Impact of a Risk Calculator on Risk Perception and Surgical Decision Making

A Randomized Trial

Published in: Annals of Surgery, 2016

Posted on on July 25, 2016

by Greg D. Sacks, Aaron J. Dawes, Susan L. Ettner, Robert H. Brook, Craig Fox, Marcia M. Russell, Clifford Y. Ko, Melinda Maggard Gibbons


The aim of this study was to determine whether exposure to data from a risk calculator influences surgeons' assessments of risk and in turn, their decisions to operate.


Little is known about how risk calculators inform clinical judgment and decision-making.


We asked a national sample of surgeons to assess the risks (probability of serious complications or death) and benefits (recovery) of operative and nonoperative management and to rate their likelihood of recommending an operation (5-point scale) for 4 detailed clinical vignettes wherein the best treatment strategy was uncertain. Surgeons were randomized to the clinical vignettes alone (control group; n = 384) or supplemented by data from a risk calculator (risk calculator group; n = 395). We compared surgeons' judgments and decisions between the groups.


Surgeons exposed to the risk calculator judged levels of operative risk that more closely approximated the risk calculator value (RCV) compared with surgeons in the control group [mesenteric ischemia: 43.7% vs 64.6%, P < 0.001 (RCV = 25%); gastrointestinal bleed: 47.7% vs 53.4%, P < 0.001 (RCV = 38%); small bowel obstruction: 13.6% vs 17.5%, P < 0.001 (RCV = 14%); appendicitis: 13.4% vs 24.4%, P < 0.001 (RCV = 5%)]. Surgeons exposed to the risk calculator also varied less in their assessment of operative risk (standard deviations: mesenteric ischemia 20.2% vs 23.2%, P = 0.01; gastrointestinal bleed 17.4% vs 24.1%, P < 0.001; small bowel obstruction 10.6% vs 14.9%, P < 0.001; appendicitis 15.2% vs 21.8%, P < 0.001). However, averaged across the 4 vignettes, the 2 groups did not differ in their reported likelihood of recommending an operation (mean 3.7 vs 3.7, P = 0.76).


Exposure to risk calculator data leads to less varied and more accurate judgments of operative risk among surgeons, and thus may help inform discussions of treatment options between surgeons and patients. Interestingly, it did not alter their reported likelihood of recommending an operation.

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