1. Formative Evaluation cs3724: HCI

2. Problem scenarios summative evaluation Information scenarios claims about current practice analysis of stakeholders, field studies Usability specifications Activity scenarios Interaction scenarios iterative analysis of usability claims and re-design metaphors, information technology, HCI theory, guidelines formative evaluation DESIGN ANALYZE PROTOTYPE & EVALUATE Scenario-Based Design

3. Usability Engineering Reqs Analysis Evaluate Design Prototype

4. Usability Engineering Reqs Analysis Evaluate many iterations Design Develop

5. Usability Engineering Formative evaluation Summative evaluation

6. User Interface Metrics Ease of learning learning time, … Ease of use perf time, error rates… User satisfaction surveys… Not “user friendly”

7. Claims Analysis + advantages - disadvantages E.g. file management: + +

8. Claims Analysis + advantages - disadvantages E.g. file management: + fast learning + spatial learning aid memory - switching between devices - long to locate a known file… + flexible, power + fast for experts - Learning commands - aesthetics lacking?...

9. Usability Evaluation Analytic Methods: Heuristic Evaluation Models: GOMS, Fitts Law Empirical Methods: Usability Testing –Wizard of Oz Controlled Experiment

10. Nielsen’s 10 Heuristics 1.Visible status, feedback 2.User control, undo, exits 3.Familiar, speak user’s language 4.Consistent, standards 5.Recognition over recall 6.Efficient, expert shortcuts 7.Aesthetic, minimalist 8.Prevent errors 9.Error recovery 10.Help, task-based

11. Nielsen’s 10 Heuristics 1.Visible status, feedback wysiwyg 2.User control, undo, exits wizards 3.Familiar, speak user’s language Acrobat error msg 4.Consistent, standards Word, PPT 5.Recognition over recall web nav, phone menu 6.Efficient, expert shortcuts Word bold 7.Aesthetic, minimalist phone book 8.Prevent errors HomeFinder 9.Error recovery undo, back 10.Help, task-based IIS help doc

12. Speak the User’s Language

13. Help documentation Context help, help doc, UI

14. Applying Heuristics Lets look at a website…

15. Early Usability Testing Formative: helps guide design Early in design process when architecture is finalized, then its too late! A few users (3-5) Identify usability problems, incidents Qualitative feedback from users Quantitative usability measures

16. Usability Test Procedure Wizard of Oz: act out the system Benchmark task set No cheating! Don’t teach them how to use the UI Repeat: Give user a task Ask user to “think aloud” Observe, note mistakes and problems Avoid interfering, hint only if completely stuck Interview Verbal feedback Questionnaire 30 min - 1 hour / user

17. Analyze Results Initial reaction: “stupid user!”, “that’s developer X’s fault!”, “this sucks” Mature reaction: “how can we redesign UI to solve that usability problem?” the user is always ‘right’ Identify usability problems Learning issues: e.g. can’t figure out or didn’t notice feature Performance issues: e.g. arduous, tiring to solve tasks Subjective issues: e.g. annoying, ugly Problem severity: critical vs. minor Redesign

18. Pizza Ordering System Scenario: Volunteers! Design ideas Wizard of Oz usability test Redesign

20. In action: Pizza Ordering System Scenario: VT students, studying/busy/tired, poor, wants discounts, starving, credit card / hokie card/ no cash, 2 in together, half-n-half, split cost Volunteers! Design ideas Wizard of Oz usability test Redesign

21. Pizza R Us peperoni mushrooms pineapple Whole Half-n-half PRICE: $10.00 Drag your toppings: checkout

22. Size of pizza: –large –Small First half: Toppings: –Peperoni –Mushrooms –Pineapple Price: 0.00 2 nd half: Toppings: –Peperoni –Mushrooms –pineapple

23. % pza –ppm –large -…