How can formative assessment work for both learners and teachers?

'Imagine what a difference it would make if children knew what they were good at and what they had to do to improve.' With these stirring words, our trainer extolled the benefits of feedback. Teachers should make sure students were absolutely clear about where their work needed further crafting and provide them with time to do this. It was, and still is, a compelling vision. So what went wrong? What went wrong was that feedback was interpreted as meaning marking. And not just any old marking - dialogic marking. Fast forward 10 years and schools were marking within an inch of their lives. The toll on teachers was terrible; there just weren't enough hours in the day to get the marking done. Yet this toil had dubious actual impact on learning (Elliott et al., 2016). So it was a surprise when I discovered that Dylan Wiliam, prime advocate of 'feedback', has little to say about marking per se, let alone labour-intensive dialogic marking. He describes feedback as anything that lets the