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Usability and Accessibility Lecture 1 – 09/02/10

Usability and Accessibility Lecture 1 – 09/02/10. Dr. Simeon Keates. Course (provisional) overview. Note: subject to change!. Weeks 1 + 2: Project – done! Week 3: Intro to usability Week 4: Discount usability Week 5: Guest lectures Weeks 6-8: Universal access

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Usability and Accessibility Lecture 1 – 09/02/10

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  1. Usability and AccessibilityLecture 1 – 09/02/10 Dr. Simeon Keates

  2. Course (provisional) overview Note: subject to change! • Weeks 1 + 2: Project – done! • Week 3: Intro to usability • Week 4: Discount usability • Week 5: Guest lectures • Weeks 6-8: Universal access • Weeks 9-10: User studies • Week 11: Case studies / guest lecture • Week 12: Usability and businesses • Weeks 13-14: Complete project • Week 15: Hand in reports

  3. Initial design feedback • All groups completed the task • Reports had very different styles • What each group thinks is important • Interesting variety of design rationales • What matters to different groups • Product classifications vs. list • More on this in Friday’s exercise • Sorting options…

  4. Course aim Usual answer: • To introduce and explore a toolkit of usability methods and techniques • We will be doing this Additional (better?) answers: • To teach you to think for yourselves • To teach critical thinking • Classic ice cream/drowning example

  5. Ice cream causes drowning! • The number of deaths due to drowning is higher on days when ice cream sales are high • The number of deaths due to drowning is lower on days when ice cream sales are low • Deaths by drowning and ice cream sales are strongly correlated • Eating ice cream increases your chances of drowning! Is this conclusion correct???

  6. A quick definition… • “Product” • Product • System • Service • Web-site

  7. What will we be looking at… • Project is web-based • For ease of coding… • Most examples will be software-based or web-based • Easier for experimentation… • Methods are extendable to hardware products • Some examples…

  8. EPIRAID office workstation

  9. The IRVIS prototype

  10. The Personal Information Point More on this later today…

  11. The “Your Guide” kiosk and surround

  12. Analogue teletext / television

  13. Digital teletext / television

  14. Getting started…What is “usability”?

  15. Usability… • Q – What makes a “good” product? • Q – What makes a “better” product? • Q – How do you define “usability” and “accessibility”? • Q – When should usability be considered in the design process? • Q – When is a product OK to release to customers? • Q – How do you define “sufficiently” usable?

  16. Why is usability important? (source: Patrick Jordan “An introduction to usability) • Annoyance • Products that are difficult to use cause annoyance and frustration and can defeat their original purpose • Financial implications (product sales) • People do not want to buy those products • Financial implications (productivity) • People who have to use those products do not work as effectively and efficiently as they should • Safety • Three Mile Island – officially “human error” but Norman claims bad design led to misdiagnosis of what was happening in the reactor

  17. How do you define “usability”? • Suggestions? Typical answers: • “The ability to get to a product’s functionality” • “The ability to use a product successfully” • “Intuitiveness / ease of learning” • “Ease of use” • “User friendliness” We need something more concrete… … and usable …

  18. How do you define “usability”? (source: Wikipedia “Usability” entry) Ben Shneiderman and Jakob Nielsen (writing separately) claimed: Usability is a part of “usefulness” and is composed of: • Learnability: • How easy is it for users to accomplish basic tasks the first time they encounter the design? • Efficiency: • Once users have learned the design, how quickly can they perform tasks? • Memorability: • When users return to the design after a period of not using it, how easily can they re-establish proficiency? • Errors: • How many errors do users make, how severe are these errors, and how easily can they recover from the errors? • Satisfaction: • How pleasant is it to use the design?

  19. How do you define “usability”? (source: Patrick Jordan “An introduction to usability) • Guessability: • The effectiveness, efficiency and satisfaction with which specified users can complete specified tasks with a specified product for the first time • Learnability: • The effectiveness, efficiency and satisfaction with which specified users can achieve a competent level of performance on specified tasks with a specified product, having completed those tasks once previously • Experienced user performance: • The effectiveness, efficiency and satisfaction with which specified experienced users can achieve specified tasks with a specified product

  20. How do you define “usability”? (source: Patrick Jordan “An introduction to usability) • System potential: • The optimum level of effectiveness, efficiency and satisfaction with which it would be possible to complete specified tasks with a specified product • Re-usability: • The effectiveness, efficiency and satisfaction with which specified users can achieve specified tasks with a specified product, after a comparatively long period away from those tasks

  21. How do you define “usability”? (source: ISO 9241-11) ISO 9241 definition: • “The effectiveness, efficiencyand satisfactionwith which specified users achieve specified goals in particular environments” • effectiveness: the accuracy and completeness with which specified users can achieve specified goals in particular environments • efficiency: the resources expended in relation to the accuracy and completeness of goals achieved • satisfaction: the comfort and acceptability of the work system to its users and other people affected by its use

  22. Measuring usability (source: Patrick Jordan “An introduction to usability) Effectiveness: the extent to which a goal or task is achieved • Task completion: • How much got done? • Quality of output: • Was what got done any good?

  23. Measuring usability (source: Patrick Jordan “An introduction to usability) Efficiency: the amount of effort to accomplish a goal • Deviations from the critical (i.e. shortest) path: • How much did the user wander? • Error rate: • How often did the user make a mistake? How “bad” were the mistakes? • [More on this on Friday] • Time on task: • How long did it take? • Mental workload: • How hard did the user have to think?

  24. Measuring usability (source: Patrick Jordan “An introduction to usability) Satisfaction: the level of comfort that the user feels when using a product and how acceptable the product is to users as a vehicle for achieving their goals • Qualitative attitude analysis: • Did you like it? • Quantitative attitude analysis: • How much did you like it? (e.g. benchmarking)

  25. IMPORTANT POINT #1 • Most definitions involve: • Effectiveness • Efficiency • Satisfaction • Q – Are these definitions mutually exclusive??? • To be useful, usability needs to be quantifiable • And thus measurable…

  26. Typical usability considerations (source: Wikipedia “Usability” entry) Usability includes considerations such as: • Who are the users, what do they know, and what can they learn? • What do users want or need to do? • What is the general background of the users? • What is the context in which the user is working? • What has to be left to the machine? Answers to these can be obtained by conducting user and task analysis at the start of the project.

  27. Typical usability considerations (source: Wikipedia “Usability” entry) • Can users “easily” accomplish their intended tasks? • For example, can users accomplish intended tasks at their intended speed? • How much training do users need? • What documentation or other supporting materials are available to help the user? • Can users find the solutions they seek in these materials? • What and how many errors do users make when interacting with the product? • Can the user recover from errors? What do users have to do to recover from errors? Does the product help users recover from errors? • For example, does software present comprehensible, informative, non-threatening error messages? • Are there provisions for meeting the special needs of users with disabilities? (Accessibility)

  28. Getting started…The purpose of “design”

  29. What is the aim of design? – Some common answers • Cheaper • Faster • Cleaner • Safer • Lighter • Smaller, etc.

  30. What is the aim of design? – User perspectives • I want itto do more • I want to be able to use it • I want to be able to understand it • I want to feel in control of it • I want to be able to trust it

  31. What are we aiming for? (Source: Jakob Nielsen “Usability Engineering”) Acceptability Practical acceptability • Utility • Usability

  32. What is the aim of design? – An example

  33. The functional choice…

  34. The aspirational choice…

  35. What are we aiming for? (Source: Jakob Nielsen “Usability Engineering”) Acceptability Practical acceptabilitySocial acceptability Utility Aesthetics Usability Desirability Branding

  36. What is the aim of design? – Some common answers • Cheaper • Everyone wants a Bic biro… | Mont Blanc pens • Faster • Every aeroplane will be Concorde… | Orient Express • Cleaner • Everyone wants a Toyota Prius… | Aston Martin, Ferrari, etc. • Safer • Everyone wants to stay home all day… | Extreme sports • Lighter • Everyone wants to only take hand luggage on holiday… | Jewellery • Smaller • Everyone wants to only take hand luggage on holiday… | Double whopper …

  37. IMPORTANT POINT #2 • There is no single universal product for everyone • There is no single product that will meet everyone’s needs • There is no single product that everyone will want to own • You can often only aim to satisfice • http://en.wikipedia.org/wiki/Satisficing

  38. Designing an acceptable interface

  39. What is a good interface? • Acceptable by the intended user group • (Jakob Nielsen “Usability Engineering”) Need to define: • What is the intendedusergroup? • What is acceptable?

  40. Who are the users? • Often defined by marketing • “Target” users… • Defined by socio-economic factors • For usability can (should) take a broader view • Defined by user needs and wants • i.e. users who should be able to use the product • Accessibility takes an even broader view • [More on that in a few weeks]

  41. What is a good interface? • Acceptable by the intended user group • (Jakob Nielsen “Usability Engineering”) Need to define: • What is the intendedusergroup? • What is acceptable?

  42. Designing an acceptable interface – Social acceptability • Desirability • Do I want this? • Aesthetics • Does it look nice? Does it please my senses? • Branding • Does this product have values that I identify with? • Style • Does this product match my personal sense of style?

  43. Designing an acceptable interface - Practical acceptability • Utility (a.k.a functionality) • Does it do what it is supposed to? • Usability • Can the user get to the functionality? • Accessibility • Can all users get to the functionality? • We will come back to this later…

  44. Where do problems arise? • Focusing on technical development issues • Focusing on deadlines • Not understanding the users • Not focusing on the users Designers designing for themselves (Alan Cooper “The inmates are running the asylum”)

  45. Designers designing for themselves • “I am a user. Why shouldn’t I design for myself?” • “I understand the users. I don’t need to make any special effort to consider them.” • “I don’t have the time/budget/management approval to work with real users.” • “We’ve got user testing scheduled for the final phase of this project.”

  46. Acceptable interfaces? – I

  47. Acceptable interfaces? – II

  48. A better approach to designing for usability…

  49. The fundamental stages of design • STAGE 1 - define the problem • STAGE 2 - develop a solution • STAGE 3 - evaluate the solution user wants/needs system requirements develop a usable system for “all” users verify/validate for all users

  50. cheap • perceived to be easiest • not particularly effective • accessible products • perceived to be expensive/difficult • can be very effective - if done correctly Designing for usability – Reactivity or proactivity? Reactivity - retrospective design consideration Proactivity - designed for usability

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