The law frequently derives its content from the practices of the community it regulates. Examples are legion: Tort’s reasonable care standard demands that we all exercise the prudence of an “ordinary” person. Ambiguous contracts find meaning in the custom and usage of trade. The Fourth Amendment examines our collective expectations of privacy. And so on. This recourse to real-world circumstance has intuitive appeal, in that it helps courts resolve fact-dependent disputes and lends legitimacy to their judgments.
Yet real-world practice can depart from that which the law expects. For example, suppose a physician provides more-than-reasonable care—extra tests, unneeded procedures, etc.—so as to steer clear of tort liability’s considerable gray area. If other physicians follow suit, their precautions slowly but surely become the new legal norm, as the reasonable care standard dutifully absorbs the conduct of those it governs. Instead of discouraging wasteful practices, the law feeds them back into doctrine, making overcompliance into mere compliance and ratcheting up the standard of care. Overcautious physicians then have to do even more to steer clear of liability, and the cycle begins anew.
This Article provides a general model of this “doctrinal feedback” phenomenon and then applies it to medical malpractice, where tort’s reasonable care standard has caused an unhealthy and unappreciated feedback effect and has led the law to require an unreasonable level of care. In doing so, it reveals feedback’s surprisingly common formative factors and demonstrates its potential to skew legal norms in a variety of otherwise dissimilar fields.