Usability Testing: Revisiting Informed Consent Procedures for Testing Internet Sites
http://portal.acm.org/citation.cfm?id=563717&jmp=references&dl=GUIDE&dl=ACM
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  peer-reviewed

Burmeister, Oliver K.
ACM
2000

Abstract:

This paper explores issues of professional, ethical conduct in usability testing centering around the concept of 'informed consent'. Previous work on informed consent has been in homogeneous geographic locations. With Internet sites being developed at a prodigious rate, these procedures need to be revisited for their applicability to heterogeneous locations, in terms of culture, business practice, language and legal requirements. Some previously valued principles might now be considered discretionary, that is their applicability has situational specificity. Other principles are mandatory.