April 2007

Document Type


Degree Name



Dept. of Biomedical Informatics and Clinical Epidemiology


Oregon Health & Science University


BACKGROUND: Overly simplistic or complex user interfaces of Computerized Provider Order Entry (CPOE) systems may impede clinical efficiency and the decision making process by increasing cognitive load and diverting physicians' attention from the clinical task at hand. In order to design better healthcare user interfaces, there is an imperative need for developing new evaluation methodologies to quantify the cognitive complexity of CPOE user interfaces. OBJECTIVES: To propose a method for quantitative measurement of cognitive complexity of CPOE user interfaces; to validate the developed metrics by characterizing and comparing the cognitive complexity of three CPOE systems; to gather preliminary usability data that can be correlated to quantitative estimations of cognitive load of user interfaces. METHOD: A quantitative analysis of cognitive complexity of CPOE user interfaces was performed by computing thirteen design metrics. This analysis was followed by a usability order entry study involving a total of 30 experienced clinician users of the three CPOE systems investigated. Study participants were timed as they entered seven generic orders in each system; various ordering issues were identified. Participants also completed a short survey regarding their computer skills as well as their experience and satisfaction with using CPOE systems. RESULTS: The quantitative evaluation showed a measurable difference in cognitive complexity between the three CPOE user interfaces. Furthermore, the usability study established that participants spent more time and were less satisfied with using an overly complex CPOE system than a system with a lower cognitive complexity score.




School of Medicine



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