This study reports on the experiences of a Massachusetts statewide collaborative to improve patient safety. The chosen interventions were medication reconciliation and prompt communication of critical test results, which were selected by an advisory committee of stakeholders advised by national opinion leaders. Each participating hospital sent a multidisciplinary team to four collaborative meetings, at which participants learned Plan-Do-Study-Act (PDSA) methodology and implementation strategies and later returned to share experiences and data. The project successfully enrolled 88% of acute care hospitals in the state, but only 50% of hospitals successfully implemented medication reconciliation, and 65% implemented communication of critical test results. Major barriers to implementation included lack of dedicated staff time and lack of support from hospital management. The investigators also identified problems with the collaborative process itself, chiefly, failure to define clear expectations and failure to emphasize measuring data to monitor efficacy.