The patient safety risks associated with handoffs have been well documented. As a result, multiple investigators have developed standardized tools to improve the quality of information transfer during handoffs. What remains unclear is the extent to which standardizing the handoff process improves patient safety. This systematic review of 36 studies examining the effectiveness of handoff tools found that most tools were not evaluated rigorously and did not specifically assess the effect of standardizing handoffs on patient-level outcomes. Therefore, the authors were unable to reach conclusions regarding the optimal methods for improving the quality of handoffs. Similar problems were noted in studies of checklists, another widely implemented safety intervention, highlighting both the difficulty and the importance of strictly evaluating patient safety interventions.