Critical incident reporting systems  (CIRS) can be important for identifying organizational safety needs and lead to reductions in avoidable patient safety events.  A web-based CIRS and training in its use were provided to a network of 69 practices; both qualitative and quantitative assessments of reported incidents and changes in practice teams’ attitudes and processes over 20 months were analyzed for this study. Based on study findings, the authors concluded that before practices can profit from web-based CIRS, they should provide basic training on safety culture and error management and implement an offline CIRS first.