NOTICE: The project that is the subject of this interim statement was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the interim statement were chosen for their special competencies and with regard for appropriate balance.

This interim statement has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine.

The Institute of Medicine was chartered in 1970 by the National Academy of Sciences to enlist distinguished members of the appropriate professions in the examination of policy matters pertaining to the health of the public. In this, the Institute acts under both the Academy's 1863 congressional charter responsibility to be an adviser to the federal government and its own initiative in identifying issues of medical care, research, and education. Dr. Kenneth I. Shine is president of the Institute of Medicine.

Support of this project was provided by the Agency for Health Care Policy and Research, U.S. Department of Health and Human Services, under Contract No. 282-94-2008. Additional funds were provided by the Baxter Foundation.

Additional copies of this report are available in limited quantities from:

Division of Health Care Services

Institute of Medicine

2101 Constitution Avenue, N.W.

Washington, D.C. 20418

The serpent has been a symbol of long life, healing, and knowledge among almost all cultures and religions since the beginning of recorded history. The image adopted as a logotype by the Institute of Medicine is based on relief carving from ancient Greece, now held by the Staalichemuseen in Berlin.