As seen in 90% of All Usability Testing is Useless, two quotable paragraphs by Lane Becker.
Ninety percent of all usability testing performed on Web sites is useless. This is not to say that it doesn't have a significant role to play in user experience design. When done right, usability testing will improve your Web site and your development process, but the current culture surrounding Web site usability testing is such that it rarely benefits the design. Worse, this misapplication can undermine the acceptance of this important technique throughout an organization.
Substitute “accessibility” for “usability” in the above. Perhaps a bit controversial (given that we do a lot of web accessibility testing), but it still summarizes it nicely. Here’s the second, with the same substitution:
When viewed as a sort of quality assurance, as it classically is, usability testing becomes a late-stage "nice-to-have," less important than getting the newest version of the Web site out the door. It usually results in a thick document that outlines everything that's wrong with a Web application, including fundamental design issues that can't be fixed in the few weeks left before launch. This isn't the best way to effect positive change.
I’m sure there are others that fit well…
