Students already know much of what we’re supposedly ‘teaching’

Graham Nuthall said:

Our research shows that students can be busiest and most involved with material they already know. In most of the classrooms we have studied, each student already knows about 40-50% of what the teacher is teaching.

via The Hidden Lives of Learners, p. 24
We could solve this by pre-testing, yet not enough of us do…
Hat tip: Carl Hendrick