Development.
Accessibility Analysis.

A study to measure how the website is easy for everyone to use, regardless of their special needs. It could be done by specific tools, following the W3C guideline or even by an usability test.

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Accessibility testingW3C
What is accessibility Testing?Tutorials Point
Myth #5: Accessibility is expensive and difficultUX Myths
Web Accessibility Testingjimthatcher.com