By Alex Stein
Three days ago, Washington’s Court of Appeals issued a decision explaining the state’s Supreme Court precedents that entitle patients wronged by their doctors to recover compensation for their lost chances to recover from illness: Herskovits v. Group Health Cooperative of Puget Sound, 664 P.2d 474 (Wash. 1983), and Mohr v. Grantham, 262 P.3d 490 (Wash. 2011). The Court of Appeals ruled that this compensation entitlement is limited to cases in which the injured patient cannot prove causation by a preponderance of the evidence due to her preexisting condition. The Court explained that when a doctor’s malpractice reduces the patient’s chances to recover by more than 50%, the patient would be able to satisfy the preponderance requirement and recover full compensation. The Estate of Ruth M. Dormaier v. Columbia Basin Anesthesia, P.L.L.C., — P.3d —-, 2013 WL 6037098 (Wash.App. Div. 3 2013).
This decision also has continued the prevalent, but mistaken, “arithmetical approach” to lost chances. Under this approach, when a doctor’s malpractice reduces his patient’s chances to recover from illness from 75% to 25%, and the patient ultimately does not recover, the doctor must pay the patient 50% (75%-25%) of her damage.
This approach is mistaken for the following reasons:
In probabilistic terms, the doctor’s malpractice moves the patient from the group of 100 patients, of which 75 recover and 25 do not, to an altogether different group of 100 patients of which only 25 recover and 75 do not. Of these 75 injured patients, 50 are victims of the doctor’s malpractice and the remaining 25 are patients that could not be cured to begin with (and for whom the doctor’s malpractice did not change anything). Hence, the patient’s probability of having been harmed by the doctor’s malpractice equals 50/75, i.e., 2/3. This probability makes the patient’s causation claim against the doctor more probable than not (>1/2). The patient consequently becomes entitled to full compensation under the preponderance requirement.
For illustrations of how courts systematically mishandle lost chances by applying the “arithmetical approach,” 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 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 reduces 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%).
As I explained 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 Ariel Porat & Alex Stein, Indeterminate Causation and Apportionment of Damages, 23 Oxford J. Legal Stud. 667 (2003); Ariel Porat & Alex Stein, Tort Liability Under Uncertainty 124 (2001).
Incidentally, Restatement (Third) of Torts: Physical & Emotional Harm § 26, cmt. n, relied upon by the Court of Appeals, agrees with this criticism of the “arithmetical approach” and with the calculation of lost chances proposed by Ariel Porat and myself. The “arithmetical approach” is only suitable for compensating plaintiffs for the wrongfully imposed risk of future illness or injury, as I explain here and here.