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Usability
Usability, simply put, is the degree to which designed products (including documents and websites) successfully meet the needs of the people using them. Usability testing for the Web is an iterative process of testing sites before, during, and after design. Tests include expert heuristic evaluations, user tests, and product tests for functionality of the site. Regardless of the specific testing methods you implement, the people who will eventually use the site, and their purposes and contexts for that use, should be at the focus of development and testing. Usability efforts should focus on the integration of function and presentation.
In testing the document, the team elicit feedback from test participants representative of various user groups. Choices of testing procedures and participants should reflect concern for
- how the people actually use the site,
- how users think about the site and
- affective issues (what is the user's attitude toward the documents); and
- performance and behavior issues (what do users actually do with the product, how do they try to solve problems, what do they do when faced with a problem).
Usability Factors in Brief
Usefulness of the product - The product enables a user to do his work and achieve his goals.
Learnability - How rapidly a user can become productive. A measure of how rapidly an infrequent user can re-learn the product after periods of not using it.
Memorability – The degree to which a system is easy to remember from use-to-use. People may use some applications or website sporadically. When a system or website is easy to remember, people will be able to be productive more quickly each time they encounter it.
Effectiveness - The measure of user productivity and how well a user can perform his/her job.
Efficiency - The measure of how quickly a user can perform work and the error rate in doing so. Minimizes chance for user errors. Undo/Re-Do, Esc, Short-Cuts available.
Error rate – The measure of errors that users make when using a system, and the degree to which the system allows users to recover from errors.
Satisfaction (Attitude) - The degree to which users like the product. Measurement of attitude, perceptions, and feelings about the product.
Website Usability Guidelines
Jacob Nielsen, an expert on web usability, has developed a list of guidelines for accessible web sites. Use these guidelines as you plan, design, and test your site. The usability of websites is increased by incorporating these elements:
- Include easy-to-locate identifiers on each page so readers are less likely to lose their place
- Provide clear transitions from one page to the next, which may include simple links, pop-up windows, zooming
- Ensure a short downloading time . . . the longer it takes, the less happy users will be
- Make sure the site works well on different browsers and platforms (PC, Mac, etc.)
- Design for multiple audiences. Your content should support the widest possible audience. Users come from from different places, speak and read different languages, and expect different things. Avoid technical jargon, colloquial language, or complex metaphors when designing and writing for the web
- Design for user control and choice. People should be able to use their browser's tools to view and navigate pages as they wish. Users should be able to disable graphics and still navigate your site (which means providing inforamtion and navigation that doesn't rely exclusively on graphics). Size tables using percentages rather than absolute sizes in pixels so people can resize window when possible. Use percentages rather than absolute sizes in pixels or points to control font size so that users can increase or decrease the font size in their browsers.
- Make pages at your site easy to bookmark by keeping them in the same location, keeping consistent file names, and avoiding frames whenever possible.
- Provide a link to your home page on every page of your site so that users can always get back to the top level of your site.
- Minimize repeating animation, scrolling text, embedded sound files, and other active features that the user cannot turn off.
- Provide help for users when necessary.
- TEST the usability of your site!