HEURISTIC EVALUATION WHY AND HOW

Transcription

1 HEURISTIC EVALUATION WHY AND HOW REF: Scott Klemmer Jacob Nielsen James Landay

2 HEURISTIC EVALUATION Multiple ways to evaluate Empirical: Assess with real users trying s/w Formal: Models and formulas to calculate measures how people react to situations Automated: Software measures. Automatic tests. Usually for lower level staff Critique: Expertise and heuristic feedback 2

3 HEURISTIC EVALUATION When to get design critique? Before user testing. Don t waste users on the small stuff. Critique can identify minor issues that can be resolved before testing, allowing users to focus on the big issues. Before redesigning. Critique can help you learn what works and what should change. When you know there are problems, but you need evidence. Perhaps you've received complaints from customers or found yourself stuck around your own site. Critique can help you pin-point problems and provide you with direction for redesign. Before release Smooth off the rough edges. 3

4 HEURISTIC EVALUATION Heuristic Evaluation Developed by Jakob Nielsen Helps find usability problems in a design Small set (3-5) of evaluators examine UI independently check for compliance with usability principles ( heuristics ) different evaluators will find different problems evaluators only communicate afterwards findings are then aggregated Can perform on working UI or sketches 4

5 HEURISTIC EVALUATION Nielsen's Ten Design Heuristics Show system status Familiar metaphors & language User Control & freedom Consistency Error prevention Recognition over recall Flexibility & efficiency Aesthetic & minimalist design Recognize, diagnose, & recover from errors Help and Documentation 5

6 HEURISTIC EVALUATION Evaluators Process Step through design several times Examine details, flow, and architecture Consult list of usability principles..and anything else that comes to mind Which principles? Nielsen s heuristics Category-specific heuristics from e.g., design goals, competitive analysis, existing designs Redesign/fix problems 6

7 HEURISTIC EVALUATION Why Multiple Evaluators? No evaluator finds everything Some find more than others 7

8 HEURISTIC EVALUATION Severe problems found more often Single evaluator achieves poor results only finds 35% of usability problems 5 evaluators find ~ 75% of problems 8

9 HEURISTIC EVALUATION Heuristic Evaluation often faster 1-2 hours each evaluator Heuristic Evaluation results come pre-interpreted Heuristic Evaluation may miss problems & find false positives 9

10 HEURISTIC EVALUATION Phases of Heuristic Evaluation 1. Pre-evaluation training: give evaluators needed domain knowledge and information on the scenario 2. Evaluation: individuals evaluate and then aggregate results 3. Severity rating: determine how severe each problem is (priority). Can do first individually and then as a group 4. Debriefing: review with design team 10

11 HEURISTIC EVALUATION How-to: Heuristic Evaluation At least two passes for each evaluator first to get feel for flow and scope of system second to focus on specific elements If system is walk-up-and-use (e.g. automatic ticket machine) or evaluators are domain experts, no assistance needed otherwise might supply evaluators with scenarios Each evaluator produces list of problems explain why with reference to heuristic or other information be specific and list each problem separately 11

12 HEURISTIC EVALUATION Severity Rating Independently estimate after review Allocate resources to fix problems Estimate need for more usability efforts Severity combines Frequency Impact persistence 12

13 HEURISTIC EVALUATION Severity Ratings 0 - don t agree that this is a usability problem 1 - cosmetic problem 2 - minor usability problem 3 - major usability problem; important to fix 4 - usability catastrophe; imperative to fix 13

14 HEURISTIC EVALUATION Severity Ratings Example Issue: Unable to edit one s weight Severity: 2 Heuristics violated: User control and freedom Description: when you open the app for the first time, you have to enter your weight, but you cannot update it. It could be useful if you mistyped your weight, or if one year or two after the first use of the app, your weight has changed. Courtesy Sebastien Robaszkiewicz, cs

15 HEURISTIC EVALUATION Debriefing Conduct with evaluators, observers, and development team members Discuss general characteristics of UI Suggest potential improvements to address major usability problems Brainstorm solutions 15

16 DESIGN HEURISTICS

17 DESIGN HEURISTICS Ten Design Heuristics Show system status Familiar metaphors & language User Control & freedom Consistency Error prevention Recognition over recall Flexibility & efficiency Aesthetic & minimalist design Recognize, diagnose, & recover from errors Help and Documentation 17

18 DESIGN HEURISTICS Show System Status 18

19 DESIGN HEURISTICS Show: Time Feedback depends on response time <1s: just show outcome ~1s: feedback that activity is underway >>1s: Show fractional progress; time 19

20 DESIGN HEURISTICS 20

21 DESIGN HEURISTICS 21

22 DESIGN HEURISTICS 22

23 DESIGN HEURISTICS 23

24 DESIGN HEURISTICS CONGRATULATIONS! Task Completed 24

25 DESIGN HEURISTICS Familiar Metaphors and Language 25

26 DESIGN HEURISTICS 26

27 DESIGN HEURISTICS 27

28 DESIGN HEURISTICS 28

29 DESIGN HEURISTICS 29

30 DESIGN HEURISTICS User Control & Freedom 30

31 DESIGN HEURISTICS Back Button? 31

32 DESIGN HEURISTICS 32

33 DESIGN HEURISTICS Consistency & Standards 33

34 DESIGN HEURISTICS 34

35 DESIGN HEURISTICS 35

36 DESIGN HEURISTICS 36

37 DESIGN HEURISTICS Error Prevention 37

38 DESIGN HEURISTICS Preview? 38

39 DESIGN HEURISTICS 39

40 DESIGN HEURISTICS 40

41 HEURISTICS Recognition Over Recall 41

42 HEURISTICS 42

43 HEURISTICS \ This Extra Screen here is not appropriate 43

44 HEURISTICS 44

45 HEURISTICS 45

46 HEURISTICS Flexibility & Efficiency 46

47 HEURISTICS 47

48 HEURISTICS 48

49 HEURISTICS 49

50 HEURISTICS 50

51 HEURISTICS 51

52 HEURISTICS 52

53 HEURISTICS Aesthetic & Minimalist Design 53

54 HEURISTICS 54

55 HEURISTICS COLOR SCHEME 55

56 HEURISTICS 56

57 HEURISTICS 57

58 HEURISTICS 58

59 HEURISTICS Recognize, Diagnose, & Recover from Errors 59

60 HEURISTICS 60

61 HEURISTICS WHICH FIELDS??? 61

62 HEURISTICS View to show what is taking space Or Limit the amount of media being saved 62

63 HEURISTICS Show options of different applications to open 63

64 HEURISTICS RELAX CONDITIONS 64

65 HEURISTICS Help 65

66 HEURISTICS 66

67 HEURISTICS TELLS THE PROBLEM AND NOT THE SOLUTION TO IT 67

68 HEURISTICS 68

69 HEURISTICS 69

70 HEURISTICS 70

71 HEURISTICS ATLEAST SUMMARIZE THE AGREEMENT AND NOT ACCEPTING WHITHOUT READING ANYTHING 71