Usability Guidelines

Acknowledgments:Gerry Gaffney, Jakob Nielsen, Larry Constantine, Jared Spool

The guidelines below include most factors to consider during a usability evaluation of a web site. Not all factors apply to every site.

For a much more extensive set of guidelines, we recommend Research-Based Web Design & Usability Guidelines created for the National Cancer Institute. This is an excellent resource for usability practitioners and designers and developers.

View/print selected guidelines (PDF)

Navigation

• Current location within the site is shown clearly
• Link to the site's main page is clearly identified
• Major/important parts of the site are directly accessible from the main page
• Site map is provided for a large, complex site.
• Easy to use Search function is provided, as needed.

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Functionality

• Site accommodates novice to expert users.
• Functions are clearly labeled 
• Essential functions are available without leaving the site. 
• Plug-ins are used only if they add value.

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User control

• Site reflects user's workflow
• User can cancel any operation
• Clear exit point is provided on every page
• Per-page size is less than 50K, to accommodate slow connections
• All appropriate browsers are supported

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Language and content

• Important information and tasks are given prominence
• Information of low relevance or rarely used information is not included
• Related information or tasks are grouped:
  • on the same page or menu
  • in the same area within a page
• Language is simple, without jargon
• Paragraphs are brief
• Links are concise, expressive, and visible--not buried in text
• Terms are defined

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Online help and user guides

• Site is designed to require minimal help and instructions
• Help and instructions, if needed, are easily accessible

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System and user feedback

• It is always clear what is happening on the site -- visual hints, etc.
• Users can receive email feedback if necessary
• Users can give feedback via email or a feedback form
• Confirmation screen is provided for form submittal
• All system feedback is timely
• Users are informed if a plug-in or browser version is required
• Each page includes a "last updated" date

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Web accessibility

Tools, checklist, and guidelines at: www.w3.org/TR/WAI-WEBCONTENT

• Site follows current web standards. See HTML 4.0, Cascading Style Sheets (CSS1)
  Cascading Style Sheets are used for layout and style where possible
• Images and animations . The attribute ALT= is used for images, animations, and other objects
• Image maps . Site uses client-side map and text for hotspots 
• Multimedia. Site provides captioning and transcripts of audio; and descriptions of video
• Web versions of PDF documents are provided
• Link labels makes sense when read out of context; site avoids link names such as "click here"
• Page organization is accomplished with headings, lists, and consistent structure
• Graphs and charts. Summaries are provided for graphs and charts, or the LONGDESC attribute is used 
• Scripts, applets, & plug-ins. Alternative content is provided for scripts, applets, and plug-ins in case these active features are inaccessible or unsupported
• Frames. For frames pages, site includes the NOFRAMES option and meaningful titles 
• Tables. Line-by-line reading of tables is sensible, and summaries are included where possible
• Validation. Site has been validated using the W3C's HTML Validation Service and the Bobby Accessibility Checker
• Site has been tested on a variety of platforms (Windows, Mac, Linux, Unix) and browsers (Netscape 6, 7; IE 5, 6; lynx) 

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Consistency

• The same word or phrase is used consistently to describe an item
• Link reflects the title of the page to which it refers
• Browser page title is meaningful and reflects main page heading

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Error prevention and correction

• Users can rely on recognition, not memory, for successful use of the site
• Site tolerates a reasonable variety of user actions
• Site provides concise instructions for user actions, including entry format
• Error messages are visible, not hidden
• Error messages are in plain language
• Error messages describe actions to remedy a problem
• Error messages provide a clear exit point
• Error messages provide contact details for assistance

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Architectural and visual clarity

• Site is organized from the user's perspective
• Site is easily scannable for organization and meaning
• Site design and layout is straightforward and concise
• Site design and layout are redundant only when required for user productivity
• White space is sufficient; pages are not too dense
• Unnecessary animation is avoided
• Colors used for visited and unvisited links are easily seen and understood
• Bold and italic text is used sparingly

Send questions, comments, and suggestions to usability-team@mit.edu

Usability @ MIT

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