Evaluation (cont.):

Heuristic EvaluationCognitive Walkthrough

CS352

Announcements

• Presentations of user studies Mon 7/12 (15-20 min each group)

• Project – Concepts and Prototypes due next Thu 7/15 at 11:59pm (presentation next day in class)

• Reading: – Heuristic Eval: Read 15.2 – Cognitive Walkthrough (first-time users): Read

15.3 2

Where we are in PRICPE

• Predispositions: Did this in Project Proposal.• RI: Research was studying users. Hopefully

led to Insights.• CP: Concept and initial (very low-fi)

Prototypes due Monday of Week #6.

Evaluate throughout, repeat iteratively!!

3

Review

• Analytical vs. empirical evaluations• Examples of analytical evaluations?

– GOMS– KLM

Evaluation

• Analytical – based on your head• Empirical – based on data

– Formative • inFORMs design• what is (still) needed?

– Summative • did it work?

Analytical methods

• You follow established guidelines/procedures/models to decide (in your head) how good your design is.

• Examples:– GOMS/KLM – for skilled users.

• evaluating efficiency of regular use.

– Heuristic Evaluation– Cognitive Walkthrough – for first-time users.

• evaluating ease of learning.

Heuristic Evaluation

One of the “Discount Usability” methods• Apply heuristic guidelines (e.g., Nielsen’s)

to a UI to find problems.• Who does it:

– Multiple usability experts.• Default: use Nielsen’s:

– http://www.useit.com/papers/heuristic/heuristic_list.html

“Discount Usability”

http://www.useit.com/papers/guerrilla_hci.html

Heuristic Evaluation• One of the “Discount Usability” methods• Apply heuristic guidelines (e.g., Nielsen’s)

to a UI to find problems.• Who does it:

– Multiple usability experts.• Default: use Nielsen’s:

– http://www.useit.com/papers/heuristic/heuristic_list.html

Nielsen’s 10 Usability Heuristics

1. Visibility of system status

2. Match between system and the real world

3. User control and freedom

4. Consistency and standards

5. Error prevention (e.g., default choice being “Cancel”)

6. Recognition rather than recall

Nielsen’s 10 Usability Heuristics (cont’d)

7. Flexibility and efficiency of use (e.g., short cut keys vs. menus)

8. Aesthetic and minimalist design

Nielsen’s 10 Usability Heuristics (cont’d)

9. Help users recognize, diagnose, and recover from errors

10. Help and documentation (but keep in mind that users do not like to read manuals)

Other examples of heuristics

• Heuristics for ambient displays:– pp. 699-700.

Nabaztag ambient displayhttp://infosthetics.com/archives/2005/10/nabaztag_ambient_email_display.html

Heuristic Evaluation: How

• How:– Pick some usability guidelines, experts, task.– Brief the experts.– Experts indep’ly evaluate UI’s conformance

with those guidelines for that task (1-2 hrs.)• Pass 1: flow.• Pass 2: UI details.• Outcome: UI problems.

– Experts meet to discuss problems, assign priorities, suggest solutions.

Numbers of evaluators for HE

Activity – HE for REI.com• Heuristics for the web:

1. Avoid orphan pages, i.e., pages not connected to homepage

2. Avoid long pages with excessive white space that force scrolling

3. Provide navigation support, such as a strong site map that is always present

4. Avoid narrow, deep, hierarchical menus that force users to burrow deep into the menu structure

5. Avoid non-standard link colors

6. Provide consistent look and feel for navigation and information design

• Pick any three and do a heuristic evaluation – write down problems you find

Cognitive Walkthrough

• “Walk through” the UI, asking yourself questions along the way.

• Who does it:– 1 or more usability experts. (3 is ideal)

• How:– Identify characteristics of user and task.– Make up multiple copies of the Questions

(next slide...)

Cognitive Walkthrough: How (cont.)

• Walk through the task while answering these Questions:– Will the user know what to do? (Gulf of exec)– Will the user see how to do it? (Gulf of exec)– Will the user understand from feedback

whether their action was correct? (Gulf of eval)

Cognitive Walkthrough: How (cont.)

• Record the answers but also:– Assumptions about what would cause the

problems and why.– Notes about side issues.– Notes about possible solutions.

• Example for Amazon.com– pp. 703-704.

Activity• Go to rei.com• Task: buy a pair of skis• For each step, write down:

1. What is the user trying to do?

2. Answer to each of the questions:– Will the user know what to do? (Gulf of exec)– Will the user see how to do it? (Gulf of exec)– Will the user understand from feedback

whether their action was correct? (Gulf of eval)

Comparison

• GOMS/KLM vs. HE vs. CogWalk– how long it takes you to do – how much detail it gives you– about what kind of user