Checklist: Heuristic Principles for Usability 1
A heuristic evaluation is an expert review of a user interface with reference to explicit principles termed "heuristics." During the evaluation, reviewers see how well the website application fulfills the basic requirements for usability or accessibility.
To conduct an heuristic evaluation of a website or application, travel through the pages of the site, reflecting on each of the listed principles, and recording compliance and violations. The heuristic principles should also be kept in mind during cognitive walkthroughs (see Right column).
___ Visibility of system status
The system should always keep users informed about what is going on, through appropriate feedback within reasonable time.
___ Match between system and the real world
The system should speak the user's language, with words, phrases and concepts familiar to the user, rather than system-oriented terms. Follow real-world conventions, making information appear in a natural and logical order.
___ User control and freedom
Users often choose system functions by mistake and will need a clearly marked "emergency exit" to leave the unwanted state without having to go through an extended dialogue. Support undo and redo.
___ Consistency and standards
Users should not have to wonder whether different words, situations, or actions mean the same thing. Follow platform conventions.
___ Error prevention
Even better than good error messages is a careful design which prevents a problem from occurring in the first place. Either eliminate error-prone conditions or check for them and present users with a confirmation option before they commit to the action.
___ Recognition rather than recall
Minimize the user's memory load by making objects, actions, and options visible. The user should not have to remember information from one part of the dialogue to another. Instructions for use of the system should be visible or easily retrievable whenever appropriate.
___ Flexibility and efficiency of use
Accelerators - unseen by the novice user - may often speed up the interaction for the expert user such that the system can cater to both inexperienced and experienced users. Allow users to tailor frequent actions.
___ Aesthetic and minimalist design
Dialogues should not contain information which is irrelevant or rarely needed. Every extra unit of information in a dialogue competes with the relevant units of information and diminishes their relative visibility.
___ Help users recognize, diagnose, and recover from errors
Error messages should be expressed in plain language (no codes), precisely indicate the problem, and constructively suggest a solution.
___ Help and documentation
Even though it is better if the system can be used without documentation, it may be necessary to provide help and documentation. Any such information should be easy to search, focused on the user's task, list concrete steps to be carried out, and not be too large.
Checklist: Heuristic Principles for Accessibility
The following is an abridged version of the Simple Accessibility Walkthrough Protocol - see this document for a better understanding how these principles apply to accessibility.
___ Assess the overall layout, structure and content of the page
- Is the page structured into logical sections?
- Are those sections clearly labeled, and is their function apparent?
- Do paragraphs, sections, and tables have meaningful headings?
- Is the information in forms grouped in relevant "clumps"?
- Is site content helpful to users of assistive technology?
- Can headings, captions and links be understood independently of their surrounding context?
- Does sentence structure follow writing conventions in a consistent way?
- Are there sufficient non-visual cues to convey the overall structure? (I.e., Are there sufficient text and/or explanations on the page to understand its purpose and functionality without relying on graphic elements).
- Are there sufficient visual cues to support page content?
- Are visual cues recognizable without being differentiated by color?
- Does there seem to be sufficient contrast between foreground (text) and background colors?
- Are the most important information and navigational elements prioritized high on the page?
- Is navigation consistent from page to page? Is the structure of content consistent from page to page?
___ Play around with the layout: enlarge the font size; change the size of the window (bigger and smaller); adjust your resolution
- Is all the text still visible? Does it overlap?
- Does visual context break down at large text sizes?
- Are headers, labels, and visual cues still correctly associated with their content?
- Do columns shift or realign correctly?
___ Use the Tab key to navigate through the entire page.
- Do all links and controls receive focus as you tab through the page?
- Can all controls be activated with the Enter or Space keys?
- Is movement possible using arrow keys within the object (for example, to move around cells within a table, or within a form)?
- Does tabbing follow a logical sequence through the page?
- Is content easily accessible and not secondary to navigational "chrome"? Are navigation and content formats consistent from page to page?
- Are there any areas where you get stuck and have to use the mouse?
- Are shortcuts or skip links provided to make keyboard access quicker? Are they visible and clear?
___ Use Internet Explorer (6 or 7) or Firefox with Popup Alt Attributes Extension to check for alternative text for all images and title text for links.
- Do images have text alternatives for visual content?
- Are descriptions short (around 20 characters maximum) and using the
- Are decorative or meaningless images such as spacer graphics using empty alt text (alt="") so they will be ignored by screen readers?
- If a description cannot be adequately provided with 20 characters, does a graphic have a supplemental
- Is title text specified for links? When link text cannot be made descriptive enough by itself, more of an explanation can be provided through the use of the
1 The above section lists the original Nielsen and Molich heuristics, as refined by Nielsen.