Computerized provider order entry (CPOE) has provided significant safety benefits in research studies, especially when combined with clinical decision support to prevent common prescribing errors. However, CPOE's "real-world" performance has been mixed, with high-profile studies documenting a variety of unintended consequences. This AHRQ-funded study used simulated patient records to evaluate the ability of eight commercial CPOE modules to prevent medication errors. The overall results were disappointing, as CPOE failed to prevent many medication errors—including fully half of potentially fatal errors, which are considered never events. The individual CPOE products varied significantly in their ability to detect potential errors. Some hospitals did achieve superior performance, which the authors ascribe to greater experience with CPOE and implementation of more advanced decision support tools. Another recent article found that reminders within CPOE systems resulted in only small improvements in adherence to recommended care processes. Taken together, these studies imply that CPOE implementation may not result in large immediate effects on safety and quality in typical practice settings.