Accessibility is about making sure your service can be used by as many people as possible.
Thinking about this from the beginning will help you:
- make sure that nobody is excluded
- find out earlier if any parts of your service aren’t accessible - problems usually cost less to fix if you find them early.
But the concept of accessibility doesn’t just apply to people with disabilities - all users will have different needs at different times and in different circumstances Someone’s ability to use a service could be affected by their:
- location - they could be in a noisy cafe, sunny park or area with slow wifi
- health - they may be tired, recovering from an accident or have a broken arm
- equipment - they could be on a mobile phone or using an older browser
The Four Principles
To complete a task on a website there are a number of things that need to work.
The information that the user needs must be perceivable to them, it should be available to one of their senses (sight, hearing or touch). As an example, if the information is provided as text, someone that has sight needs to be able to see it. If someone has no sight the text needs to be available in a format that means a screen reader can convert it to audio and an electronic braille device can convert it to touch.
The information that the user needs must be understandable to them. That is, the information makes sense to them. For people that struggle to process text, which may be the case for someone that has dyslexia or is on the autistic spectrum, the information should be in plain english and aid comprehension.
The web page needs to be operable. That is, if someone is using a keyboard for example, they can still do everything that someone using a mouse can do. This includes being able to navigate the website, use forms to provide information and use controls such as buttons.
The web page needs to be robust. That means that the web page works as expected in the technology that someone is using such as a screen reader.