Doctors’ Liability for Patients’ Chances to Recover

Consider the following scenario:

A patient required urgent surgery, which—if performed properly and on time—would have given her a 75% chance of recovery. The doctors negligently delayed the surgery. The delayed surgery promised the patient only a 25% chance of recovery. The surgery was performed impeccably, but the patient still did not recover and she is now permanently incapacitated.  She sues the doctors for malpractice.

Under such circumstances, courts in a number of jurisdictions have held that the patient failed to prove causation by a preponderance of the evidence and dismissed the suit. Reasons underlying this line of authority underscore the patient’s 50% chance not to recover upon receipt of the right treatment. This chance indicates that the proper treatment would have given the patient equal chances to recover and not to recover. Probabilities supporting the parties’ rival claims about causation are equal, and hence the patient failed to establish that her claim is more probable than not (see, e.g., Kilpatrick v. Bryant, 868 S.W.2d 594 (Tenn. 1993).
This line of authority follows the traditional “all or nothing” rule that grants a plaintiff the full amount of compensation upon proof of his case by a preponderance of the evidence, while dismissing every suit that fails to meet this standard.

Other courts have awarded the patient compensation for her lost chance to recover. This compensation equals 50% of the patient’s entire damage (see, e.g., Herskovits v. Group Health Cooperative of Puget Sound 664 P.2d 474 (Wash. 1983); Matsuyama v. Birnbaum, 890 N.E.2d 819 (Mass. 2008)).

Reasons underlying this line of authority include the following:
1) Patients who begin their treatment with a 50% or smaller chance to recover are generally unable to prove causation by a preponderance of the evidence. As a result, they would never be able to successfully sue their doctors for malpractice. Negligent doctors would consequently go scot free. The law of torts will therefore do well to require negligent doctors to compensate the aggrieved patients for their unrealized chances to recover. Absent such requirement, the law would systematically fail to implement its compensation and deterrence objectives.
2) Doctors have a contractual duty to maximize their patients’ chances to recover. When a doctor negligently fails to do so, she breaches her agreement with the patient and must rectify this breach by paying the patient the value of the lost chance.

Each of these lines of authority is misdirected. Contrary to the courts’ view, the probability of the patient’s injury to have resulted from the doctors’ malpractice is 2/3. Under the traditional “preponderance” rule, patient therefore should be awarded the full amount of compensation. Under the lost-chance doctrine, the patient should recover from the doctors 2/3 of her damage.

Here is why:

Over time, the doctors’ malpractice incapacitates 50 patients out of 75. The proper treatment would have cured 75 patients out of 100, but malpractitioners deliver inadequate treatment that cures only 25 patients. Medical malpractice thus permanently incapacitates 75 patients. Of these 75 patients, 50 are victims of the doctors’ malpractice and the remaining 25 patients are not curable. For these 25 patients, the doctors’ malpractice did not change anything.
There is no evidence that could separate the non-curable patients from patients who could be cured by the proper treatment. We therefore must assume that our patient had an equal chance to fall into either of those categories. This assumption originates from the “principle of indifference” upon which statistical calculations routinely proceed. This principle postulates, rather problematically, that the unavailable information is not skewed in either direction (even when there is every reason to believe that it is skewed).  The negligent doctors, however, cannot complain about the fact that this principle is being used because it is their malpractice that made the two categories of patients indistinguishable. Had the doctors treated their patients properly, we would have known which patients were doomed from the beginning and which patients could be cured.

Hence, the patient’s probability of being harmed by the doctors’ malpractice equals 50/75, i.e., 2/3. This probability makes the patient’s causation claim against the doctors more probable than not (>1/2). The patient consequently becomes entitled to full compensation under the preponderance rule.  Under the lost-chance doctrine, the patient should recover 2/3 of her total damage.

For illustrations of how courts systematically err in this area, see Mays v. United States, 608 F. Supp. 1476 (D.C. Colo. 1985) (when doctor’s malpractice reduces patient’s recovery chances from 40% to 15%, patient should receive 25% of her damage); Herskovits v. Group Health Cooperative of Puget Sound 664 P.2d 474 (Wash. 1983) (upon finding that medical malpractice reduced patient’s chances to survive from 39% to 25%, the court held that patient’s widow is entitled to recover 14% of the full compensation amount for wrongful death); McKellips v. Saint Francis Hospital, 741 P.2d 467 (Okla. 1987) (upon finding that medical malpractice reduced patient’s chances to survive from 40% to 25%, the court held that the plaintiff is entitled to recover 15% of the full damage); Alberts v. Schultz, 975 P.2d 1279, 1287 (N.M. 1999) (attesting that when doctor’s malpractice reduces patient’s chance to recover from 50% to 20%, patient should receive 30% of his total damage); Jorgenson v. Vener, 616 N.W.2d 366, 372 (S.D. 2000) (when doctor’s malpractice reduced patient’s chance to recover from 40% to 20%, patient should recover 20% of his total damage); Matsuyama v. Birnbaum, 890 N.E.2d 819 (Mass. 2008) (attesting that when doctor’s malpractice reduces patient’s chances to survive from 45% to 15%, and patient subsequently dies from his illness, the compensation amount for wrongful death should be set at 30%).

For reasons provided above, the patient should have recovered 29% of the total damage in Mays; 19% of the total damage in Herskovits; 20% of the total damage in McKellips; 37.5% of the total damage in the Alberts example; 25% of the total damage in the Jorgenson scenario; and 35% of the total damage in the Matsuyama example.
For more details, see my article with Ariel Porat, Indeterminate Causation and Apportionment of Damages, 23 Oxford Journal of Legal Studies 667 (2003).

Importantly, this way of calculating damages is of consequence in jurisdictions that follow the “all or nothing” rule (e.g., Tennessee).  Consider again the case in which a doctor’s negligence reduces the patient’s chances to survive from 75% to 25%, and the patient dies. Under the courts’ approach, the patient’s lost chance equals 50%, which is below preponderance.  As I explained above, however, the probability of causation here equals 2/3, and hence the plaintiff is entitled to recover the full amount of wrongful-death compensation: her causation claim is more probable than not.

For a recent analysis of the issue that follows the same logic, see Robert Rhee’s article on SSRN.

Incidentally, Israel’s Supreme Court did it right.  After many years of following the American courts’ approach, it decided a case called Frost v. Chirgayev (2008). In that case, the doctor’s malpractice (failure to diagnose cancer) had reduced the patient’s survival chances from 30% to 5%, and the patient died. The Court reasoned that the malpractice moved the deceased from a group of 100 patients of which 30 recover, when treated properly, and 70 die despite proper treatment, to another group of less fortunate patients, of which 95 die and only 5 survive. Because the deceased belongs to the 95 dead people, of which 70 were doomed to die despite proper treatment, her probability of having been killed by the doctor’s malpractice equals 25/95, i.e., 26%. Under the previous system, the plaintiffs would have recovered 1% less: 30%-5%=25%.  This important decision was delivered by Justice Eliezer Rivlin, who writes a lot about torts in his academic capacity. The decision is available here, but you need to know Hebrew in order to read it.