What is Usability? Usability is the measure of the quality of a users experience when interacting with a product or system — whether a Web site, a software application, mobile technology, or any user-operated device.
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
Why is usability important? Low usability results in: ◦ Frustrated users ◦ Visitors leaving ◦ Reduction in repeat visits ◦ Higher support costs ◦ Decreased productivity
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.
Types of Usability Problems Product doesn‟t match job or task Poor organization/layout Unexpected occurrence of events Product not self-evident Requires recall rather than recognition Inconsistent screens, messages, terminology
Types of Usability Problems Design is inefficient Cluttered or unattractive design No feedback or poor feedback about status or errors No exit or undo Help or documentation is not helpful
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
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
Usability Considerations Usability includes considerations such as: Who are the users, what do they know, what can they learn? What do users want or need to do? What is the users general background? What is the users context for working? What must be left to the machine?
Other Considerations Can users easily accomplish intended tasks at their desired speed? How much training do users need? What documentation or other supporting materials are available to help the user? Can users find solutions in these materials?
Other Considerations What and how many errors do users make when they interact with the product? Can the user recover from errors? What do users have to do to recover from errors?
Other Considerations Does the product help users recover from errors? For example, does software present comprehensible, informative, non-threatening error messages? Does the product meet the special needs of disabled users? (Is it accessible?) Are there substantial differences between the cognitive approaches of various users that affect the design, or does a one-size-fits-all approach work?
Usability Checklist Can visitors read the text, or is a background color or texture interfering with the readability? Does the layout of the screen encourage visitors to move their eye focus in a logical, orderly fashion, or are visitors visually lost?
Usability Checklist Is the site designed with a particular target audience in mind, or is it trying to be all things to all people (and therefore nothing to nobody)? Does the order visitors move through a page, or set of pages, match the way they want to do their work, or do visitors get lost trying to find information or fill out a form?
Usability Checklist Do you know the purpose of the site, or has the site grown appendages that dont hang together? Have you chosen the best content type (text, graphics, audio...) for the material and the hardware and software environment of your target audience, or is your content presented inappropriately?
Usability Checklist Images & animations: Use the alt attribute to describe the function of each visual. Image maps: Use the client-side map and text for hotspots. Multimedia: Provide captioning and transcripts of audio, and descriptions of video.
Usability Checklist Hypertext links: Use text that makes sense when read out of context. For example, avoid "click here." Page organization: Use headings, lists, and consistent structure. Use CSS for layout and style where possible. Graphs & charts: Summarize or use the longdesc attribute.
Usability Checklist Scripts, applets, & plug-ins - Provide alternative content in case active features are inaccessible or unsupported. Frames - Use the noframes element and meaningful titles. Tables - Make line-by-line reading sensible. Summarize.
Links Use Consistent Clickability ◦ Colored text (blue) ◦ Underlined text ◦ Graphic + text Write meaningful labels ◦ Users should be able to sense the link‟s destination from its label. ◦ Link labels should match the names of their destination pages. ◦ Link labels should be clearly different from each other. ◦ Links embedded in text should be highly descriptive (9-10 words) and make sense when read out of context. Users ignore surrounding text.
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 long pages
Images Use images that add value Use thumbnails to preview large images Place large images „below the fold‟ Label images to help users understand them.
Summary Have a goal or purpose for your site. Spend time in planning and design. Don‟t do things because you can, do them because they add value. Continually evaluate and update your site.
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