This graphic shows three versions of the same scene. There are three people trying to watch a baseball game from behind the outfield fence. One is tall enough to see over the fence without a riser, the other two are not. The left panel shows all three people standing on the same size riser such that the tall and medium-height people can see over the fence while the shortest of the three still cannot. This frame is labeled "equality". The middle frame shows the tallest person standing on the ground, the medium-height person standing on one riser, and the shortest person standing on two stacked risers. All three people can now see the game. This frame is labeled "equity". The right-most frame shows all three people standing on the ground watching the game. In this frame, the fence has been removed and there are no risers. This frame is labelled "liberation".

In this graphic, the left panel represents inaccessibility; the middle panel represents accommodation; and the right panel represents accessibility.

Accommodation

Accommodation means that some aspect of a system—for example a document or facility—has been adapted or modified to meet the needs of a specific individual or group. Accommodations are patches or fixes, applied retroactively to overcome barriers in the environment or system. In the above graphic, only the tallest person can see over the fence while the other two depend on risers to be able to see over the same fence. In this example, the fence presents a barrier to access, and while the risers represent an accommodation, the fence will continue to present a barrier to others in the future.

Accommodation is not the same as accessibility. Whereas accessible systems are designed to be usable by as many people as possible, regardless of disability or assistive technology, accommodations are reactive, and may not effectively address everyone’s access requirements.

For example, if an instructor distributes a print document in class, a student who is blind will be unable to read that document. In this case, accommodation would require the instructor to provide an alternative version of the document, such as an electronic text or audio file.

Accessibility

On the other hand, accessibility signifies the degree to which products and systems (like electronic and information technology) can be used effectively by people with disabilities. Accessible technology is technology that is designed for use by the greatest number of people, including people with disabilities, and doesn’t require adaptation or modification to remove barriers to access or operation. Conversely, technology that presents barriers to users with disabilities is "inaccessible". In the above graphic, the fence (i.e. the environment) represents a barrier to access. When the barrier is removed, all three people can see the game.

Accessibility is not a discrete feature of a website or application. It is an ongoing aspect of a managed process made up of many intentional design and development decisions, based on real-world practice, institutional policy, public standards, and awareness of the diversity of user experience. It is achieved through designing, developing, purchasing, implementing, and supporting systems that provide an equivalent user experience to all users, regardless of disability or the way they access the technology.

While it is important to understand that there will always be a need for accommodation and remediation in inaccessible systems, concepts of accessibility and inclusive design reflect the social model of disability, in which systemic barriers are minimized for the good of all.