Experimental evaluation of usability and accessibility of heading elements

Task completion times of sighted and blind users were measured with two kinds of Web sites: sites marked up appropriately with heading elements and sites with the same visual appearance but with no heading elements marked up. The experiment was carried out with user agents that could navigate through heading elements. The results showed that 1) task completion time was reduced by as much as one half with marked up heading elements, 2) the benefits of markup on task completion time were greater for blind users, and 3) the overall difference in response time between sighted and blind users diminished with sites that were appropriately marked up.