Usability

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Transcript of Usability

  • 1. USABILITY

2. What is Usability? Usability is the measure of the qualityof a users experience wheninteracting with a product or system whether a Web site, a softwareapplication, mobile technology, or anyuser-operated device. 3. What is Usability? Usability is a combination of factors that affect the users experience with the product or system, including: Ease of learning Efficiency of use Memorability Error frequency and severity Subjective satisfaction 4. Why is usability important? Low usability results in: Frustrated users Visitors leaving Reduction in repeat visits Higher support costs Decreased productivity 5. Process Of Flow Of Usability 6. What is Usability Testing? A way to evaluate the interface with real users. Can be done in a lab or in their environment. Can be performed on paper prototypes as well as implemented systems. 7. Types of Usability Problems Product doesnt match job or task Poor organization/layout Unexpected occurrence of events Product not self-evident Requires recall rather than recognition Inconsistent screens, messages,terminology 8. Types of Usability Problems Design is inefficient Cluttered or unattractive design No feedback or poor feedback aboutstatus or errors No exit or undo Help or documentation is not helpful 9. Usability Attributes Attributes should be measurable Example Attributes include Time to complete a task % of task completed Number or % of errors made % of users who like the design No of times user asks for help/gets lost 10. Planning Define the purpose of the Web site Identify target users Get to know your users Define the users tasks Determine scope, usage and change characteristics of the information Define the personality of your site Put together your Web site team 11. Usability Considerations Usability includes considerations suchas: Who are the users, what do theyknow, what can they learn? What do users want or need to do? What is the users generalbackground? What is the users context forworking? What must be left to the machine? 12. Other Considerations Can users easily accomplish intendedtasks at their desired speed? How much training do users need? What documentation or othersupporting materials are available tohelp the user? Can users find solutions in thesematerials? 13. Other Considerations What and how many errors do usersmake when they interact with theproduct? Can the user recover from errors? What do users have to do to recoverfrom errors? 14. Other Considerations Does the product help users recoverfrom errors? For example, does softwarepresent comprehensible, informative,non-threatening error messages? Does the product meet the special needsof disabled users? (Is it accessible?) Are there substantial differencesbetween the cognitive approaches ofvarious users that affect the design, ordoes a one-size-fits-all approach work? 15. Usability Checklist Can visitors read the text, or is abackground color or texture interferingwith the readability? Does the layout of the screenencourage visitors to move their eyefocus in a logical, orderly fashion, orare visitors visually lost? 16. Usability Checklist Is the site designed with a particulartarget audience in mind, or is it trying tobe all things to all people (and thereforenothing to nobody)? Does the order visitors move through apage, or set of pages, match the waythey want to do their work, or do visitorsget lost trying to find information or fill outa form? 17. Usability Checklist Do you know the purpose of the site,or has the site grown appendages thatdont hang together? Have you chosen the best contenttype (text, graphics, audio...) for thematerial and the hardware andsoftware environment of your targetaudience, or is your content presentedinappropriately? 18. Usability Checklist Images & animations: Use the altattribute to describe the function ofeach visual. Image maps: Use the client-side mapand text for hotspots. Multimedia: Provide captioning andtranscripts of audio, and descriptionsof video. 19. Usability Checklist Hypertext links: Use text that makessense when read out of context. Forexample, avoid "click here." Page organization: Use headings,lists, and consistent structure. UseCSS for layout and style wherepossible. Graphs & charts: Summarize or usethe longdesc attribute. 20. Usability Checklist Scripts, applets, & plug-ins - Providealternative content in case activefeatures are inaccessible orunsupported. Frames - Use the noframes elementand meaningful titles. Tables - Make line-by-line readingsensible. Summarize. 21. Links Use Consistent Clickability Colored text (blue) Underlined text Graphic + text Write meaningful labels Users should be able to sense the links destinationfrom its label. Link labels should match the names of theirdestination pages. Link labels should be clearly different from eachother. Links embedded in text should be highly descriptive(9-10 words) and make sense when read out ofcontext. Users ignore surrounding text. 22. Scrolling Eliminate horizontal scrolling Avoid scroll stoppers Use appropriate page lengths: Short pages for homepage, navigation,scanning Longer pages for reading continuous content Stay within 4 screenfuls Use a clickable list of contents on longpages 23. Images Use images that add value Use thumbnails to preview largeimages Place large images below the fold Label images to help usersunderstand them. 24. Summary Have a goal or purpose for your site. Spend time in planning and design. Dont do things because you can, dothem because they add value. Continually evaluate and update yoursite. 25. Conclusion Plan to apply at least one of these techniques to your current and/or next project. Identifying users and their tasks is most important