The Importance of formative assessment
"Embedded Formative Assessment" - Dylan Wiliam (2011)
(Book on order for DRC.)
"Formative assessment plays an important role in increasing teacher quality and student learning when it's viewed as a process rather than a tool. Emphasizing the instructional side of formative assessment, this book explores in-depth the use of classroom questioning, learning intentions and success criteria, feedback, collaborative and cooperative learning, and self-regulated learning to engineer effective learning environments for students."
Read introduction and Chapter 5 of the book online
("Providing feedback that moves learning forward".)
Short videoclip of the author
Playlist of assorted D Wiliam clips.
(You may have to click past the 2nd clip if it doesn't play)
Links to some of his published papers.