Usability and Accessibility – are they the same thing?

The more I study UI Consistency and improving the user experience, and the more feedback I hear from customers who use accessibility features, I’m really starting to wonder if Usability and Accessibility are really just two sides of the same coin?

Yes, there is a difference between the two.

  • Usability – how well a user understands the UI
  • Accessibility – the ability to use the UI

Is it possible to have one without the other?  Is it possible to have good usability without good accessibility?  Is it possible to have good accessibility without good usability?  Let’s say that i have perfect MSAA support for a feature that works perfectly with Assistive Technologies.  Is it possible to have good usability without having good accessibility?

I don’t know yet.

I’m leaning towards “no, you can’t have one without the other because they are the same thing.”  During one of my 28 hours worth of meetings this week, I mentioned that if i went to graduate school for CS, i would probably write my thesis on this topic.

What do you think?

Comments (8)

  1. moo says:

    Yes we all love the "My <insert folder name here" Folder spam, My documents, my pictures, my this my that, STOP IT DAMMIT. I have to hack all those crap things OUT!

    Next up we have XP Loony Crayola Crayon theme, then Longhorn QuickTime CopyCat with Extra Spascitcated Borders!


    Then, INDUCTIVE UIs, well yes we all like clicking things 82758759 times just like a web page to do ONE simple operation.

    No, XP at the usability and user level SUCKS, and Longhorn looks worse. I for one will not use it.

  2. sara ford says:

    I’ve deleted a comment here due to offensive language. I respect everyone’s right to have an option, lord knows i have enough of my own. But if you can’t articulate yourself without using language from South Park, don’t bother posting.



  3. moo says:

    Welcome to your user base. We hold the money that you want.

  4. moot says:


    If you expect your posts to be taken seriously then you need to drop the 12 year old conversation style. Do you really think the way you state your opinions is constructive?

  5. To me, usability is about intellectual means and accesibility about physical means.

    It is certainly possible to have good usability without accesibility:

    For example, when a certain button is really hard to get at from the keyboard (e.g., when the mouse breaks), it is an accesibility problem.

    When my mouse works OK but it isn’t easy to find where to click, that is a usability problem.

    Maybe there are some issues not easy to clasify. For example an error message that goes off the screen when using East Asian fonts and becomes uncomprehensible. I would classify this as accesibility, it is caused by a physical issue, font size, however it produces an usability problem, the user can’t understand it. You can choose whether you prefer to classify primarily from the cause or from the effect.

  6. Tim Marman says:

    I definitely don’t think they are the same thing.

    Usability deals with how intuitive an interface is in the "normal" case, while accessibility deals users with disabilities, physical or otherwise.

    [ W3 includes users with "small screens" and "noisy environments" in this group alongside those who are blind and color blind. ]

    An interface that doesn’t work in downlevel browsers, when images are turned off, or without ALT tags on the images wouldn’t be considered very accessible – but that doesn’t preclude it from being usable to the normal user.

    Along the same lines, a web page designed for lynx might be very accessible, but I personally wouldn’t consider that very "usable" by our standards.

  7. moo says:


    If you expect your posts to be taken seriously then you need to drop the 12 year old conversation style. Do you really think the way you state your opinions is constructive?"

    But I am 12.

  8. I’m going to be a bit indulgent and climb on my soap box for a minute. Making sure your application is

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