Since June 2001, federal regulations have required that U. S. Government Web sites and other software developed by or for the U. S. Government provide comparable access to the information for all users. Per these regulations, computer users who have visual and/or other disabilities are entitled to have the same access as users who do not currently have any disabilities.

Some practitioners consider accessibility to be a subset of usability, while others think of accessibility as related to, but separate from, us ability. The staff of the Census Bureau’s Usability Lab consider usability to be an issue for all users, no matter what their abilities or disabilities may be. Thus, a user interface must be both accessible in the ways required by the federal regulations and usable for people with disabilities.