Adam Silver’s Post

Usability is about designing things that are intuitive and easy to use. Accessibility is about making things which remove barriers for people with any kind of impairment or disability. We’ve all seen things which are considered usable (for most people) yet not accessible because parts of it don’t work with a keyboard, for example. But I’ve also seen examples where they’re fully accessible, as in complaint with WCAG AA, yet they’re not usable. Technically everything works on assistive technology etc, but the language in the product is so complex and full of acronyms and Latin phrases that most users can’t understand it. There’s a lot of overlap, but accessibility is more about making sure the good usability translates for people with disabilities or impairments to create an equal level of usability for everybody.

I'll add that while some additional skills are needed to make accessible products and services, both work when user centred design - as a process, with the right level of research and testing at the right points - is followed. Which is why I'll always start thinking about inclusive design at the earliest stages, not waiting for an audit to tell me what to fix in Beta. Also that there's a hefty proposition and usability component to accessibility that sits outside WCAG, Section 508 and any other standards (software, browers etc). I'll always remember Tesco's product owner (equivalent) telling a large audience back in 2005 how they made a properly WCAG 1.0 AA website they thought was bombproof, until they tested it with actual people, at which point they realised it just ... wasn't. Respect to Tesco's folks for that - it was a powerful talk.

Accessibility is about the rights of disabled people - removing barriers and tackling ableism. Usability is about making something easy to use in general. They overlap but it's important to centre disabled people in accessibility work

None. Differences are only artificial for namedropping in my opinion. If i cannot use it, it is not accessible. If it is not accessible, i cannot use it.

an example of where I don't think they overlap - bad or missing alt text. If an important image was missing for sighted people, we wouldn't call that a usability issue I don't think, it would be a bug

Usability is like finding the perfect coffee shop! Accessibility is making sure everyone can reach that caffeine fix, even if they prefer tea! 😅

If something is not accessible, then it isn't usable. If something is accessible, it still may not be usable. If something is usable, it may not be accessible. Two distinct concepts that need to meet in the Venn diagram of web design.

Usability - how easy something is to use for a user. Accessibility - how easy something is to use for a user with disabilities. You can consider the former without the latter if you have an exclusive definition of user. An example would be using colour in a design that would be helpful to one user but be useless to another who had a colour blindness. In ‘physical’ product design you tend to hear more about “universal design” which I have always found to be a better emphasis. And there you have the classic examples like Smart Design’s Oxo GoodGrips peeler where making something better for a user with a disability made it better for everyone.

I always loved this quote from Jamie Knight when we worked together at the BBC. I don't think there's a difference. 'In a nutshell accessibility and usability are just us working to ensure environments don't disable people' - Jamie Knight

Usability = how easily users can interact with a product and achieve their goal, so efficiency and satisfaction Accessibility = equal access for individuals with disabilities, addresses their needs so their impairments don't exclude them from using the same product