POUR General Information
There are four main guiding principles of accessibility upon which WCAG has been built. These four principles are known by the acronym POUR.
POUR is a way of approaching web accessibility by breaking it down into four main aspects:
Many of the technology challenges faced by people with disabilities can be described using one of the POUR principles.
Perceivable
Perceivability means the user can identify content and interface elements by means of the senses. For many users, this means perceiving a system primarily visually, while for others, perceivability may be a matter of sound or touch. Information and user interface components must be presentable to users in ways they can perceive.
Perceivable problems:
- An online application form contains numerous input fields. If the field labels are not readable, how can a person successfully complete the application form?
- A chart describes the change in a population over time. If a user cannot see the chart, how can they understand the data?
- An online training video narrates a process for completing a task. If the video is uncaptioned, how can a deaf or hard of hearing user learn from the training how to complete the task?
- An online article is presented as a scanned PDF. If a user cannot read the PDF, how can they learn the content of the article?
- A website’s contact information is displayed in the footer. If the contrast is insufficient to distinguish between background and text, how can a low-vision or color-blind user contact the site owner?
- A kiosk requires users to touch the screen to access an interactive exhibit. If the touch-screen controls are out of reach of the user, how can she interact with the exhibit?
Perceivable Solutions
- Text Alternatives: Provide text alternatives for any non-text content so that it can be changed into other forms people need, such as large print, braille, speech, symbols or simpler language.
- Time-based Media: Provide alternatives for time-based media.
- Adaptable: Create content that can be presented in different ways (for example simpler layout) without losing information or structure.
- Distinguishable: Make it easier for users to see and hear content including separating foreground from background.
Operable
Operability means that a user can successfully use controls, buttons, navigation, and other necessary interactive elements. A user can successfully use assistive technology like voice recognition, keyboards, screen readers etc.
Operable Problems
- Mouse-dependent web content will be inaccessible to a person cannot use a standard mouse. A navigation menu reveals a submenu of links when a user hovers over it with a mouse. If the menu doesn’t expand when it receives focus, how can a keyboard user access the submenu?
- A website’s social media links can be activated with a click of the mouse. If the links don’t receive keyboard focus, how can a keyboard user follow the links to social media?
- People with low or no vision also relay on the functionality of the keyboard. They may be able to manipulate a mouse just fine, but it doesn’t do them much good because they can’t see where to click on the screen. The keyboard is much easier for a person who is blind to manipulate.
- An online form permits a user to make multiple selections from a drop-down menu. If the user cannot simultaneously press a Control key and click on the menu, how can she make multiple selections?
Operable Solutions
- Keyboard Accessible: Make all functionality available from a keyboard. Keyboard accessibility is one of the most important principles of Web accessibility because it cuts across disability types and technologies
- Enough Time: Provide users enough time to read and use content.
- Seizures: Do not design content in a way that is known to cause seizures.
- Navigable: Provide ways to help users navigate, find content, and determine where they are.
Understandable
Understandable technology is consistent in its presentation and format, predictable in its design and usage patterns, and appropriate to the audience in its voice and tone. Users should be able to comprehend the content, and learn and remember how to use the interface.
Understandable Problems
- A website’s navigation consists of a number of links that are displayed in a different order from page to page. If a user has to relearn basic navigation for each page, how can she effectively move through the website?
- A PDF registration form contains required email and phone number fields. If the form doesn’t inform the user when there is an input error, how can the user understand why the form cannot be submitted?
- A Word document contains a number of non-English words and phrases. If the languages are not indicated, how can assistive technology present the text correctly?
- A technical website makes use of numerous abbreviations, acronyms, and jargon. If these are never defined, how can users with disabilities (and others) understand the content?
Understandable Solutions
- Readable: Make text content readable and understandable.
- Predictable: Make Web pages appear and operate in predictable ways.
- Input Assistance: Help users avoid and correct mistakes.
Robust
Content must be robust enough that it can be interpreted reliably by a wide variety of users, allowing them to choose the technology they use to interact with websites, online documents, multimedia, and other information formats.
Robust Problems
- A website requires a specific version of a web browser to make use of its features. If a user doesn’t or can’t use that browser, how can that user experience the features of the site?
- A document format is inaccessible to a screen reader on a particular operating system. If a user employs that OS for day-to-day tasks, how can she gain access to the document?
Robust Solutions
- Compatible: Maximize compatibility with current and future user tools, including assistive technologies.
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