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Heuristic Evaluation. Yaser Ghanam. Roadmap. Introduction How it works Advantages Shortcomings Conclusion Exercise. Introduction. Introduced by Nielsen as a discount usability method. Early in the design or during implementation. Given: A prototype or a working system
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Heuristic Evaluation YaserGhanam
Roadmap • Introduction • How it works • Advantages • Shortcomings • Conclusion • Exercise
Introduction • Introduced by Nielsen as a discount usability method. • Early in the design or during implementation. • Given: • A prototype or a working system • A set of usability heuristics • A few evaluators • Come up with: • A usability evaluation of the system
Get the heuristics • Heuristics are system dependent. • Nielsen’s heuristics proved reliable & representative. • Feel free to add more heuristics but not many. • Feel free to drop irrelevant ones.
Usability Heuristics • Visibility of system status
Usability Heuristics • Match between system and the real world
Usability Heuristics • User control and freedom
Usability Heuristics • Consistency and standards Greenberg, S., Overview of Heuristic Evaluation, http://pages.cpsc.ucalgary.ca/~saul/ wiki/uploads/CPSC681/Heuristic.ppt, accessed October 10, 2007.
Usability Heuristics • Error prevention
Usability Heuristics • Help users recognize, diagnose, and recover from errors
Usability Heuristics • Recognition rather than recall
Usability Heuristics • Flexibility and efficiency of use • Shortcuts: • Normal mode vs. Advanced mode • Don’t make it an alternative
Usability Heuristics • Aesthetic and minimalist design
Usability Heuristics • Help and documentation
Get the system ready • Prototype: novel application or interface • No redesign required • Less maintenance later • Working system: replacement study or competition • Prepare typical scenarios: task analysis
Get the evaluators • HE is a group effort. Nielsen, J., and Mack, R.L. (Eds.),Usability Inspection Methods, p25-62. John Wiley & Sons, New York, NY (1994).
Get the evaluators • The more the better? Not necessarily • Rule of thumb: 3 to 5 evaluators Nielsen, J., and Mack, R.L. (Eds.),Usability Inspection Methods, p25-62. John Wiley & Sons, New York, NY (1994).
Get the evaluators • Evaluators’ expertise • Novices: better be potential users of the system • Usability experts: more effective • Double experts (both in usability and the domain): the best to get but very expensive • Session manager: facilitates the evaluation session & aggregates reports • Observers: provide help to evaluators
Do the evaluation • Evaluators get the heuristics & scenarios. • Navigate through the system twice. • Inspect screens, dialogues, forms, messages and menus in the system. • Categorize any problem under one of the heuristics: should give specific explanation. • Can make comments beyond the heuristics. • Report in writing or verbally to the observer.
Do the evaluation • Observers answer evaluators’ questions. • especially domain-specific questions. • but, without influencing judgments. • IMPORTANT: • Inspection should be done individually. • Evaluators are not allowed to communicate. • Session takes 1 to 2 hours.
Compile the results • Aggregate evaluators’ reports. • Eliminate duplicate entries. • Merge different problems. • Output: One report of all usability problems found by the evaluators.
Conduct severity rating • Evaluators are aware of all usability problems. • Severity determined by: • frequency of occurrence • impact on user • persistence
Develop an action plan • Evaluators, facilitator & the design team meet. • Discuss problems . • Suggest solutions. • Consider organization’s priorities. • Take decisions: fix major not minor problems, delay release, replace interface … etc.
Advantages • Discount usability methods: few gives many. • Easy to teach. • Fast to conduct. • Cheap. • Can be used in early design. • High benefit to cost ratio: i.e. 48
Shortcomings • Reduced set of heuristics is very broad and general • Usually does not involve end users • Finds many minor problems causing a “false alarm” sometimes. • Not suitable for in-depth usability testing or critical systems.
Conclusion • A discount usability engineering method. • Best for time-constrained, budget-limited projects. • 3 to 5 evaluators follow 10 heuristics. • Finds many problems in a short time. • Does not replace other usability methods.
ExerciseNielsen, J. (1993). Usability Engineering, 273-274. Academic Press.