Are CAPTCHAs Accessible?

Question

I am writing a website in my spare time for an educational facility and from what I've read on the statistics of this place they seem to have many disabled students studying there. Simply put, I'm setting up an account system where students can log in and receive basic information about their courses, allowing them to comment on their courses and how they felt the course represented them.

I'm not too sure on the legal implications of this, but I am pretty sure that if you are working for an educational body then it is a legal requirement for your website to be accessible to those with disabilities. The code is perfectly fine, apart from one problem; the CAPTCHA.

As far as I am aware most CAPTCHAs are image-based, which will make those using screen readers struggle. On top of that, ones that support sound readings may not work too well as in many buildings there are no speakers for the user to listen to the recording. I could always use a small field asking a user to put two numbers together but those are often far too easy for bots to attack.

I may be making a mountain out of a molehill but it's still an interesting question for those that have an interest in accessibility. Does anyone know of a good way to keep spammers out and users in within this environment?

Answer 1

First of all, yes you are 100% correct that it is an issue. Any captcha that provides images with garbled text are NOT accessible to screenreaders, and if you are in an organization that has to support it, you CANNOT just use a captcha.

Secondly, I personally agree 100% about the limitations of a audio captcha as well.

Personally I would implement a standard Captcha such as ReCaptcha or something similar then have a "can't see the image" link, that takes them to a less secure captcha, if you really need to have one. It really depends on the purposes of your site. Simple math can work, but it is a bit harder to do.

But given your system, I'd almost say that you limit the system to authenticated users for input, and then not require a captcha for comment or other submissions, as that avoids the issue.

This site shows an example of other text based captcha items, but depending on the audience they may or may not be possible.