andomizedclinicaltrials(RCTs)serveasthegoldstandardand represent the highest level of evidence for the determination of optimal and effective treatment strategies in evidencebased medicine for patients, particularly in terms of statistical reliability. Methods used in RCTs decrease selection bias and minimize confounding, which promote their ability to establish causation.Clinicians evaluating RCT results in an effort to provide optimal patient care frequently rely on rejection of the null hypothesis, with a P value threshold of less than .05 and appropriate 95% CIs used to determine statistical significance and confirm a positive outcome. These positive findings from RCTs frequently lead to substantial changes in clinical practice and patient care. Yet methodologists have noted that medical research studies should not be interpreted from P values alone, [1][2][3][4] noting that a "high rate of non-replication (lack of confirmation) of research discoveries is a consequence of the convenient, yet ill-founded strategy of claiming conclusive research findings solely on the basis of a single study assessed by formal statistical significance, typically for a p-value less than 0.05." 2(pe124) The Fragility Index (FI) is an important aid in the interpretation of clinical trial results. 5 The FI aids in determination of when statistical sig-nificance in a clinical trial may be lost as a result of a shift of a few additional events from the experimental group to the control group. 6 No matter what threshold P value is chosen, the FI score will still serve as an additional metric to demonstrate how easily statistical significance may be exceeded. Use of the FI can aid physicians in identifying trials that may be at risk of being overturned by future studies and avoiding overestimating the significance of RCT results. This narrative review discusses the definition and calculation of the FI and Fragility Quotient (FQ) scores, use in the interpretation of medical and surgical RCTs, a detailed review of FI scores in trauma RCTs, and discussion of the importance of this statistic in the development of national clinical guidelines. It provides a framework for surgeons to use the FI in the assessment of RCTs to ultimately provide optimal surgical patient care.