The purpose of this study was to review the state of the art of private sector internal error-reporting systems and to begin to develop a classification system for comparing systems. Interviews were conducted to research and examine 9 systems currently on the market. Analysis resulted in the following observations: (1) 7 of the systems are stand-alone, while 2 are part of larger hospital information systems; (2) most of the systems have been in existence for less than 5 years; (3) acute care hospitals are the primary clients; (4) systems are capable of interfacing with other information systems and root-cause analysis programs; and (5) systems are browser based and accessible via the Internet and/or the provider's intranet. Additional studies are needed to determine the impact of these systems on health outcomes. However, one fact is clear: tracking incidents will not improve patient safety unless administrators close the feedback loop on quality.