A common forecast argues a cadre of professional respondents threaten the validity and reliability of results from market research ? especially Internet-based market research using online access panels. While usefully drawing attention to the issue of quality, this forecast fails to draw distinctions among different types of threats, is based on scant empirical evidence, and provides clients with no way to determine how to move forward. This paper addresses these shortcomings by developing a conceptual framework that clarifies threats, using empirical evidence to determine threats levels, and offers practical suggestions for clients.