36 CFR Part 1194 - Proposed Information and Communication Technology (ICT) Standards and Guidelines NPRM - Preamble

3. Comparison of WCAG 2.0 to Existing 508 Standards

While the WCAG 2.0 Success Criteria build on the heritage of the existing 508 Standards, they are generally more explicit than the standards. Careful attention was given during their development to ensure that the Success Criteria are written as objectively testable requirements. In addition, unlike the existing 508 Standards, WCAG 2.0 is written in a technologically neutral fashion, which makes it directly applicable to a wide range of content types and formats.

For example, operability of ICT through keyboards (or alternate keyboard devices) is often critical to accessibility. Persons who are blind or who have limited vision often use screen readers to navigate Web pages using only the keyboard. Keyboard operability is also essential for many individuals with motor impairments who use alternate keyboards, or input devices that act as keyboard emulators when accessing ICT because they find mouse pointing to be cumbersome or impossible. Keyboard emulators include voice recognition software, sip-and-puff software, and on-screen keyboards. The existing 508 Standards envision keyboard operability from both software and Web-based information or applications, but such requirements were not necessarily explicit. Section 1194.21(a) expressly mandates that, when software is designed to run on a keyboard, all product functions must generally be executable through a keyboard. With respect to Web-based information and applications, the 508 Standards are not so explicit. At the time these standards were promulgated, Web pages created with HyperText Markup Language (HTML®) were always keyboard operable. Therefore, an express requirement for keyboard operability by Web pages was unnecessary. The existing 508 Standards expressly require keyboard operability for Web pages that require applets and plug-ins to interpret page content since keyboard operation in these contexts was not ubiquitous. See 36 CFR 1194.22(m). Collectively, the existing 508 Standards thus address keyboard operability both within and outside the Web environment, but do so in a variety of ways.

Over the years, however, Web technologies have become more complex. Use of keyboards is often secondary to mouse or touch-only interfaces. Success Criterion 2.1.1 requires all functionality to be operable through a keyboard interface. Section 1194.21(a) of the existing 508 Standards requires that “[w]hen software is designed to run on a system that has a keyboard, product functions shall be executable from a keyboard where the function itself or the result of performing a function can be discerned textually.” This current wording is phrased as an input requirement based on output, and it leaves “discerned textually” as an undefined term. These are both flaws that may create accessibility gaps in application. For example, an operating system feature like “mouse keys” (where the keyboard cursor keys are used to steer the mouse pointer) satisfies this provision on its face, even though that feature is of no use to someone who cannot see the screen and relies on screen reading software. Success Criterion 2.1.1, on the other hand, while longer, only references input and uses no special jargon. This success criterion reads: “All functionality of the content [must be] operable through a keyboard interface without requiring specific timings for individual keystrokes, except where the underlying function requires input that depends on the path of the user's movement and not just the endpoints.”

The Access Board has created a comprehensive table comparing WCAG 2.0 Level A and AA Success Criteria to the corresponding requirements in the existing 508 Standards. The table can be found on our website at www.access-board.gov/wcag2-508. In this table, the Board has identified WCAG 2.0 success criteria as either “substantially equivalent” or “new” relative to the existing 508 Standards. Identification of a WCAG 2.0 success criterion as “new” indicates that it has no corresponding provision in the existing 508 Standards; rather, it addresses a deficiency with the existing 508 Standards as identified by the developers of WCAG. In most cases, agencies with Section 508 compliance testing processes have adapted their procedures to address these accessibility concerns.

In sum, there are 38 WCAG 2.0 Level A and AA Success Criteria. After careful comparison of these success criteria to the existing 508 Standards, the Access Board deems 22 success criteria to be substantially equivalent in substance to our existing standards. The Board estimates that agencies with content that meets this group of existing 508 Standards will incur no or minimal costs by virtue of incorporation of WCAG 2.0 into our proposed rule. For the remaining 16 success criteria the Board deems to be new, it is anticipated that agencies would, to a greater or lesser extent (depending on the content and criteria at issue), incur some costs when implementing WCAG 2.0.

Question 6. The Board seeks comment on the extent that the proposed incorporation of WCAG 2.0 Level A and Level AA Success Criteria would result in new costs or benefits. We have characterized the majority of success criteria as “substantially equivalent” to requirements under the existing 508 Standards and 255 Guidelines and request comment as to the accuracy of this characterization.