This review discusses the wide range of available methods to study quality improvement projects. The authors provide a framework for evaluating work of this nature and focus specifically on quantitative designs. They discuss the nuances of selecting randomized versus non-randomized approaches and the tradeoffs of each approach for evaluating a given intervention. Numerous examples are included that offer insight into the challenges of measuring effectiveness in quality improvement efforts. The authors advocate for selecting an evaluation strategy that meets the needs and available resources of a given project while minimizing bias and maximizing generalizability. The review and accompanying discussion apply directly to work in patient safety, which shares the same challenges in evaluation design.