 John researches techniques to improve the design of computer systems with respect to their usefulness and usability.She has investigated the effectiveness and usability of several HCI techniques (e.g., think-aloud usability studies, Cognitive Walkthrough, GOMS) and produced new techniques for bringing usability concerns to the design process (e.g., CPM-GOMS and Usability-Supporting Architectural patterns).Her team at Carnegie Mellon University has developed CogTool, an open-source tool to support Keystroke-Level Model analysis.