270 likes | 679 Vues
User Interface Design Principles and Usability Testing. HCI. User Interface Design. If screens are confusing or product is difficult to use software product will not be used!. Which one do you prefer?. Guidelines for User-Friendly Interfaces.
E N D
User Interface Design If screens are confusing or product is difficult to use software product will not be used!
Guidelines for User-Friendly Interfaces • Instructions that are easy to learn and remember • Context sensitive help • Different help texts should be displayed based on the current state of application • Logically connected functions presented together and consistently • File menu: print, save, open, new • Create graphical user interfaces whenever possible • graphical symbols trigger faster recognition than do textual input and output
Know the User of your Application • Novice user who has rarely used a computer • Require lots of feedback and very clear, constructive error messages • Limit number of commands required • Knowledgeable user who has used a variety of systems • Allow ability to explore without doing something dangerous. • Menus, consistent commands, help screens • Frequent user • Many shortcuts
Clippy • Why was Clippy dislikedby so many? • Was it annoying, distracting,patronising or other? • What sort of user liked Clippy?
User frustration • Many causes: • When an application doesn’t work properly or crashes • When a system doesn’t do what the user wants it to do • When a user’s expectations are not met • When a system does not provide sufficient information to enable the user to know what to do • When error messages pop up that are vague, obtuse or condemning • When the appearance of an interface is garish, noisy, gimmicky or patronizing • When a system requires users to carry out too many steps to perform a task, only to discover a mistake was made earlier and they need to start all over again
Know the User of Your Application • Gather user population profiles that reflect: • age • gender • physical ability • training • goals • personality • Understand the future users of the system
Rules for Interface Design • Be consistent in syntax, terminology, action sequences and layout. • Do not allow user to delete a character, remove a word, destroy a line and kill a paragraph. • All menus should follow the same format • All error messages should use similar terminology and appear in the same location
Rules for Interface Design • Provide Shortcuts • abbreviations, special keys, hidden commands • File/Edit/Cut, scissors icon, CTRL-X • Offer Useful, Meaningful Feedback • Every action, successful or unsuccessful, should result in some sort of feedback to the user • audio tone, display of some text, change of icon • Verify Deletion Tasks • Do not delete any major item without asking the user whether he is sure about the deletion
Rules for Interface Design • Allow Easy Reversal of most actions • An “undo” command increases user productivity by allowing the user to reverse the most recent actions without having to start the entire operation over again in case of mistakes. • relieves user anxiety • Display Only Currently Relevant Information • The user should not have to wade through extra information to find what is needed • Context sensitive help
Discussion: Your standards • Uniformity of appearance reduces learning time • What are your standards? • Size of letters, CAPITALIZATION, Color, Line length, Number of lines on screen • Who are your users? How will your interface address their needs? • What shortcuts will you provide for the advanced user? • What context sensitive help will you provide? • How does your design allow for easy reversal of operations?
Usability Testing • The process by which the human-computer interaction characteristics of a system are measured, and weaknesses are identified for correction. • Usability -the degree to which software assists the user to accomplish a task, as opposed to becoming an additional impediment to such accomplishment.
Usability goals • Easy to learn • Navigation • Subjective user satisfaction • Effective to Use • Efficient to Use • Have good utility • Easy to remember how to use • General appearance
Sample Questions 1 Demographic Questionnaire -http://wiki.fluidproject.org/display/fluid/Layout+Customizer+User+Testing+-+Round+1+Demographic+Questionnaire • What is your gender? • What is your age? • What is your role on campus? • Computer Skill level -- Are you comfortable using the computer
Sample Questions 2 Two Simple Post-Test Questions - http://www.uie.com/brainsparks/2006/03/23/two-simple-post-test-questions/ • What are two things about the design that you really liked? • What are two things about the design that you didn’t like?
Sample Questions 3 • The software is easy to use. • I can easily get back to a previous page. • I always know where I am on the site. • It’s easy to get lost. • The software colors appeal to me. • The design of the software appeals to me. • The text is easy to read. • I would consider buying this software
Sample Questions 4 http://ldt.stanford.edu/~jeepark/jeepark+portfolio/mastersproject/usertest2.htm • I understand how to use the interface. • I can make the right choice and explain the why�s. • I learned something new. • I found the experience potentially helpful for me • I found the experience interesting and engaging.
Sample Questions 5 What emotions were provoked when using the software? I found this software: • enjoyable • entertaining • helpful • challenging • aesthetically pleasing • boring • annoying •frustrating • cutsey
Sample Questions 6 http://www.programmingtalk.com/showthread.php?t=45103 • I found the software easy to navigate: 1 2 3 4 5 • I found the software to be readable: 1 2 3 4 5 • I believe the software displayed correctly for me: 1 2 3 4 5 • I thought the software loaded quickly: 1 2 3 4 5 • I think the software is visually appealing: 1 2 3 4 5 • What features could be improved on the software? • What features did you like? • What parts of the software didn't you like? • Any other comments?
An Interactive Heuristic Evaluation Toolkit • This interactivity teaches you about how to choose appropriate heuristics for different user-groups with different types of devices • - http://www.id-book.com/catherb/index.htm
Designing and Using Questionnaires • - This interactivity allows you to select from among 8 questionnaire templates. You can use the templates as they are or customize them for own studies. • http://www.id-book.com/interactive_perlman.htm