The authors compare the appropriateness ratings and mutual influence of panelists from different specialties rating a comprehensive set of indications for six surgical procedures. Nine-member panels rated each procedure: abdominal aortic aneurysm surgery, carotid endarterectomy, cataract surgery, coronary angiography, and coronary artery bypass graft surgery/percutaneous transluminal coronary angioplasty (common panel). Panelists individually rated the appropriateness of indications at home and then discussed and re-rated the indications during a 2-day meeting. Subsequently, they rated the necessity of those indications scored by the group as appropriate. There were 45 panelists, including specialists (either performers of the procedure or members of a related specialty) and primary care providers, all drawn from nominations by their respective specialty societies. Main outcome measures included: individual panelists' mean ratings over all indications, mean change and conformity scores between rounds of ratings, and the percentage of audited actual procedures rated appropriate or necessary. Performers had the highest mean ratings, followed by physicians in related specialties, trailed by primary care providers. One fifth of all actual procedures were for indications rated appropriate by performers and less than appropriate by primary care providers. At the panel meetings, primary care providers and related specialists showed no greater tendency to be influenced by other panelists than did performers. Multispecialty panels provide more divergent viewpoints than panels composed entirely of performers. This divergence means that fewer actual procedures are deemed performed for appropriate or necessary indications.