People affected by accessibility

Basically this is everyone - not just people with disabilities.

Accessibility helps the maximum number of people to browse and act upon your information. It may be because they choose to use different ways of accessing your content, or they may be forced to adopt certain methods due to disability, or circumstance.

different types of device: small screen laptop, tablet, pda

Everyone does not use a PC with large monitor and Internet Explorer!

Disabilities that affect web access

Many different kinds of disability can affect access to the Web. Listed below are some examples and what some people with these disabilities do in order to facilitate their web browsing.

Visual disabilities
- Blindness - people often use a screen reader program to change visual information into speech and sound.
- Low vision - people often change text size, background and foreground colours, or use software that magnifies portions of the screen, some in addition use screen readers.
- Colour blindness - some people change background and foreground colours to improve their vision of information.
Hearing disabilities
- Deafness - despite the limited amount of auditory information on the Internet (and NICS Web sites in particular) many people who are deaf have sign language as their first language and can therefore experience difficulty with written content.
- Hard of hearing - for these people (as well as those who are profoundly deaf) features such as captions and transcripts assist their access to some types of information.
Physical disabilities
- Motor disabilities - people may rely on the keyboard or some other alternative input device (e.g. head-mouse, voice recognition software) to navigate and input information.
Cognitive and neurological difficulties/disabilities
- Dyslexia, dyscalculia - some people aid their reading by changing font, colour combinations and line height and width. Some may rely on using several senses at a time e.g. augment the written word with speech synthesis.
- Attention deficit disorder - people may need to turn off animations or other distracting information.
- Epilepsy and seizure disorders - people may need to turn off animations, blinking or certain types of audio information.
- Other disorders - e.g. spatial neglect, agnosias, memory loss - a wide variety of coping strategies are employed.
Age related conditions - a wide variety of strategies are used.

Please note this is not meant to be a comprehensive list, and the terminology/classification used is that commonly found when web accessibility is discussed amongst web professionals. It should also be noted that abilities vary from person to person, and over time, also people often have combinations of different disabilities, and combinations of varying levels of severity.

Different ways of accessing content

Not everyone uses the same software or the same type of computer to access the Internet. There are hundreds of different browser programs and many different operating systems and types of computer and monitors. Some people change what they use, or have different needs according to where they are or what they are doing, e.g.

Outside on a bright sunny day - may use a screen reader as cannot see screen, or may need to increase contrast between foreground and background
In a noisy environment - may require captions and/or transcripts
Walking around - small screen (pda, phone, etc.) perhaps text only
Driving in a car - hands busy, eyes busy therefore use technology similar to screen reader software used by blind people

Summary

You should aim for maximum accessibility because you cannot predict the needs or preferences of your potential audience.