Proximate Cause Redefined

April 3, 2023

A committee of the Illinois Supreme Court recently redefined proximate cause, through an amended pattern jury instruction. That instruction — Illinois Pattern Jury Instructions – Civil §15.01 – reads as follows:

When I use the expression “proximate cause,” I mean a cause that, in the natural or ordinary course of events, produced the plaintiff’s injury. It need not be the only cause, nor the last or nearest cause. It is sufficient if it combines with another cause resulting in the injury.

If you decide that the defendant was negligent and that his negligence was a proximate cause of injury to the plaintiff, it is not a defense that something or someone else may also have been a cause of the injury. However, if you decide that the defendant’s conduct was not a proximate cause of the plaintiff’s injury, then your verdict should be for the defendant.

At first blush, this definition does not appear to be the source of any sort of controversy. Yet this revision, which combined three separate instructions on the subject into one, does not refer to a person or entity being the “sole proximate cause” of an injury. The change in the instruction was brought about by a decision in Douglas v. Arlington Park Racecourse LLC, 2018 IL App (1st) 162962. The committee comments on IPI 15.01 point out that Douglas (id. at ¶36) held that “the sole proximate cause theory is simply one way a defendant argues that a plaintiff failed to carry its burden of proof on proximate cause – specifically, by arguing that the negligence of another person or entity, not a party to the lawsuit, was the only proximate cause of the plaintiff’s injuries.” Subsequently, Douglas (id. at ¶58) found that “[the] paramount attribute of the word ‘sole’ is its exclusivity, not its number. Used in the context of ‘sole proximate cause,’ the point is that the group of nonparties are exclusive in the sense that their collective negligence was 100% of the plaintiff’s injury, and the party-defendant’s contribution to the injury was zero. Whether that group consists of 11 nonparties… 2 nonparties… or only a single nonparty is just a detail. Whether one of those nonparties is 100% responsible, or whether the 100% is divvied up among several nonparties, likewise makes no difference.”

A year later, a decision in Doe v. Alexian Brothers Behavioral Health Hospital, 2019 IL App (1st) 180955, expressly rejected the reasoning and holdings of Douglas. Doe (id. at ¶33) agreed with the dissenting opinion issued in Douglas and found that “‘sole proximate cause’ cannot apply to more than one party,” but further held that, “[as] highlighted by… Douglas, without a clear definition, ‘sole proximate cause’ can be a confusing term to a jury.” Doe accordingly ordered a new trial, given that the instructions given, combined with a special interrogatory put to the jury on the subject, caused confusion among jurors.

The committee apparently took that finding to heart when drafting IPI 15.01; per its commentary, the revised instruction was designed “to avoid unnecessary confusion and consternation.” It remains to be seen whether IPI 15.01 accomplishes this in practice; however, litigants and other stakeholders should be aware of the elimination of “sole proximate cause” instructions in Illinois, in favor of the revised IPI 15.01.