Practice parameters: strategies for survival into the nineties.

In an atmosphere of escalating medical costs, clinical practice guidelines have been proposed as a viable means of achieving cost containment. The approaches to developing standards of practice have historically been varied, and new methods of development have been proposed to incorporate current scientific knowledge and patient preferences for achieving optimal health outcomes. We review the historical, governmental, and health organization approaches to achieve scientifically sound and clinically relevant parameters. The mechanism and the mission of the American Academy of Neurology Quality Standards Subcommittee is reviewed. The Subcommittee has selected the term "practice parameter" in lieu of "practice policy" to be consistent with AMA terminology. Practice parameters may include one or more of the following types of recommendations: standards, guidelines, and options. These three terms reflect varying levels of clinical certainty as determined by the level of objective evidence.