How big a problem is accessibility on the Web? A report called Beyond ALT Text, published late in 2001 by Kara Pernice Coyne and her colleague, usability expert Jakob Nielsen, gives us a way to begin measuring the dimensions of the accessibility barrier.
The purpose of the Section 508 accessibility standards and the WCAG 1.0 is to establish parity between the experiences that people with and without disabilities have when they use Web-based resources. Beyond ALT Text gives us, for the first time, a measure of how great the disparity between these two groups is.
According to Coyne and Nielsen [2001, p. 3], users with disabilities were about three times less likely to succeed than users without disabilities in carrying out such routine Web tasks as searching for information and making purchases.
That's a huge discrepancy and it's not as though the control group of users without disabilities did all that well, either. The control group succeeded 78.2 percent of the time, as against about 26 percent for the users with disabilities [p. 4]. Twenty-six percent is just plain embarrassing. But the figures for people using screen readers and screen magnifiers are even worse: 12.5 percent and 21.4 percent, respectively [p. 4]. Coyne and Nielsen are careful to point out that these figures do not reflect incompetence or inexperience on the users' part: test participants who were blind had been using computers and assistive technology for more than three years [p. 127], and many of them were employed as knowledge workers [p. 124]. But even 78 percent is only a C+! Nothing to write home happily about. And 78 percent is high, say Coyne and Nielsen typically, usability studies find that the success rate is between 40 and 60 percent. That's an F. The good news is that there's really no place to go but up.
No one means for it to be like that we've never met anyone who deliberately set out to make a Web site that would be inaccessible to 50 million people (except for training purposes). But it happens just the same, not just once or twice but many times. Great Web experiences don't happen often enough for anyone, but for people with disabilities, great Web experiences are downright rare.