This article attempts to unpack the complexity of teachers' professional knowledge construction in Assessment for Learning (hereafter, AfL). It presents a qualitative study of a school-based AfL Project which took place in a secondary school in Hong Kong. Thirty lessons video-recorded in the AfL Project and nine teacher interviews conducted after…

This paper attempts to identify the distinctive qualities of successful veteran teachers, referred to as "expert teachers", which separates them not only from novice teachers but more importantly from experienced non-expert teachers. Based on earlier case studies, this paper maintains that the critical differences between expert and…