Paul Black's presentation at the LSC PI conference described the value and nature of formative assessment in the classroom. Paul will take part in this discussion and explore this topic further. Possible areas of focus include: Where can we find, or how can we develop, questions that explore students' understanding of the concepts and methods of science? Can we share good examples, sources, and useful ideas to help us invent and evaluate such questions? Who has gotten their pupils to develop the skills and habits of self-assessment? How can peer assessment be encouraged, and how is it best used?