Most patient safety problems can be ascribed to underlying systems failures, but issues with individual clinicians play a role as well. Prior studies have shown that a small proportion of physicians account for a disproportionate share of patient complaints and malpractice lawsuits. This retrospective cohort study used data from the Patient Advocacy Reporting System (which collects unsolicited patient concerns) and the National Surgical Quality Improvement Program to examine the association between patient complaints and surgical adverse events. The investigators found that patients of surgeons who had received unsolicited patient concerns via the reporting system were at increased risk of postoperative complications and hospital readmission after surgery. Although the absolute increase in complication rates was relatively small across all surgeons, surgeons in the highest quartile of unsolicited observations had an approximately 14% higher risk of complications compared to surgeons in the lowest quartile. This study extends upon prior research by demonstrating an association between patient concerns about individual clinicians and clinical adverse events, and it strengthens the argument for using data on patient concerns to identify and address problem clinicians before patients are harmed.