Teacher-pupil interaction in formative assessment: Assessing the work or protecting the child?

Many claims are currently being made about the formative role that assessment can and should play in teaching and learning. Such claims derive from a variety of arguments but focus on questions of how children learn and how they can benefit from supportive questioning and constructive feedback. However, we have little empirical evidence with which to evaluate such claims. In particular we have few descriptions or analyses of the sorts of teacher-pupil interaction which would constitute such formative assessment.