Ch 11 Cognitive Walkthroughs and Heuristic Evaluation

1. Ch 11 Cognitive Walkthroughs and Heuristic Evaluation Yonglei Tao School of Computing and Info Systems GVSU

2. Heuristic Evaluation • Usability experts evaluates an interface according to a set of criteria • Follow a scenario through the design • Identify problem users would have when interacting with the interface • Make recommendations • Nielsen’s ten huristics www.useit.com/papers/heuristic/heuristic_list.html

3. Empirical Data Factor 1: Visibility of system status • Feedback: keep user informed about what goes on • Provide status information • Feedback: show that input has been received • Features change as user carries out task • Feedback provided for all actions • Feedback timely and accurate • Indicate progress in task performance • Direct manipulation: visible objects, visible results • Identity cues system response vs. user’s goals • Show icons and other visual indicators • WYSIWYG: do not hide features • What incorrect inferences are most likely

4. Empirical Data (Cont.) Factor 2: Match between system and real world • Speak the user’s language • Contains familiar terms and natural language • Speak the user’s language • Metaphors from the real world • Familiar user’s conceptual model • Use of user’s background knowledge • Learnable through natural, conceptual model • Follow real-world conventions • Screen representation matches non-computer • Encourage users to import pre-existing tasks • Identity cues between actions and user’s goals • Understand the user’s language

5. Empirical Data (Cont.) Factor 3: User control and freedom • Undo and redo should be supported • Obvious way to undo actions • Forgiveness: make actions reversible • Ability to undo prior commands • Clearly marked exits • Ability to re-order or cancel tasks • Modeless interaction • User control: allow user to initiate/control actions • Modelessness: allow users to do what they want

6. Empirical Data (Cont.) Factor 4: Consistency and standards • Consistency: express same thing same way • Consistency • Consistency: same things look the same • Uniform command syntax • Conform to platform interface conventions • Consistent key definitions throughout • Universal commands: a few, generic commands • Show similar info at same place on each screen

7. Empirical Data (Cont.) Factor 5: Error prevention • Prevent errors from occurring in the first place • System designed to prevent errors • Understand the user’s language • What planning mistakes are most likely? • What slips are most likely? • Identity cues between actions and user’s goals

8. Empirical Data (Cont.) Factor 6: Recognition rather than recall • See-and-point instead of remember-and-type • Make the repertoire of available actions salient • Seeing and pointing: objects and actions visible • All user needs accessible through the GUI • What features often missed and at what cost? • Provide lists of choices and picking from lists • Minimize the users’ memory load • Direct manipulation: visible objects, visible results • Easy or difficult to perform (execute) task? • Evoke goals in the user • Allow access to operations from other apps. • Clearly marked exits • Show icons and other visual indicators • Integrated with the rest of the desktop

9. Empirical Data (Cont.) Factor 7: Flexibility and efficiency of use • Accelerators should be provided • Shortcuts: Accelerators to speed up dialogue • User tailorability to speed up frequent actions • User control: allow user to initiate/control actions • System should be efficient to use • User interface should be customizable • Ability to re-order or cancel tasks • Keyboard core functions should be supported • Physical interaction with system feels natural

10. Interactive Heuristic Evaluation Toolkit • Allows you to do either of the following:- View a list of the suggested heuristics for a particular type of electronic device, or- Select your own heuristics for a type of device and then compare your selections against a list of suggested heuristics http://www.id-book.com/catherb/

11. Cognitive Walkthroughs • An evaluator steps through the action sequence for a task and check the design for potential usability problems • Role-plays the part of a typical user and tries to accomplish that user’s tasks

12. Cognitive Walkthroughs • Questions to ask at each step • Will users know what to do? • Will users see how to do? • Will users understand from feedback whether the action was correct or not?

13. Example of Cognitive Walkthroughs

14. Example of Cognitive Walkthroughs

15. A Scenario – Read Poems from Multiple Issues • From the Home page, click on the Issues link • From the Issues page, decide on an issue to look at • Click on the appropriate issue link • Scan the TOC for a poem • Click on the poem’s link • Read the poem • Click on the global Issues link • Repeat steps 2-6