Inside the black box: Raising standards through classroom assessment
Black, P. & Wiliam, D. (1998). Phi Delta Kappan, 80(2), 139-148.
Probably the most cited document on formative assessment, this article identifies efforts to raise student achievement levels that failed because they focused on standards and accountability while ignoring what teachers and students do in the classroom. The authors then proceed to summarize the research evidence that improving formative assessment practices significantly improves student performance and to describe how to go about developing better formative assessment skills of teachers.
The concept of formative assessment
Boston, C. (2002). Practical Assessment, Research & Evaluation, 8(9).
This item, in a peer-review electronic journal, very briefly describes formative assessment and some significant research related to it. It is cited here because it identifies several resources for teachers.