David Ausebel developed the theory of Advanced Organisers in 1960.
Essentially, he believed that if students were given a framework before the lesson, they work better be able to apply or understand the concept.
This could be as simple as displaying on a board what you are going to do during the lesson. I do the same with my program for the day.
There is considerable debate in educational forums about the intricacies of this strategy. I leave that to the academics.
All I know is that it works.