Setting Usability Requirements For A Web Site Containing A Form 
We describe the challenges of understanding and setting usability requirements for a web site containing a form. We define 'usability requirements.' Ideally, usability requirements should be defined early in a project. In practice, we often find that the first opportunity we have is when we are asked to undertake an evaluation. Collecting the users' opinions of the requirements as part of the evaluation can often prompt the organization into investigating the users, leading to a better set of requirements and, eventually, a better web site.
Miller, Sarah and Caroline Jarrett. STC Proceedings (2001). Presentations>Accessibility>Web Design>Usability