Recent scholarly writing has argued that the advent of managed care within the health policy arena can be seen as a contemporary manifestation of a broader set of concerns focusing on how objective decision procedures become politically legitimated—what one recent commentator has characterized as a faith in the technocratic wish. In the 1990s, this faith in objective decision procedures has manifested itself through the emergence of outcomes assessment and the development of practice guidelines. Notably, a few states have sought to couple the practice guidelines movement with tort reform by enacting demonstration projects permitting physicians to introduce evidence that they followed practice guidelines as an affirmative defense. In this article, I argue that even though the introduction of practice guidelines may promote the policy objective of cost-effectiveness in the delivery of health care services, their use to establish culpability in actual cases may be more difficult because the structure of legal reasoning focuses on the particular facts in the case at hand rather than appealing to abstract decision procedures. By highlighting the potential difficulties of invoking practice guidelines in the adjudication of actual malpractice cases, I demonstrate how a process of ongoing political negotiation will be necessary if the technocratic faith in practice guidelines is to become justified in reality.