Since Bates’s seminal study in 1998, several other investigators have examined the impact of CPOE adoption on the incidence of medication errors. Overall, these studies suggest that CPOE has benefits, but they also illustrate substantial barriers to its successful implementation and adoption. A systematic review by Reckmann and colleagues concluded that “the amount of evidence is very modest and the quality and generalizability of results is limited.” The review highlighted the variety of outcome measures used to evaluate CPOE systems, as well as differences in measure specifications for related outcomes (Reckmann, Westbrook, et al., 2009). This variability appears to have contributed to uncertainty about the overall impact of CPOE among hospitals and physician practices that were considering adoption. Some studies reported many challenges related to CPOE implementation in some settings. Some also reported instances of negative effects of CPOE (Kashani and Barold, 2005; Koppel, Metlay, et al., 2005; Sittig, Ash, et al., 2006). The evidence on CPOE implementation problems has tended to indicate issues with system design and the methods used to introduce CPOE into various settings (Ash, Stavri, et al., 2003). Poorly designed systems, poorly conceived implementation plans, and inadequate integration of CPOE into physician workflow may have accounted for the limited effectiveness of CPOE in other studies.