To the Editor.—
Dr Brook's1 article on practice guidelines was intriguing. In it, he recommends that guidelines be used by insurers to deny reimbursement, by courts to rule on malpractice decisions, by licensure boards to issue credentials, by professional societies to approve recertification, and by patients and employers to select providers.These sweeping recommendations may be premature. We have yet to reach agreement on how to define appropriateness accurately. Undisputed guidelines can only be set for some procedures and for flagrant departures from accepted standards of care, but for much of medicine we lack measures of appropriateness that are clinically and scientifically valid.The RAND Corporation's methodology discussed by Dr Brook is an important step forward, but its precision is uncertnain. Fundamental questions remain about the validity of deciding appropriateness by expert consensus. Opinions of inappropriateness set into generic guidelines may not equate with true inappropriateness in individual cases.