An influential 2010 report called for revision of medical education curricula to incorporate patient safety concepts, terming the issue an "unmet need." A recent systematic review found that while safety curricula generally improved trainees' patient safety knowledge, the optimal method for teaching these concepts remains unclear. This randomized trial compared the efficacy of two different types of online education at improving knowledge of the National Patient Safety Goals and incorporating this knowledge into practice. Spaced education, a technique involving repeated interactive online educational encounters spaced over time, was found to be more effective than standard online modules in improving residents' knowledge and adherence to specific procedural safety techniques. As online education becomes more popular in general, this study provides evidence for spaced education as an effective way to communicate patient safety concepts.