Teaching research is unfortunately fairly balkanised and my brief stint in the science of teaching was in German, so I could, for the most part, only offer refe

Teaching research is unfortunately fairly balkanised and my brief stint in the science of teaching was in German, so I could, for the most part, only offer references to German text books. However, it’s established that active learning increases student performance significantly [1], and systematic active learning was only introduced into curricula fairly recently (and not yet pervasively). Where this was done this has by necessity caused an at least partial “grade inflation” but I’ll admit that its adoption is far from satisfactory so (as my comment already noted!) it might not be sufficient to explain grade inflation. [1] https://www.pnas.org/content/111/23/8410.full https://www.pnas.org/content/111/23/8410.full