A case of a sudden increase in reports of a specific error in the anatomic pathology laboratory is evaluated, yielding insights into the value, challenges, and limitations of using error reports as a quality management tool. The discussion considers the utility of a robust error-reporting system for anatomic pathology laboratories and identifies key factors at each step to improve success. Initial reporting must be easy and rewarding to reporters, and they must have confidence that reporting will not result in adverse impacts on coworkers. Categorization of common errors simplifies reporting, investigation, tracking, and data presentation. Response to errors should focus on addressing system design failures, while also providing nonjudgmental, nonpunitive feedback to individuals. Error categories can be chosen for systematic quality improvement projects based on severity and frequency of the error. When monitoring trends in error data, it is important to remember that the data are very sensitive to changes in reporting rates as well as changes in error rates, so they must be interpreted with great caution.