Usability, Accessibility, and Design Evaluation


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Usability, Accessibility, and Design Evaluation

  1. 1. Damian Gordon
  2. 2. The Design of Everyday Things by Donald Norman “The human mind is exquisitely tailored to make sense of the world. Give it the slightest clue and off it goes, providing explanation, rationalization, understanding. Consider the objects – nooks, radios, kitchen, appliances, office machines, and light switches – that make up our everyday lives. Well- designed objects are easy to interpret and understand. They contain visible clues to their operation. Poorly designed objects can be difficult and frustrating to use. They provide no clues – or sometimes false clues. They trap the user and thwart the normal processing interpretation and understanding…The result is a world filled with frustration.”
  3. 3.    A key issue is usability. Usability is the ease of use and learnability of a human-made object. The object of use can be a software application, website, book, tool, machine, pro cess, or anything a human interacts with.
  4. 4.   A usability study may be conducted as a primary job function by a usability analyst or as a secondary job function by designers, technical writers, marketing personnel, and others. It is widely used in consumer electronics, communication, and knowledge transfer objects (such as a cookbook, a document or online help) and mechanical objects such as a door handle or a hammer.
  5. 5.   Usability includes methods of measuring usability and the study of the principles behind an object's perceived efficiency or elegance. In human-computer interaction and computer science, usability studies the elegance and clarity with which the interaction with a computer program or a web site (web usability) is designed.
  6. 6.     Born 5 Oct 1957 Born in Copenhagen, Denmark a leading web usability consultant founded the "discount usability engineering" movement for fast and cheap improvements of user interfaces and has invented several usability methods.
  7. 7.     Born 5 Oct 1957 Born in Copenhagen, Denmark a leading web usability consultant founded the "discount usability engineering" movement for fast and cheap improvements of user interfaces and has invented several usability methods.
  8. 8.  This dominant reading pattern looks somewhat like an F and has the following three components:
  9. 9.  Users first read in a horizontal movement, usually across the upper part of the content area. This initial element forms the F's top bar.
  10. 10.  Next, users move down the page a bit and then read across in a second horizontal movement that typically covers a shorter area than the previous movement. This additional element forms the F's lower bar.
  11. 11.  Finally, users scan the content's left side in a vertical movement. Sometimes this is a fairly slow and systematic scan that appears as a solid stripe on an eyetracking heatmap. Other times users move faster, creating a spottier heatmap. This last element forms the F's stem.
  12. 12.    Users won't read your text thoroughly in a word-by-word manner. Exhaustive reading is rare, especially when prospective customers are conducting their initial research to compile a shortlist of vendors. Yes, some people will read more, but most won't. The first two paragraphs must state the most important information. There's some hope that users will actually read this material, though they'll probably read more of the first paragraph than the second. Start subheads, paragraphs, and bullet points with information-carrying words that users will notice when scanning down the left side of your content in the final stem of their F-behavior. They'll read the third word on a line much less often than the first two words.
  13. 13. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Visibility of system status Match between system and the real world User control and freedom Consistency and standards Error prevention Recognition rather than recall Flexibility and efficiency of use Aesthetic and minimalist design Help users recognize, diagnose, and recover from errors Help and documentation 15
  14. 14. 1. Visibility of system status  The system should always keep users informed about what is going on, through appropriate feedback within reasonable time. 16
  15. 15. 2. Match between system and the real world  The system should speak the users' language, with words, phrases and concepts familiar to the user, rather than system-oriented terms. Follow real-world conventions, making information appear in a natural and logical order. 17
  16. 16. 3. User control and freedom  Users often choose system functions by mistake and will need a clearly marked "emergency exit" to leave the unwanted state without having to go through an extended dialogue. Support undo and redo. 18
  17. 17. 4. Consistency and standards  Users should not have to wonder whether different words, situations, or actions mean the same thing. Follow platform conventions. 19
  18. 18. 5. Error prevention  Even better than good error messages is a careful design which prevents a problem from occurring in the first place. Either eliminate error-prone conditions or check for them and present users with a confirmation option before they commit to the action. 20
  19. 19. 6. Recognition rather than recall Minimize the user's memory load by making objects, actions, and options visible. The user should not have to remember information from one part of the dialogue to another. Instructions for use of the system should be visible or easily retrievable whenever appropriate. 21
  20. 20. 7. Flexibility and efficiency of use  Accelerators -- unseen by the novice user -may often speed up the interaction for the expert user such that the system can cater to both inexperienced and experienced users. Allow users to tailor frequent actions. 22
  21. 21. 8. Aesthetic and minimalist design  Dialogues should not contain information which is irrelevant or rarely needed. Every extra unit of information in a dialogue competes with the relevant units of information and diminishes their relative visibility. 23
  22. 22. 9. Help users recognize, diagnose, and recover from errors  Error messages should be expressed in plain language (no codes), precisely indicate the problem, and constructively suggest a solution. 24
  23. 23. 10. Help and documentation Even though it is better if the system can be used without documentation, it may be necessary to provide help and documentation. Any such information should be easy to search, focused on the user's task, list concrete steps to be carried out, and not be too large. 25
  24. 24. 1. 2. 3. 4. 5. 6. 7. Equitable Use Flexibility in Use Simple and Intuitive Perceptible Information Tolerance for Error Low Physical Effort Size and Space for Approach and Use 27
  25. 25. • • • • Provide the same means of use for all users: identical whenever possible; equivalent when not Avoid segregating or stigmatising any users Provisions for privacy, security and safety should be equally available to all users Make the design appealing to all users 28
  26. 26. 29
  27. 27. • • • • Provide choice in method of use Accommodate right-handed or left-handed access and use Facilitate the user’s accuracy and precision Provide adaptability to the user’s pace 30
  28. 28. 31
  29. 29. • • • • • Eliminate unnecessary complexity Be consistent with user expectations and intuition Accommodate a wide range of literacy and language skills Arrange information consistent with its importance Provide effective prompting and feedback during and after task completion 32
  30. 30. 33
  31. 31. • • • • • Use different modes (pictorial, verbal, tactile) for redundant presentation of essential information Provide adequate contrast between essential information and its surroundings Maximise legibility of essential information and its surroundings Differentiate elements in ways that can be described (i.e. make it easy to give instructions or directions) Provide compatibility with a variety of techniques or devices used by people with sensory limitations 34
  32. 32. 35
  33. 33. • • • • Arrange elements to minimise hazards and errors: most used elements, most accessible; hazardous elements eliminated, isolated or shielded Provide warnings of hazards and errors Provide fail safe features Discourage unconscious action in tasks that require vigilance 36
  34. 34. 37
  35. 35. • • • • Allow user to maintain a neutral body position Use reasonable operating forces Minimise repetitive actions Minimise sustained physical effort 38
  36. 36. 39
  37. 37. • • • • Provide a clear line of sight to important elements for any seated or standing user Make reach to all components comfortable for any seated or standing user Accommodate variations in hand and grip size Provide adequate space for the use of assistive devices or personal assistance 40
  38. 38. 41
  39. 39. 1. 2. 3. 4. 5. 6. 7. 8. Strive for consistency Cater to universal usability Offer informative feedback Design dialogs to yield closure Prevent errors Permit easy reversal of actions Support internal locus of control Reduce short term memory 42
  40. 40. Perceptual Principles 1. Make displays legible (or audible) 2. Avoid absolute judgment limits 3. Top-down processing 4. Redundancy gain 5. Similarity causes confusion: Use discriminable elements Mental Model Principles 6. Principle of pictorial realism 7. Principle of the moving part Principles Based on Attention 8. Minimizing information access cost 9. Proximity compatibility principle 10. Principle of multiple resources Memory Principles 11. Replace memory with visual information: knowledge in the world 12. Principle of predictive aiding 13. Principle of consistency
  41. 41. 1 2 3 4 5 6 7 8 Anticipation Autonomy Colour Blindness Consistency Defaults Efficiency of the User Explorable Interfaces Fitts' Law 9 Human-Interface Objects 10 Latency Reduction 11 Learnability 12 Metaphors 13 Protect the User's Work 14 Readability 15 Track State 16 Visible Interfaces
  42. 42. Managing the Thinking Setting the focus Making summaries Overviews & conclusions Action Plans Information & Data Feelings and Intuition Neutral and objective Checked and believed facts Missing information & Where to source it Emotions and hunches No reasons or justifications “At this point” Keep it short FOCUS Creative Thinking Possibilities * Alternatives New Ideas * New Thinking Overcome black hat issues Reinforce yellow hat issues Why it may work Values * Benefits (both known and potential) Logical reasons must be given Why it may not work Cautions * Dangers Problems * Faults Logical reasons must be given
  43. 43. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Creative Design Aesthetic Design Sustainable Design Consistent Design Understandable Design Unobtrusive Design Useful Design Minimalist Design Thorough design Honest Design