Human factors engineering studies how users interact with technology and attempts to optimize systems to minimize unintended consequences in real-world usage. Computerized provider order entry (CPOE) systems offer considerable safety advantages, but in real-world situations, many CPOE systems have failed to achieve the anticipated results. This Australian study found that many clinicians did not use CPOE system features that were intended to improve efficiency and safety, possibly because doing so would have forced them to change their workflow substantially. This non-standard usage resulted in the generation of many clinically irrelevant alerts, likely contributing to alert fatigue and probably diminishing the overall safety performance of the system. The study highlights the need for usability testing and careful integration of new technology into existing clinician workflows.