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Don’t make me think!

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Open Day activity for Computing @ University of East London. …

Open Day activity for Computing @ University of East London.

This is a very cut down version of what students are going to study on their second year when taking Usability Engineering.

Introduction to usability evaluation methods & usability testing.

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  • 1. Don’t Make Me Think!Dr. Andres Baravalle
  • 2. Overview• Introduction to usability evaluation methods• Usability testing• Don’t make me think!• Lab activities 2
  • 3. Usability• "The usability of an interface is a measure of the effectiveness, efficiency and satisfaction with which specified users can achieve specified goals in a particular environment with that interface." (ISO 13407). 3 3
  • 4. Effectiveness, efficiency andsatisfaction• Effectiveness: measures if the expected goals have been achieved and measures the accuracy and completeness of the specified goals• Efficiency: measures the effort necessary to achieve the user’s goal and if it is proportionate to the expected result• Satisfaction: measures the pleasantness of using a particular interface and if the interface is suitable or not for the desired goal. 4 4
  • 5. Web Usability: did you knowthat…• People succeed 66% of the time when working on “single site” activities and 60% of the time when having to browse through the internet for information (Nielsen and Loranger, 2006) 5
  • 6. Web Usability: did you knowthat… (2)• Experienced users spend about 25 seconds in a homepage and 45 in an interior page (35 and 60 for inexperienced users)• Only 23% of users scroll on their first visit of a homepage – The number decreases – The average scroll for first visit is 0.8 of a screen 6
  • 7. Web Usability: did you knowthat… (3)• 88% of users go to search engines to find information• Font face and size: different font faces for print and screen – Different font size depending on target audience 7
  • 8. Types of usability evaluation• Three main categories of evaluation methods (Sharp, Rogers and Preece, 2006): – Controlled settings involving users, eg. usability testing & experiments in laboratories and living labs. – Natural settings involving users, eg. field studies (usability inquiry) to see how the product is used in the real world. – Any settings not involving users, eg. consultants critique (usability inspections) and analytical evaluations 8
  • 9. Types of evaluation (2)• In practice, your evaluation protocol will include a set of methods to be used in a complementary way 9
  • 10. Evaluation methods Method Controlled Natural Without settings settings users Observing x x Asking x x users Asking x x experts Testing x Modeling x 10
  • 11. Controlled settings• Controlled settings methods are used to evaluate an artefact by evaluating it on users within controlled settings (e.g. lab) – The focus is on experiments 11 11
  • 12. Natural settings• Natural setting methods focus (at different degrees) on analysing an artefact as used in the natural environment – The focus is on observation 12 12
  • 13. Without users• This category includes all other methods, not requiring direct user involvement• Analytical evaluation methods are based on “dissecting” the interaction with an artefact – They don’t require involving users – E.g. usability inspections and predictive models 13
  • 14. Usability testing 14
  • 15. Usability testing• Involves recording performance of typical users doing typical tasks – Controlled settings – Users are observed and timed – Data is recorded on video & key presses are logged – The data is used to calculate performance times, and to identify & explain errors• User satisfaction is evaluated using questionnaires & interviews 15
  • 16. Testing conditions• Usability lab or other controlled space• Emphasis on: – Selecting representative users – Developing representative tasks• Small sample (5-10 users) typically selected• Tasks usually last no longer than 30 minutes• The test conditions should be the same for every participant 16
  • 17. Some type of data• Time to complete a task• Time to complete a task after a specified time away from the product• Number and type of errors per task• Number of errors per unit of time• Number of navigations to online help or manuals• Number of users making a particular error• Number of users completing task successfully 17
  • 18. How many participants isenough for user testing?• The number is a practical issue• Depends on: – Schedule for testing – Availability of participants – Cost of running tests• Typically 5-10 participants – Some experts argue that testing should continue with additional users until no new insights are gained 18
  • 19. Usability testing methods• The next slides cover some of the methods that are used in usability testing• Some of those methods can be adapted and used for other types of usability evaluations – E.g. Thinking aloud could be adapted to be used in a usability inquiry too 19
  • 20. Thinking aloud• Thinking aloud consists in an interaction (scenario) during which the participants are requested to perform several tasks and to freely express their thoughts, feelings and opinions – Co-discovery is a variation of the thinking aloud method with two user interacting co- operatively – Aims to reflect real-life situations in which users can ask for help from other people 20 20
  • 21. Question asking• Another variation on the Thinking aloud method, in which the evaluator asks the user questions while s/he is performing tasks with the artefact under analysis 21 21
  • 22. Remote testing• Remote testing is used to remotely evaluate an artefact, by gathering quantitative (and in some cases qualitative) data about the user’s behaviour while performing task in a scenario – It is typically used for software interfaces 22 22
  • 23. Don’t make me think!
  • 24. Don’t Make Me Think• The first law of Usability Engineering (according to Steve Krug) is...• Don’t Make Me Think! 24
  • 25. #1: Users don’t read web pages• Users don’t read web pages – they just scan 25
  • 26. #2: Don’t make optimal choices• Optimal choices are in most cases a waste of resources• Typically is not needed to commit the resources needed to have an optimal interface rather than a good interface – People don’t look for perfect plans – they look for good enough plans – Are you really going to look for a second price when you find a book in Amazon at £ 3? 26
  • 27. #3: Users have nounderstanding of how thingswork• Nor they should need to, in many cases – Knowing the TCP/IP stack is not going to help you to send an email• Don’t design interfaces that require learning from users – most probably users are NOT going to learn how to use your interface 27
  • 28. The trunk test• Imagine you are blindfolded in the trunk of a car• Driven around• Dumped somewhere – Once you are out, you need to assess your situation 28
  • 29. The trunk test (2)• A usable web site will allow you to “survive” a trunk test• On a usable web page you’ll be always able to answer these questions: – What site is this – What page I’m on – What are the main sections – What are my options – Where I am – How can I search 29
  • 30. The trunk test (3)• You can use this approach by printing a set of pages and asking users to circle some or all of those areas• You can compare user’s performance on different web pages to have an indicator of their usability 30
  • 31. Designing home pages• A typical home page will include: – Site identity and mission – Site hierarchy – Site search – Teases (e.g. Featured content) – Timely content – Deals (including ads) – Shortcuts to content – Registration• A home page should always pass the “trunk test”! 31
  • 32. Always, always, always TEST• Testing one user is better than testing none! 32
  • 33. Test soon, test often• Testing one user early is better than testing 50 at the end 33
  • 34. Testing is iterative• No point in testing if you don’t correct the errors that you find... 34
  • 35. Why did you add this button tothe user interface? 35
  • 36. References• Nielsen, J. and Loranger, H. (2006). Prioritizing Web Usability.• Krug, S. (2009) Don’t Make Me Think• Sharp, H., Rogers, Y. and Preece, Y. (2007) Interaction Design: Beyond Human-Computer Interaction, 2nd edition, John Wiley & Sons.
  • 37. Lab activities 37
  • 38. Activity 1: throw-away prototypeevaluation• Your team has to develop a mobile web site for UEL students• Develop a paper prototype and test it using the Co-discovery method against users from another team – Refine your prototype and re-test it against another team 38
  • 39. Activity 2: Android music player• Your team has to evaluate the usability of a prototype music player for Android: identify tasks and configuration for a usability test 39
  • 40. Activity 3: Test the Sony webstore• Working as a team, plan a protocol for evaluating Sony’s on-line store: – Identify core tasks that users would typically do on the web site and how to evaluate them – Recommend the configuration (settings – including resolution, browser etc.) for the test• Run the test!

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