The case for across-the-board application of the loss-of-chance doctrine.

• Author: Kieffer, Jonathan P.

It makes jurisprudential and public policy sense for the doctrine to apply to better-than-even chance cases when plaintiffs cannot prove causation

NEGLIGENCE law traditionally has required that findings of liability be predicated on a showing that defendants were the cause in fact of plaintiffs' harm. To prevail, plaintiffs had to show that "but for" defendants' negligence, the injury complained of would not have occurred.

In certain sub-sets of negligence law, application of the traditional rule had harsh consequences. Particularly in medical malpractice cases in which a physician's failure to diagnose a patient's pre-existing disease or condition allowed that disease or condition to progress, plaintiffs were barred from recovery in cases where their chance of a better outcome, absent negligence, was less than 51 percent. Recovery was denied because they were unable to prove that their injuries would not have taken place if proper diagnosis and treatment had been provided.

In response to the perceived inequity of denying recovery in these cases, courts during the last 20 years have developed what has come to be known as the loss-of-chance doctrine. The specific nature of the doctrine varies by jurisdiction. Some courts relax causation requirements simply by accepting a lower threshold of proof.(1) Others view the lost chance itself, rather than the ultimate outcome, as the compensable injury.(2) Still others appear to recognize a hybrid of the first two approaches.(3)

In general, the doctrine has been successful in facilitating compensation for injured plaintiffs, and it now is the majority rule.(4) As currently applied in almost all jurisdictions, however, the loss-of-chance doctrine results in significant inequities for defendants. Virtually all courts that recognize the loss-of-chance doctrine apply it only in those situations where the patient had less than a 50 percent chance of recovery or survival absent negligence (known as "not-better-than-even" cases), refusing to extend the doctrine to cases where the lost chance exceeded 50 percent (known as "better-than-even" cases). As a result, a plaintiff with a 51 percent chance of recovery or survival who is able to establish negligence by a preponderance of the evidence is allowed to recover full damages for the ultimate injury suffered, notwithstanding the fact that there is a 49 percent chance that the injury would have occurred even if a proper diagnosis had been rendered and appropriate care given.

In short, the equities have never been in balance in this area of tort law. Prior to the development of the loss-of-chance doctrine, large numbers of deserving plaintiffs failed because of their inability to make out a prima facie case of negligence, resulting in a windfall for culpable defendants. Today, the pendulum of compensation has traveled to the opposite end of the spectrum, and defendants are routinely held liable in damages for injuries that they did not cause, resulting in the systematic overcompensation of plaintiffs.

It is strange that this problem has received virtually no attention in the courts or from commentators.(5) This fact is doubly surprising, given that a broader application of the loss-of-chance doctrine would allow defendants to limit damages to those actually flowing from their negligence, while at the same time allowing courts to reach results that intellectually are more credible.

In refusing to extend the loss-of-chance theory to all cases in which plaintiffs cannot establish causation under traditional principles, courts confuse the probabilities associated with claimants' health and survival with the preponderance of the evidence standard, ignore the common law and academic context within which the theory originally developed, and achieve results that are at cross-purposes with current judicial and legislative efforts to curb the perceived excesses of the tort system, particularly as related to medical malpractice litigation.

NATURE OF THE PROBLEM

1. "What" and "How"

   A significant number of loss-of-chance cases involve alleged acts of medical negligence--often omissions--that combine with a patient's pre-existing disease or condition to produce injury or death. Because of this and because both the patient's chances of a better outcome and the evidence establishing negligence often are expressed in percentage terms, courts frequently confuse the probabilities associated with plaintiffs' health and survival with the preponderance of the evidence standard.(6) As one commentator has observed, courts fail "to distinguish between what is to be proved and how it is to be proved."(7)

   The "what" that must be proven focuses on damages--namely, that the negligence alleged deprived the patient of a chance of recovery or survival, with that chance expressed almost invariably in percentage terms. The "how" centers on the preponderance of the evidence standard that at least 51 percent of the evidence produced must persuade the fact finder that the defendant caused the harm.

   The result of confusing these two variables is that courts typically conclude that if the patient had a better-than-even chance of recovery absent negligence, and if negligence is established by a preponderance of the evidence, then the physician was the cause in fact of the patient's entire injury and is liable for all associated damages.

   This conclusion is analytically incorrect, in large part because a traditional negligence case does not involve a pre-existing condition, and therefore the agent or instrumentality of injury or death is not in question. The single uncertainty is whether that agent or instrumentality worked harm on the plaintiff because of the defendant's negligence.

   In contrast, a loss-of-chance action by definition involves multiple uncertainties, and the fact that negligence is proved by a preponderance of the evidence is not the equivalent of proving that the negligence was the cause of the patient's ultimate harm. In an absolute sense, causation for a patient's ultimate injury in a loss-of-chance case can be established only by considering the mathematical product of the evidence establishing negligence, together with the patient's original chance for a better outcome.

   Because most courts do not apply the loss-of-chance theory to better-than-even cases, a defendant theoretically could be liable for wrongful death in a situation in which it was shown only that there was a 26 percent likelihood that the defendant's negligence was the actual cause of death.

   The problem is best illustrated by the following examples comparing a traditional negligent injury or wrongful death case with a case in which a patient suffers harm as a result of a negligent diagnosis.

   Example A: Negligence resulting in wrongful death. A healthy plaintiff is killed when struck by a negligent automobile driver. To prevail, the decedent's representative must establish two variables--first, that the vehicle was the cause in tact of the death (Variable 1), and second, that a preponderance of the evidence establishes that the vehicle was being operated negligently (Variable 2). Since Variable 1 can be established to a certainty, this example can be illustrated mathematically as follows:

   Variable 1 (cause of death) = 100% = 1.00 Variable 2 (evidence establishing negligence) = 51% = .51 (Variable 1) x (Variable 2) = causation establishing defendant's liability for death (1.00) x (.51) = .51 = 51%

   Here, liability is established because it has been shown that it is more likely than not that the defendant's negligence was the cause in fact of the death. Of course, the mathematical product establishing liability could be significantly higher, to the extent that more than 51 percent of the evidence establishes negligence.

   Example B: Lost chance of survival resulting from misdiagnosis. The plaintiff has a disease from which, at the time he sought treatment, he would have had a 51 percent chance of survival had he been properly diagnosed and treated. Unlike Example A, here a determination of liability involves a number of variables. Variable 1 is the likelihood that the disease would have caused the patient's death irrespective of the negligent diagnosis (100 percent - 51 percent = 49 percent). Variable 2 is the likelihood that the disease caused death possibly in combination with the misdiagnosis (100 percent). Therefore, Variable 3 is the only absolutely quantifiable harm resulting from the misdiagnosis--namely, the loss of a 51 percent chance of survival (100 percent - 49 percent = 51 percent). Variable 4 again is the preponderance of the evidence establishing the alleged negligence.

   Mathematically, this example can be illustrated as follows:

   Variable 3 (chance of survival lost = 51% = .51 Variable 4 (evidence establishing negligence) = 51% = .51 (Variable 3) x (Variable 4) = causation establishing the defendant's liability for death (.51) x (.51) = .26 = 26%

   Here, virtually all courts would find the physician liable for the patient's death, although it can be established that there is a 26 percent likelihood that the negligence was the cause in fact of the death. In so doing, these courts treat the better-than-even chance as though it had materialized or was certain to do so--in other words, not as a chance, but as a certainty.(8)

   Having concluded that the physician's negligence was the cause in fact of the patient's death, courts typically assess damages for the full value of the patient's life, as is the action were one for wrongful death. Again, as in Example A, the mathematical product establishing liability for death could be significantly higher than 26 percent, to the extent that more than 51 percent of the evidence establishes negligence.

2. What To Do

   On a theoretical, but not necessarily practical, level, this problem could be addressed in two ways that would yield a more analytically credible result. The first method would approach the problem only from the...