The Scourge of Online Solutions and an Academic Hertzsprung–Russell Diagram

We report on preliminary results of a statistical study of student performance in more than a decade of calculus-based introductory physics courses. Treating average homework and test grades as proxies for student effort and comprehension, respectively, we plot comprehension versus effort in an academic version of the astronomical Hertzsprung–Russell diagram (which plots stellar luminosity versus temperature). We study the evolution of this diagram with time, finding that the “academic main sequence” has begun to break down in recent years as student achievement on tests has become decoupled from homework grades. We present evidence that this breakdown is likely related to the emergence of easily accessible online solutions to most textbook problems, and discuss possible responses and strategies for maintaining and enhancing student learning in the online era.