Usability Evaluation Methods Computer-Mediated Communication Lab week 10; Tuesday 7/11/06

7/11/06 Usability Evaluation Methods 2 Aspects of interaction design The intended user(s) The intended functionality Navigation design  Local structure  Global structure: hierarchical organization  Global structure: dialog Screen design and layout  Visual tools for layout  User action and control  Appropriate appearance

7/11/06 Usability Evaluation Methods 3 Evaluation

7/11/06 Usability Evaluation Methods 4 Usability tests and Expert evaluations “Experienced designers have attained the wisdom and humility to know that extensive testing is a necessity”(Shneiderman 1998) Goals:  Assess extent and accessibility of functionality  Assess users’ experience of the interaction  Identify any specific problems Place:  laboratory  field Moment:  during ‘design life cycle’

7/11/06 Usability Evaluation Methods 5 Types of evaluation methods Experts Analysis ‘Review’ Model Users Experiment Observation Questions Registration

7/11/06 Usability Evaluation Methods 6 Evaluation through expert analysis Cognitive walkthrough  Prototype of system  Representative task description  List of actions needed to complete task  Who are the users, experience and knowledge  For each action, 4 questions Is the effect of the action the same as the user’s goal at that point? Will users see that the action is available? Once users have found the correct action, will they know it is the one they need? After the action is taken, will users understand the feedback they get?

7/11/06 Usability Evaluation Methods 7 Evaluation through expert analysis Heuristic evaluation  Nielsen’s ten heuristics Model-based evaluation  GOMS Using previous studies  Results of experiments

7/11/06 Usability Evaluation Methods 8 Evaluation through user participation Observational techniques  Think aloud and cooperative evaluation  Protocol analysis  Post-task walkthroughs Query techniques  Interviews  Questionnaires Monitoring physiological responses  Eye tracking  Physiological measurements Experimental evaluation  Participants  Hypotheses  Experimental design  Statistical measures

7/11/06 Usability Evaluation Methods 9 Questionnaires SUMI: QUIS: