Research on student assessment in online environments has not been extensive, although manuals for instructors provide broad guidelines and specific procedures. In this article we review the most frequently reported approaches to online assessment in postsecondary settings, giving particular attention to systems for assessing the quality of student participation. We also extrapolate from research on assessment in face-to-face courses to identify strategies that could be usefully adapted to online assessment. Research on the reliability and validity of online assessment methods is mixed and there is not much of it. We suggest to online instructors that there appears to be a disjunction between assessment methods and instructional ideologies and suggest to researchers that there is an urgent need to investigate the consequential validity of online assessment. (Contains 3 endnotes.)