Web accessibility means people with different abilities can access, understand, and navigate web content, regardless of how they’re accessing it.
Section 508 of the Federal Rehabilitation Act of 1973 requires US Federal Government agencies to maintain websites that are accessible at "comparable" levels to government employees and members of the public with a disability.
More specifically, Paragraph 1194.22 of the law lays out the accessibility requirements for websites, and those are the standards against which we measure each website.
Why Accessibility Is Important
First, citizens should be able to access the government resources that they are entitled to.
Second, web accessibility is a legal requirement for Federal Agencies.
To put this issue into perspective, consider the follow statistics published by the US Census Bureau in 2012:
- 19.9 million Americans (8.2% of the population) have difficulty lifting or grasping, which could impact their usage of a mouse or keyboard.
- 8.1 million (3.3%) have a vision impairment, which could require them to use a screen magnifier or a screen reader.
- 7.6 million (3.1%) have a hearing impairment, which could require them to rely on transcripts and/or captions for audio and video media.
For more information, see the report Americans with Disabilities: 2010 on the Census Bureau's website.
What Does Fed A11y Do?
We use pa11y to scan US Federal government websites using a Section 508 Ruleset to identify some - but not all - of the accessibility shortcomings in some - but not all - U.S. Federal Government websites.
Automated accessibility testing software cannot identify every accessibility issue. Take these two examples:
- Although we can automatically check if an image has an alt text attribute, we cannot determine if that alt text is actually describing the image. For example, the scan would not flag a picture of a hotdog that has an alt text attribute that reads “not a hotdog”. In reality, the alt text is incorrect and the image is therefore not accessible.
- Although we can detect the background color and text color by reading a page’s Cascading Style Sheets (CSS), we may not be able to detect the color of an image itself. If dark text is overlayed on a dark background image, we would not be able to measure whether the level of contrast is sufficient.
Another limitation is that we don't have access to the complete list of .gov websites. We do our best by starting with the General Services Administration's official list , but this isn't exhaustive and is additionally prone to typos and inconsistencies in Agency and Organization names.
Finally, we do not completely index the websites that we scan. We only scan their home pages. However, we do plan to scan every page on a domain's sitemap sometime soon.
It is for these reasons that fully assessing a site’s accessibility still requires manual evaluation by an accessibility professional.
Let the legal hand-waving commence:
- Fed A11y does not provide a complete accessibility evaluation and is not intended to replace an authoritative Section 508 conformance assessment.
- Fed A11y's automated accessibility testing addresses a mere portion of what’s required in order to determine if a website is fully accessible. As a result, it's possible for manual accessibility testing to be reveal false positives/negatives. People should therefore use both manual and automated tests to fully assess whether their website is accessible.
- Only a professional can perform a complete accessibility evaluation. For testing guidance, they can refer to the Harmonized Testing Process for Section 508 Compliance: Baseline Tests for Software and Web Accessibility .