Accessibility is the concept of whether a product or service can be used by everyone. Accessibility laws exist to aid people with disabilities, but designers should strive to include all possible users in many contexts of use. Doing so has powerful benefits, resulting in distinctly better designs for all.
Accessibility is sometimes confused with usability. Both overlap and are important parts of User Experience Design (UXD), but there are some key differences. Usability is concerned with effectiveness, efficiency, and satisfaction when using a product. This includes accessibility since an inaccessible product is unusable to persons with disabilities. Accessibility is concerned with whether all users can access a comparable user experience, regardless of how they interact with a product or service.
Accessibility brings benefits to all users; it's not just the right thing to do. Accessibility features that aid users with disabilities almost always help other users, too.
A great example of this is subtitles; they help people with hearing difficulties and also help a user who would like to watch the video on mute. The clear, high-contrast text helps users with vision difficulties, but also helps users, as we have all experienced, in bright sunlight.
Regardless of abilities, many users will face challenges with demanding contexts. Designing for all ability levels enables us to create products and services that anyone can use.
You should always analyze the number and types of potential accessibility issues users may have, including those with impaired vision, motor difficulties, cognitive impairments or learning disabilities, and deafness or impaired hearing. Ability barriers can also arise for any user, such as those due to incidental (e.g., sleep-deprivation) or environmental (e.g., using a mobile device underground) circumstances. The possibilities are practically limitless concerning who might be trying to access your product/service.
See some revealing insights on accessibility, including examples: https://uxplanet.org/a-primer-to-web-accessibility-for-designers-2c548448c612
Here’s a helpful resource featuring examples of accessible design: https://medium.com/tealmedia/designing-for-accessibility-the-ultimate-in-ux-e366165d0db7
Learn how to design with accessibility in mind with our course addressing accessibility: https://www.interaction-design.org/courses/accessibility-how-to-design-for-all
What is Accessibility?: https://www.interaction-design.org/literature/topics/accessibility