1 Course updates Ubicomp reading assignment on course web site, due - - PowerPoint PPT Presentation

CS102: Monsoon 2015

CS 102 Human-Computer Interaction Lecture 10: Heuristic Evaluation

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CS102: Monsoon 2015

Course updates

Ubicomp reading assignment on course web site, due next Monday Oct 5, before class User understanding phase: writeup due Monday Oct 12 Hardware requirements for projects? Be sure to review lecture slides, references Experiment for us to receive anon feedback: https:// goo.gl/Vre9dT

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CS102: Monsoon 2015

Recap

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CS102: Monsoon 2015

Human factors in CS

A human-centered design mindset, and skills like user

• bservations, interviews, studies, prototype-and-feedback are

essential In the last 25 years, human factors have entered the loop in nearly all areas of CS e.g. Programming languages, Computer Architecture, Operating systems, Debugging, Databases, Networks, Security, ML, … And of course commercial products as well!

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CS102: Monsoon 2015

Heuristic evaluation

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CS102: Monsoon 2015

Heuristic evaluation

A “discount” usability engineering method A small set of evaluators are independently asked to find “bugs” in interfaces (usually w.r.t recognized usability principles) Different evaluators tend to find different problems Question: How many evaluators should we use?

6 Heuristic Evaluation of User Interfaces

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Experimental setup

4 interfaces with known problems (First 2 were screenshots, last 2 were live systems)

7 Heuristic Evaluation of User Interfaces

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Who finds what?

Savings experiment (37 subjects):

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Problems found

Savings experiment (37 subjects):

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Cost to benefit

10 How to conduct a Heuristic Evaluation

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Takeaways

5 evaluators will find ~ 2/3rd of problems Can use this technique even without a live system

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Which heuristics?

Analysis of 249 usability problems in 11 projects. Each problem checked against 7 sets of guidelines (101 heuristics) Xerox Star, Macintosh, Sunsoft usability guidelines + Molich and Nielsen, Holcomb and Thorp, Polson and Lewis, Carroll and Rosson

12 Enhancing the Explanatory Power of Usability Heuristics

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Broad categories

What are the broad sets of usability problems? 7 buckets:

• Visibility of system status
• Match between system and real world
• User control & freedom
• Consistency and standards

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• Error prevention
• Recognition over recall
• Flexibility and efficiency

Enhancing the Explanatory Power of Usability Heuristics

CS102: Monsoon 2015

Top 10 heuristics

Which heuristics catch how many problems?

14 Enhancing the Explanatory Power of Usability Heuristics

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Best practices

Typically 1-2 hour sessions Either evaluator writes up a report or is observed directly (may be ok for the observer to provide help) Evaluator goes through the interface several times and compares them with a list of heuristics (usability principles) Heuristics based on general + domain-specific guidelines (e.g. derived from competitive analysis)

15 How to conduct a heuristic evaluation

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Nielsen’s 10 heuristics

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Heuristic #1

Visibility of system status

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CS102: Monsoon 2015

Heuristic #1

General guideline:

18 http://asktog.com/atc/principles-of-interaction-design/

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Heuristic #2

Match between system and the real world From a recent citizen’s survey: How important is: Use an outsider to test model of the real world

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Heuristic #3

User control and freedom e.g. cancel button “please don’t close the browser window until the bank transaction is complete” “You weren’t supposed to press that button on this page!”

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Heuristic #4

Consistency and standards Use same L&F Use consistent terminology Predictability of actions, locations of widgets, etc.

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Heuristic #5

Errors: wrong mental model vs. slips: errors in execution Preventing slips: Add constraints that make it difficult to commit them Offer suggestions/auto-complete Use good defaults Be forgiving in syntax

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Heuristic #5

23 http://www.nngroup.com/articles/slips/

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Heuristic #5

For client-server apps: client side checking is ok But in no case should security/data integrity depend on client side checks!

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Heuristic #6

Recognition rather than recall

25 How to conduct a heuristic evaluation

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Heuristic #6

Recognition rather than recall amazon.com

26 How to conduct a heuristic evaluation

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Heuristic #7

Flexibility and efficiency of use

27 How to conduct a heuristic evaluation

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Heuristic #8

Aesthetic and minimalist design Good graphic design (catchall) Keep instructions short

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Heuristic #9

Help users recognize, diagnose and recover from errors Think from user’s point of view: provide actionable advice Restate exactly what happened Shift blame to yourself Error has to be understandable by user/and or operator Hide technical details (stack trace) until requested

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Heuristic #9

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CS102: Monsoon 2015

Heuristic #10

Provision of help and documentation Help should be: Searchable Context-sensitive Task-oriented Concrete Short

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In-class exercise

• 1. Visibility of system status
• 2. Match between system and real world
• 3. User control and freedom
• 4. Consistency and standards
• 5. Preventing errors
• 6. Recognition over recall
• 7. Flexibility and efficiency
• 8. Aesthetic and minimalist design
• 9. Recover from errors
• 10. Help and Documentation

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