phenomena which will in turn be briefly delineated in the ensuing remarks.
B. The emergence of evidence-based medicine: a protean reform
Several authors have pointed out that medical knowledge, especially in clinical medicine, generally builds upon itself in an idiosyncratic manner. 4 In other words, clinical decision making involves the mobilisation of several different types of knowledge, acquired either through the physician’s academic endeavours or through practice and experience, in a context where available epidemiological data are not integrated in a way that would make them considered an important and reliable source of information for clinical decision making. 5
Noah reminds us that the EBM movement is the result of the reform of a practice of medicine traditionally “based on opinions”, which resulted in what has been described as a some-
* The author is an attorney and a Ph.D. candidate in law at the University of Montréal, Canada.
1 The paternity of the expression “evidence-based medicine” is generally attributed to David Sackett, a Canadian physician, as well as to his colleagues from McMaster University in Ontario, who have developed such a concept as a way to teach and practice medicine, mostly in parallel with the activities of the “Evidence-Based Medicine Working Group”. Please also see: Glancy/Saini, J. Am. Acad. Psychiatry Law 2009, p. 439.
2 Glancy/Saini, J. Am. Acad. Psychiatry Law 2009, p. 438; Noah, Ariz. L. Rev. vol. 44, 2002, p. 373; Farell, Cardozo L. Rev. vol. 15, 1994, p. 2183; Mello, Wake Forest L. Rev. vol. 37, 2002, p. 821.
3 Mello, Wake Forest L. Rev. vol. 37, 2002, p. 821. Christoffel/Teret, Am. J. Pub. Health vol. 81 1991, p. 1661; Lempert, Colum. L. Rev. vol. 85, p. 1985, Gronhovd, Notre Dame L. Rev. vol. 62, 1987, p. 688.
4 Several authors maintain that traditional medical reasoning is but an interpretative procedure through which the physician’s anecdotal, experimental and scientific knowledge comes together during the “particularization” phase required by any clinical case. Tenenbaum, Journal of Health Politics. Policy and Law Vol. 19 No.1, 1994, p. 27. McDonald, Ann Intern Med. vol. 124, 1996, 56-62.
5 Michel, Polski Prezglad Chirurgiczny, vol. 79 no. 2, 2007, p. 150; Saarni/Gylling, J. Am. Acad. Psychiatry Law Vol. 37 no. 4, 2009, p. 438; Sackett/Rosenberg/Gray, et al., BMJ vol. 312, 1996, p. 71.
what unreflective adherence to well-entrenched habits in clinical decision-making, furthermore generally refractory to the latest findings of medical literature and biomedical research.6
Evidence-based medicine, while it addresses these shortcomings of clinical practice, exhibits an explicit normative dimension, as it tells physicians making decisions to give priority to the most significant bio-statistical information available, which is often compiled in clinical guidelines provided to clinicians.7 In so doing, a reorganization is suggested when it comes to the hierarchy of sources taken into account throughout the physician’s decision-making process, leaning toward a prioritization of large-scale and statistically significant epidemiological studies — specifically those whose methodology complies with the standard known as “double blind, random clinical studies.”8
Thus, the EBM approach relies on the conviction that it is possible to establish a hierarchy of useful medical sources with the perspective of reducing biases.9 Such an approach embodies a philosophy which authors have acknowledged as a prioritization of reasoning more receptive to the so-called large numbers provided by epidemiology than to the “case-by-case” method favoured by pathophysiology and clinical experience.
EBM may be perceived as the result of several types of pressure and of the confrontation of contradictory conceptions of medical science. Whether it be pressure applied on our health systems (in favour of a greater rationalization or efficiency) or increasing demands for information technologies within clinics and hospitals, the structure of the patient/physician relationship is undergoing significant changes in the name of evidence-based medicine.10
According to several authors, the EBM philosophy reorganizes the balance of power at the centre of the medical community by suggesting a conception of medicine based, for the most part, on the ideals of efficiency generally sought by health system administrators and managers.11 Others see it as a resurgence of scientific positivism12 or of some form of latent “scientism.”13
Noah points out that evidence-based medicine deals primarily with the procedural aspects of clinical decision-making, not by promoting any particular form of intervention but rather by taking into account, at the first opportunity, a specific kind of study deemed more “scientifically viable” than the traditional habitus of clinicians, based on experience and practices generally recognized by their peers:
By constructing a rough hierarchy that reflects the value of the different types of clinically-relevant information, evidence-based medicine attempts to improve decision-making by practicing physicians. When faced with a clinical problem, health care professionals should, in descending order of preference, look for guidance in systematic reviews of randomized controlled trials, the results of individual controlled clinical trials, observational (uncontrolled) studies, and anecdotal reports of clinical observations. The sections that follow elaborate on each of these different types of biomedical information. Personal clinical experience remains an essential predicate for the effective application of EBM, but it should not provide the primary basis for making treatment decisions.14
Several authors have also suggested that while the EBM movement advocates a rational hierarchy of the numerous resources available to physicians, various phases of the clinician’s decision-making process remain largely dependent upon his or her practical abilities — including the accurate identification of a source or the recording of observations required by a diagnosis.15
EBM’s methodology rests on two basic premises: (1) it is possible for a physician to identify the most helpful source, given the specific case at hand, and (2) relevant facts are non-ambiguous and accessible through common clinical observation.16 Given these postulates, some authors have spoken in favour of an expansion of EBM’s current analytical framework, namely through due consideration of so-called “implied” clinical knowledge17 and the acknowledgement of the contribution of social and contextual factors to the definition of “pathology”.18
Hence, evidence-based medicine prompts the physician to heightened reflexivity when it comes to the sources he or she refers to in daily clinical practice,19 for instance, by introducing complexity into common medical knowledge through the notions of “fallibility” and “falsifiability” — which, to some observers, represent the most prevalent characteristics of the new approach.20 This added complexity, as will be shown in the next sections, brings to light the different or diverging ways law and medicine grasp scientific uncertainty.
C. Legal acknowledgement of evidence-based medicine
I. Legal evidence vs. scientific evidence: different ways to address uncertainty
Anyone remotely interested in health law will readily testify to the recurrent and inherently enduring character of the difficulties encountered at the level of judicial recognition of arguments related to medical science.
Law — driven as it is by a decision-making dynamic — maintains with uncertainty a relationship that is quite different from science’s,21 in particular since the judicial process has as its primary objective the stabilization of legal interactions through specific rules of law such as stare decisis, prescription and the principle of irreversibility of court decisions — which all aim at containing the uncertainties associated with litigation.
6 Noah, (note 2), p. 382. Please also see: Berwick, Qual. Saf. Health Care, vol. 14, 2005, p. 315.
7 Davidoff/Haynes/Sackett/Smith, British Medical Journal vol. 310, 1995, p. 1085. Please also see Tingle/Foster, ed., Clinical Guidelines: Law, Policy and Practice, 2002, p. 45.
8 On the history of this standard, a contributing factor to the acknowledgement of the “scientific” status of medicine, please see: White/Hillis, Health Sociology Review Vol 11 (1 & 2), 2002, p. 5. Please also see: Stolberg et al., AJR Vol. 183, 2004, p. 1539.
9 Ashcroft, Med Ethics vol. 30, 2004, p. 131.
10 Baudouin, Les Cahiers de droit, vol. 28, no. 1, 1987, p. 117-124.
11 For a detailed study of this topic, please see: Rosoff, Journal of Health Politics, Policy and Law Vol. 26 No.2, 2001, p. 328. Please also see: Belkin, Journal of Health Politics, Policy and Law vol. 22, 1997, p. 509.
12 White/Hillis, (note 8), p.5.
13 Mercer, Social Epistemology: A Journal of Knowledge, Culture and Policy vol. 22, no. 4, 2008, p. 405.
14 Noah, (note 2), p. 381.
15 Henry et al., Academic Medicine Vol. 82, no. 3, 2007, p. 293.
16 Id, p. 292.
18 White/Hillis, (note 2), p. 9.
19 Noah, (note 2) p. 465.
20 Parker, Medical Humanities vol. 31, 2005, p. 23, notably at p. 28.
21 Leiter, BYU L. Rev., 1997, p. 803.
The analytical framework we propose defines the epistemological properties of several concepts which are bound to meet and interact as scientific rationality makes its way into our courts, especially in the context of medical liability. Two categories of evidence are thus introduced, each bringing its own contextual and historical particularities and driven by its own functions and principles.
As pointed out by Leiter in a remarkably thorough study of the question, evidence in law and in science evolves in different matrixes where various sets of objectives must be distinguished, first according to their internal workings as practical ways to organize knowledge (epistemic functions), and, second, because our legal system proves to be more and more open to considerations which go beyond a mere amalgamation of logically-connected standards (non-epistemic functions).22
First and foremost, legal evidence owes its specificity to the particular functions of judicial decisions, which, unlike scientific discoveries, do not represent actual, real events. To believe otherwise would be to greatly misconstrue the normative and performative23 dimensions law shares with reality. As underlined by Flückiger, the question has troubled many a great legal scholar as it would be idle to recognize in a judgment the same value as scientific truth, as a judgment aims to provide with what is right, in accordance with current texts, and is not bound by strictly scientific imperatives and methodology:
It then becomes futile, according to Van de Kerchove, “to remind ourselves of the fiction of absolute scientific truth, inherent to judicial decisions, in order to acknowledge the fact that the judgments on which they rely benefit from an irrefutable presumption of truth, and that they also benefit from an authority that, within the limits of the law, is deemed irrevocable.” Bruno Latour, in an ethnographical comparison between jurists and scientists, (…) concludes that it becomes imperative not to ask sciences to decide, not to ask law to speak the truth. (TRANSLATED BY THE AUTHOR) (references omitted)24
Another factor which greatly differentiates scientific evidence from legal evidence is that law, as a particular expression of a democracy, sees its “truth-finding” potential limited by the nature and requirements of its own institutions.25 A specific piece of evidence might not be relevant, while a piece of relevant evidence might not be admissible, given due consideration to constitutional imperatives. Such limitations might substantially reduce the volume and scope of data available to magistrates, and can only be justified by the functions of law (which we have qualified as non-epistemic), around which multiple values and objectives circulate:
Furthermore, law establishes limits whose objectives reach beyond a manifestation of the truth. All evidence is not necessarily admissible, since all means to obtain it are not necessarily valid. Discovery of the truth is not the sole objective of a trial, and it must certainly not become so. As Perelman reminds us: ‘techniques related to evidence and the truth it must bring forth […must] reconcile with other values, sometimes viewed as more important.’26
Science, as a dominant paradigm of the truth in law, proves quite useful in establishing relevant facts in a judicial con- text.27 Since the primary objective of evidence management is to convince the magistrate of the existence of a given fact, one can identify a similarity between law and science: both aim to find the truth. In the context of a trial, however, such a movement might have to adjust to the requirements of other values sought by the law construed as a system open to society as a whole.28 As will be discussed in the following section, the encounter of scientific and legal knowledge in judicial contexts often reflects on the administration of expert evidence.
II. Management of expert evidence in the context of evidence-based medicine
Early on, the EBM philosophy focused its attention on the conceptual framework surrounding “expertise” as part of the hierarchy of sources presented to clinicians. A few of its strongest advocates pointed out that the movement should encourage a better allocation of resources by avoiding (as much as possible) the resort to an expert, whose role can often enough be thought of as reduced to a mere “means” of introducing a specific piece of evidence, namely statistical and epidemiological data.29
Others have attributed a transitional role to the knowledge and experience of clinical experts specialized in given fields, as long as empirical data complying with the requirements of EBM were made available.30 Hence, and as far as expert evidence is concerned, EBM’s position respects the hierarchy of medical resources it proposes, while favouring the epidemiological perspective over decision-making procedures centered on the clinician’s personal experience.31
23 Meaning that a legal decision sometimes creates a statement of fact that did not exist prior to it. For instance, let’s consider the “I now pronounce you man and wife” of the public official invested with the authority to perform a marriage, or, obviously, the content of a court’s decision. I wish to thank Professor Jean-François Gaudreault-Desbiens, who pointed out that the “heart” of a judgment’s performative function might very well be limited to its conclusions. On the question of performative statements in law, please see: Austin, How to Do Things with Words, 1962.
24 Flückiger, Revue européenne des sciences sociales Tome XLI, no. 128, 2003, p. 108.
25 Keeping in mind that the institutional characteristics of each level of decision-makers (such as prevalent judicial policies), might come into play: Zaor/Léger-Riopel, Droit professionnel et disciplinaire vol. 351, 2012, p. 285. Molot, McGill L. J., 1972, p. 310. Comtois, R. du B., 1999, p. 121-154.
26 Comtois, R. du B., 1999, p. 121-154.
27 Farell, (note 2) p. 2183: “S]cience has the strongest claim to truth, because unlike other disciplines, scientific truths are based on rigorous, replicable, empirical experiments and observations of a real world that can be known through the senses. It follows then that law, as a system for resolving disputes based on truth and justice, should make use of scientific facts to the greatest extent possible. While the law may be seen as a different enterprise, it nevertheless must strive to include scientific explanations in its truth.” (p. 2191).
28 Houin, Revue internationale de droit compare vol. 5 no.1, 1953, p. 69.
29 Mello, (note 2), p. 852. On this matter, the author refers also to Shuman, J. Health Pol. Pol’y & L. vol. 26, 2001, p. 280-281.
30 Meaning that the EBM movement criticizes, first and foremost the “experimental” aspect of expertise. Tonnelli, Academic Medicine Vol. 74, no. 11, 1999, p. 1187.
31 Mello listed two categories of arguments favouring an elimination of clinical expertise as a unique or primary source of evidence in health law. Those two categories are directly connected to multiple biases sufficiently prevalent to influence expert evidence. Mello, (note 2), p. 823.
While several judicial decisions have addressed the sensitive task of supervising the activities of expert witnesses, the most famous of them all remains the Daubert32 case, which requires that any expert evidence be derived from a methodology offering enough “testability” as well as an already-disclosed threshold of error, be published and already reviewed by peers, and be generally accepted as valid by the targeted scientific community.
When it comes to the role and assessment of expert evidence, the relationship between medicine and law offers each an opportunity to appreciate the epistemic proximity of the disciplines. On that subject, Mercer points out that the reorganization he has witnessed in several regimes of scientific and expert evidence management were prompted by a proliferation of critiques related to the interactions between law and science33 — whether respecting the tendency of experts to deform scientific truth or the obstacles awaiting judges who must appreciate the quality and weight of scientific evidence:
Like the EBM “revolution,” the Daubert revolution hooked into broader critical debates about problems with law and science, but ultimately focused on “experts” as the problem and “science” as the solution. In a sense both movements can be seen as offering “epistemological fixes” (appeals to ideals of scientific method and mechanical objectivity) to perceptions of broader socio-technical problems surrounding medicine and the interactions of law and science. As might be expected the neatness of the rhetoric of such “epistemological fixes” would be difficult to sustain, as the movements became influential and actual practices and doctrines began to be re-shaped.”34
Although it was released in an American context, the Daubert case has found its way into Canadian law and has since been quoted twice by the Supreme Court.35 In fact, Daubert bears witness to an adjustment of the law to new and modern forms of medical science, which expose tensions between a standard of medical fault traditionally based on the actions of peers and a somewhat more coherent standard driven by the precepts of evidence-based medicine.36
Farell has observed that the reasoning adopted in the Daubert case leans toward a system of admissibility of scientific evidence more or less in tune with the inherent normativity of evidence-based medicine,37 as it seems consistent with the empirical requirements of the movement. In that context, critiques often addressed to EBM might as well be directed to the evidence regimes inspired by the Daubert case: epidemiological data tend to be given unwarranted credibility when they are weighed by a magistrate who is not sufficiently versed in current statistics,38 while they tend to overshadow the existence of alternate approaches to clinical practice, in particular the physio-pathological parameter.39
Hence, a noticeable shift might occur at the level of the proverbial “duel of experts,” the debate centring no longer around the questions of credentials and opinions of experts, but rather focusing on the sources they relied upon at the time of jotting down their respective conclusions (the whole subject, of course, to their validity and credibility, as defined by evidence-based medicine40).
That being said, legal acknowledgement of evidence-based medicine, as a unit of measure of the scientific value of a piece of evidence in the context of medical liability, might very well misconstrue the epistemological and institutional limits imposed on magistrates, as well as the difficulties they must face when addressing complex scientific matters.41
What grants the regime its permanence (through its capacity to adapt to ever-changing social and scientific realities) is undoubtedly the characteristic flexibility of medical liability’s regime. Those attributes of medical liability have been acknowledged by Cohen as opposed to the “hardening” which would occur as a result of a direct integration, in law, of the values and scientific premises of evidence-based medicine.42
The intersection of law and medicine at the level of expert evidence raises general questions such as the role of customs and habits in delineating a standard for medical fault and the impact of EBM-based clinical guidelines on the emergence of modern ways of perceiving and practicing medicine. The extent to which evidence-based medicine is recognized before courts of law will undoubtedly impact what is legally conceived as an acceptable practice, as the legal standard of the “reasonable” physician is pervious to developments in medical knowledge and clinical practice.
III. Medical liability and its core institutions: the notion of “a reasonable physician”
Several authors have pointed out that the notion of “a reasonable individual,” as found in the laws of various states, is rather imprecise and, as such, often referred to as “vague.” The epistemology of law could explore the objectives of that “out-of-focus” status of such a central standard for liability, which is invoked in general civil liability as well as in professional and medical liability.43
32 Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993). In that case, the United States Supreme Court developed a four-step set of criteria according to which a magistrate is asked to rule upon the quality of scientific evidence. Please also see: Harv. L. Rev., vol 113, 1999, p. 1471, n. 26. “The four Daubertfactors are:(1) whether the methodology upon which the testimony is based has been, or can be, tested; (2) whether the methodology „has been subjected to peer review and publication;“ (3) the methodology’s „known or potential rate of error“ and the availability and use of standards to control the methodology’s operation; and (4) the extent to which the methodology is generally accepted in the relevant scientific community.”
33 Mercer, (note 14), p. 408.
34 Id., p. 409.
35 R. c. J.-L.J., 2000 CSC 51; R. c. Trochym, 2007 CSC 6. The Daubert case was also referred to in Quebec by decision-making authorities dealing with administrative and criminal law: CSSS de Port-Cartier, 2011 QCCLP 2344; R. c. Croteau, 2004 CanLII 26808 (QC CS).
36 Hurwitz, BMJ vol. 329, 2004, p. 1024.
37 Farell, (note 2).
38 Mello, (note 2), p. 856, n.120.
39 The expression “Exclusionary Ethos” was coined by Mercer in order to suggest the tendency of the Daubert case to exclude emerging clinical practices. Edmond/Mercer, Law and Policy vol. 26, 2004, p. 231. On the matter of excluding complementary or alternative medical practices, especially when they rely on qualitative studies, please see: Hunter/Grant, Evidence-Based Integrative Medicine vol. 2, no. 4, 2005, p. 189-194.
40 Mello, (note 2), p. 854.
41 The stakes seemed obvious to Justice Rehnquist, in the Daubert case, 509 U.S., p. 600 “I am at a loss to know what is meant when it is said that the scientific status of a theory depends on its ‚falsifiability,‘ and I suspect some of [my fellow federal judges] will be, too.“ Please also see: Farell, (note 2).
42 Cohen, Seton Hall. L. Rev. Vol. 33, 2002-2003, p. 943.
43 As underlined by Professor Patrice Deslauriers: “In this respect, it is useful to point out that like in the common law of civil liability, a physician will not be judged on the merit of his own ordinary behaviour. In other words, the task is not to prove that he has disobeyed his standards. Contrary to this method of analysis, the objective is to determine if the author of the damage has acted in compliance with the “reasonably prudent, cautious and competent physician standard.” On the notion itself, please see: Deslauriers, Responsabilité, vol. 4, Titre II, Édition Yvon Blais, p. 127.
Following the same reasoning, Louise Langevin, in a remarkably astute study on the notion of “a reasonable individual” in Quebec law, suggested that it is, in fact, the imprecise character44 of the standard which (by maintaining enough flexibility to adjust to an eventual evolution of the context) allows the liability system as a whole to satisfy the ends traditionally sought by law:
This capacity to adapt to times and circumstances endows this model with an appearance of equity. In fact, while it calls upon a somewhat abstract model, it is not totally blind — it offers our courts enough flexibility to render decisions that offer clear indications that justice was rendered. Courts and authors then agree on an abstract model of determination, which still takes into account all relevant external circumstances.45 (TRANSLATED BY THE AUTHOR)
Such remarks rely on a conception of law which takes into account that the institution of liability is not a formal network of rights and obligations where a mere exercise in deduction allows for a perfect match of the legal norm to the relevant facts of a case. It is only by “opening” law to means sought after outside the legal norm that one can effectively eliminate the notion of a legal system viewed as a purely algorithmic formula. In fact, such an “open system” view of the law was favoured by the legislator at the time the Civil Code of Quebec was promulgated.46
As already mentioned, Leiter sees flexibility as a means to demonstrate that the liability system and its numerous rules rest upon a dual structure comprised of epistemic and non-epistemic perspectives. In other words, law usually tends to remain flexible enough to allow for the search for practical objectives, or for the implementation of external goals while remaining true to its formal standards.47
Thus, it is legal activity’s diversified attributes, as well as its finalities irreducible to the mere production of “viable” or “valid” knowledge, that clearly differentiate it from science. Knowledge attributable to scientific activities is not, generally speaking, confronted with the numerous listeners, interests and objectives a judicial decision must satisfy.
IV. The regime of factual presumptions: between causality and probability
As we have seen, medicine and law approach uncertainty in different ways — which is of acute interest when the courts are expected to determine the cause of an iatrogenic incident not through direct causation, but rather by applying factual presumptions, known in various jurisdictions under the doctrine of res ipas loquitur.48 The question of factual presumptions is not merely procedural as it may acquire unsuspected weight in the substantial issues of allotting liability in contexts of scientific uncertainty or of conflicting expert evidence. That is, the identification that damage occurred outside the normal course of events may very well in turn underpin what will be deemed as a reasonable clinical practice by the decision-maker.
According to Jutras, problems in the application of factual presumptions may stem from the diverging worldviews of medicine and law about what a normal course of events is in a clinical context. While certain therapies come with the knowledge of a more or less important degree of risk, judges may show a tendency to conclude to negligence when the risk of the therapy was low. In doing so, courts are transforming the presumption of facts to a presumption of negligence, therefore “denying that the therapy itself came with inherent risks which have nothing to do with negligence.”49 For Jutras, a keener understanding of the factual presumptions regimes might be beneficial to shed some light on the medical liability “crisis”:
But there is more: the structure of factual presumptions, in itself, is inconsistent with the genesis of some iatrogenic incidents. Indeed, referring to a factual presumption implies the occurrence of an event perceived as abnormal. Yet, several therapies come with some inherent degree of risk, meaning that negative consequences remain possible, and so, normal. If the chances that such a tragic consequence might occur are high, we can hardly speak of an “abnormal event” when tragedy strikes.(…)
Civil liability’s conceptual structure is thus in a situation of crisis, mostly because of this lack of harmony between legal and medical reasoning, as well as a potential reorientation of fundamental principles aimed at facilitating the compensation of victims. (TRANSLATED BY THE AUTHOR) 50
Hence, we must conclude that factual presumptions refer to a notion of judicial causality which is quite different from medical causality. In fact, maybe such a difference in the epistemic properties of the notion of “causality,” as it manifests itself in law and in science, can explain why the implementation of factual presumptions is often laced with difficulty. As Mello points out, as clinical reasoning assesses multifactorial causation, the judicial activity is bound to abide by a binary reasoning as its outcome – the judgment – is in itself binary by nature.51
Keeping these issues in mind, the convergence of EBM’s probabilistic (or statistical) approach and of the regime of presumptions might give rise to certain contradictions. As pointed out by Neil B. Cohen, the “weight of evidence” referred to in civil matters is often perceived as being based on an analytical framework where the onus can be defined in probabilistic terms (namely, 50% +1). Such an abstract view suggests a context where the notions of legal evidence and of medical evidence might be confused: if preponderance or probabilities requires a ratio of 50% + 1, a hypothesis whose margin of error reaches 5%, meaning it is 95% reliable, can appear more than sufficient.52
When it comes to factual presumption, associating statistics with legal evidence might reduce the possibilities of acquittal based on the occurrence of another, less probable cause. In the end, maybe this convergence of legal evidence and of EBM-type evidence demonstrates a gradual transformation of
44 In this context, the notion of “imprecision” could be envisioned as a form of “sub-determination,” as suggested by Timsit, Les noms de la loi, 1991.
45 Langevin, Les Cahiers de Droit vol. 46, no. 1-2, 2005, p. 359.
46 If the Civil Code remains somewhat vague on the subject of specific norms or notions, it expresses, to a certain extent, the numerous interests and ambivalences of our society. We must see these rules as the pores through which the Code is allowed to breathe, gain strength and adapt through the interpretation that will be made of it as our society evolves” Ministry of Justice, Commentaires du ministre de la Justice: le Code civil du Québec, t. 1, Québec, Les Publications du Québec, 1993, p. vii. (translated by the author).
47 Leiter, (note 21), p. 816.
48 On the subject of presumptions used in Quebec’s law on medical liability, please see: Deslauriers, (note 43), notably, the author also quotes Nicol, R.D.U.S., vol. 27, 1996-1997, p. 139.
49 Jutras, Les Cahiers de Droit vol. 31, 1990, p. 835.
51Mello, (note 2), p. 829.
52 Id, p. 837.
the obligation of means (generally attributed to a physician) to an obligation of results.53
Since any abstraction brings a certain degree of simplification, this perspective overshadows the complexity of the rationalities at play by removing from the analytical framework the significant differences between scientific and legal evidence. On this subject, Ménard reminds us that the unconditional acceptance of the statistical views in a judicial context might very well reduce the scope of the evidence traditionally offered to magistrates: causality in law is allotted in regard to the whole of the proof available, which may include statistics without requiring it:
The expert will say that all we can be sure of is that this or that complication arises in 60% of cases, without addressing the question of whether or not it probably occurred in the case at hand. He or she won’t go further than inferring the fact. (…)Statistical evidence might be useful at a quantitative level, but it shall in no way be decisive. Furthermore, when statistical evidence does not establish causality according to the preponderance of probabilities, causality in law might still be obtained if the evidence as a whole warrants such a conclusion.
Reducing the whole debate on causality to a mere question of statistical causality might lead the courts to an overly rigid interpretation of causality…54(TRANSLATED BY THE AUTHOR)
Seen as evidence, the probabilistic approach receives some interesting consideration in the theoretical framework developed by the author Banakas, according to whom there exists a “natural” or “scientific” cause, generally associated with liability without being always identical to “judicial” cause — the only one actually sanctioned by law.55 From this theoretical perspective, the EBM movement offers what a Scottish Supreme Court Justice has called a “naked statistical witness”56 — meaning that statistical evidence will have to be corroborated by some sort of supporting evidence which will apply the statistical data to the particular case at hand.57
The institutions of medical liability seek the epistemic properties of the notions of causality in law and in science, quite different from one sphere to the other, and these properties, in turn, allow us to perceive with clarity the fact that probably causality will never conform entirely to the requirements of science. Civil liability, as a system “open” to external dialogues, refers to flexible notions that adapt to the relevant epistemic requirements.58 In the end, the notion of causality in law might very well be revealed as a “technique of imputation,” invoked by the decision maker and guided by the need for scientific validity (without being categorically reduced to such a technique). In any event, what is of considerable interest to the health law scholar is the normative dimension of EBM towards a greater use of statistics in medical liability contexts, which may result in a distanciation from a standard of care based on what is common practice in the medical community.
D. Reorienting a standard traditionally based on the approval of peers
From another standpoint, the EBM movement can be seen as advocating a safe distance from the traditional decision-making habits of clinicians, while focusing on the hierarchy of scientific resources to which they defer.
Such a rationalization of medical sources, often presented as an equivalent (if not a synonym) of “good clinical practices,” does not always go hand in hand with the norm of medical liability, developed by the courts and based on the “reasonable” criteria of a given practice.59
Traditionally, the legal formulation of the standard of “medical fault” has emerged in parallel with the attribution of a particular status to the medical profession, based on a principle known as “justice by one’s peers”. Carter has identified the conceptual and socio-historical precepts of such a particular approach purporting to the notion of medical fault, while underlining the various sources of the deference of decision-making authorities to the standards and customs specific to the medical community:
Scholars identify several theories to explain this special treatment of the medical community. One of the most frequently cited explanations for judicial deference to medical custom is respect for medical professionals. Another justification is ‘the inability of laymen to evaluate the technical judgments of specialists.‘ One commentator explains, ‘Courts have recognized the fact that laymen lack the capacity to adequately evaluate a physician’s conduct or to adequately determine what a reasonable and prudent man under the same circumstances with specialized training and knowledge would have done.’ (…) Thus, a plaintiff rarely can recover when the defendant physician complied with the customary standard of care.60
Several authors have found in the emergence of the EBM movement warning signs of a likely reorganization of the standard of medical fault, traditionally based on the recognition of proverbial “rules of the trade” and of customs cherished by the medical community. As a result, analytical frameworks might be transformed as a noticeable shift occurs from what is usually done in medicine to what should have been done in a given case.
Although a relatively small number of decisions from Canada’s and Quebec’s courts deal specifically with evidence-based medicine at the moment, one should refrain from concluding (quite prematurely) that the movement is not widely accepted in law. As long as it is viewed as a “paradigm” of medicine, it is possible for EBM to play an active part in the
53 Baudouin, (note 10). Jutras, (note 49), p. 827.
54 Ménard, Les Développements récents en droit de la santé, Barreau du Québec, 1991, p. 1. Please also see the reasoning followed in R.C. c. Régie de l’assurance-maladie du Québec, 2004 CanLII 64163 (TAQ).
55 On the matter of causality as a question of judicial policy, please see Banakas, Revue Lamy Droit Civil no. 40, 2007, p. 93-99.
56 McTear v.Imperial Tobacco Ltd,  Scots CSOH 69 (J. Nimmo-Smitt). Rosoff points out that, traditionally speaking, judges are less inclined to accept qualitative evidence: Moreover, law is much more a qualitative (verbal) than a quantitative discipline; judges might be less comfortable relying, or instructing a jury to rely, on a guideline derived from quantitative, statistical processes rather than on expert witnesses’ “interpretive stories.” Rosoff, (note 11), p. 352.
57 Mello reveals that scientific causality does not usually require the “particularization” exercise deferred to in civil trials. As such, she highlights the limitations of both correlation and causality. Mello, (note 2).
58 According to Kouri, the difficulties encountered while managing scientific evidence during trials call for the immediate adaptation of “equitable solutions” to the judicial framework. Kouri, R.D.U.S. vol. 32, 2001, p. 213.
59 See note 45 and Noah, (note 2), p. 382.
60 Williams, (note 44), p. 501.
construction of a “normal science of medicine.”61 As such, the acknowledgement of the legal status of clinical guidelines (as a means of propelling and implementing the objectives of the EBM movement) might give birth to a corpus of judicial debates involving various conceptions of medicine.62
E. Closing remarks
Judicial acknowledgement of the premises of evidence-based medicine might depend on various considerations related to the medical and professional liability’s conceptual structure, as well as on the institutional characteristics of the decision-making organs dealing with clinical liability.
The particular (and rather complex) interactions of law and medicine might reveal some tensions between the normative orders in the midst of which different (and sometimes conflicting) conceptual frameworks coexist. The significance of customs and habits throughout the medical community (when it comes to determining the “reasonable” aspect of a given clinical practice), not unlike the acceptance of emerging practices and experimental therapeutic techniques, might vary according to different (and, once again, conflicting) conceptions of medicine, and to the degree of acknowledgement of EBM as a paradigm of “good practices.”
In retrospect, one must observe that law, as a knowledge-producing process, adopts a shifting position vis-à-vis the data available in medical science. Thanks to some degree of irregular proximity, the similarities between the disciplines – as clearly revealed through the activities of courts — call for a reorientation of the analytical framework toward an approach which will be able to grasp to a greater extent the complexity and reciprocity of the relationships between law and medicine.63
61 The normativity of the EBM movement can be implicitly accepted in law — particularly within the “framework” in which medical liability issues are considered. One can imagine that in some specific decisions, while evidence-based medicine is not referred to directly, parties and decision-makers assess the quality of allegations and of evidence according to a “hierarchy of EBM sources.” Such reasoning might be attributed to (and flow naturally from) the Collège des médecins du Québec c. Fanous, 2009 CanLII 31615 (QC CDCM) (on appeal before the Tribunal des Professions).
62 On this matter, please see: Cheah, Ann Acad Med Singapore vol. 27, 1998, p. 533; Léger-Riopel, R. du B. Can. vol. 90, no. 2, 2012, p. 303.
63 On the question of medicine and law both defining notions used in the area of health law, please see: Noah, 50 Hastings L.J. vol. 241, 1999, p. 293.