Collaborative Expertise

This weekend I was reading the latest paper by John Hattie. I enjoyed reading it because it insists on collaborative expertise. I am a fan of collaborative practice. After all, teachers are teacher's greatest resources. Hattie has suggested eight ways to minimise variability in Teacher expertise within schools. As I was reading his paper, a lot of questions came to my mind like: Which assessments can measure impact? Are we wasting time doing assessments that actually do not provide greater insight into progress a student has made? How can we be more collaborative and stop labelling teachers and students? How can we set conditions for collaborative practice? Is student progress fixed to teacher or are there other variables that could be contributing to progress? Are we too obsessed by the word 'Achievement'? etc.
I have summarised what Hattie says in a presentation below.