I had come across was based on a widely used conceptual test: the Force Concept Inventory (FCI)
. Six thousand students from high school, college and university wrote this test near the beginning and end of their physics courses. By comparing students’ pre- and post-test scores, a learning gain was calculated to serve as a measure of the effectiveness of instruction. These results are shown in the diagram below where traditional instruction has the coloured symbols. It came as quite a revelation to me that no matter how insightful or entertaining a traditional lecture might be, students have a very limited average gain of 0.23.
A gain of 0.30 seems to be an upper limit on understanding from this mode of teaching. Note, however, that physics programs using interactive engagement techniques show considerably better results.
The low gains resulting from lecture-format instruction were also a surprise to Eric Mazur, a reknowned physics professor at Harvard University. Mazur was an outstanding lecturers who garnered perennial glowing reviews from his first year students. In this video
he recounts the transformational experience of using the FCI. Listening to Mazur shattered my long-held mental model in which students’ understanding was the effect of a mythical “great teacher” at work.