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Re: Difference between JAWS and NVDA for accessibility testing

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From: Steve Green
Date: Jun 11, 2019 3:51PM

Firstly, you need to decide why you want to test with a screen reader. The two main reasons are to assist with a WCAG audit and to understand the user experience i.e. conduct an expert review. They are completely different activities and you may use different screen readers for each.

If you want to use it to help with a WCAG audit, I would recommend NVDA because JAWS uses more heuristics than NVDA. The heuristics provide a better user experience with non-compliant code, but it means that JAWS hides non-compliances that would show up with NVDA. Both products have bugs, but I can't say which is better in that respect. That's why you should always report WCAG non-compliances in terms of the code, not in terms of screen reader behaviour.

Bear in mind that you do not need to use a screen reader in order to do a WCAG audit. It can be useful, but it's by no means essential. If you do use a screen reader for a WCAG audit, you only need to use one version with one browser.

Alternatively, if you want to know about the user experience, use JAWS because it is still the most widely-used screen reader. Better still, use both if you have the time and money, and don't forget Voiceover and Talkback. There are a vast number of permutations of screen reader versions and browsers - far more than anyone ever tests with. Screen reader behaviour changes from version to version far more significantly than browser versions. You will need to decide on a testing policy, such as only testing with the latest version or perhaps the latest and one earlier version (perhaps 2 or 3 versions old).

Perhaps even more important is training. Pay a professional trainer to teach you to use the screen reader properly. Do not teach yourself!!! I frequently see testers and developers (at other companies, not mine!) using screen readers completely wrongly. Also, spend time observing real screen reader users to get an understanding of the strategies they use for navigating websites and individual pages. Learn what they find easy and difficult - it may not be what you expect. You will need to pay people to participate in this, but it's well worth the time and cost.

Steve Green
Managing Director
Test Partners Ltd