Types of problems elicited by verbal protocols for blind and sighted participants

Verbal protocols are often used in user-based studies of interactive technologies. This study investigated whether different types of problems are revealed by concurrent and retrospective verbal protocols (CVP and RVP) for blind and sighted participants. Eight blind and eight sighted participants undertook both CVP and RVP on four websites. Overall, interactivity problems were significantly more frequent in comparison to content or information architecture problems. In addition, RVP revealed significantly more interactivity problems than CVP for both user groups. Finally, blind participants encountered significantly more interactivity problems than sighted participants. The findings have implications for which protocol is appropriate, depending on the purpose of a particular study and the user groups involved.