Measuring the necessity of medical procedures.

This is a report on the extension of the concept of the appropriateness of a procedure to the necessity, or crucial importance, of that procedure. To state that a procedure is crucial means that withholding the procedure would be deleterious to the patient's health. Appropriateness and necessity ratings for six procedures were obtained using a modified Delphi panel process developed in earlier work. Panels were composed of practicing clinicians who were recognized leaders in their fields. The panels included both performers and nonperformers of the procedure under discussion. For most procedures and panelists, necessity was related to appropriateness, but was distinct from it. The proportion of indications for which the procedure was crucial varied in clinically consistent ways both among and within procedures. However, panelists did not achieve a consensus on necessity. Further research is suggested to refine the method to promote consensus and to validate further the ratings of necessity. In conclusion, necessity ratings can be used together with appropriateness ratings to address not only the overuse of procedures, but also to indicate limited access to care through underuse of procedures.