Teacher preparation lost its way in the 20th century when it dethroned academic content knowledge and put pedagogy in its place. But not only are times ripe for content's return, they actually demand it. Don't take our word for it: these are the conclusions of leading scholars at the University of Michigan's School of Education in two articles in this month's American Educator.

Jeffrey Mirel explains how John Dewey's "progressive" critique of reigning instructional orthodoxy in the early 1900's gradually came to be seen as license to eschew content knowledge preparation for teachers altogether. And because states and districts never came to a curricular consensus, teacher preparation programs saw little value in ensuring that their candidates had mastered a discrete body of knowledge. With teachers so woefully prepared, textbook writers like the enormously influential Paul Hanna could barely touch upon fundamental academic concepts, observing as early as 1934 that such references "would scare most teachers not having had anything in these fields."

To escape from this vicious cycle, Deborah Ball and Francesca Forzani propose a "common core curriculum" for teacher preparation that would enable novices to teach the Common Core standards effectively. Teachers need to have much more than a merely "procedural" knowledge of the subjects they teach; they have to understand how actual subject-area experts build up the knowledge in their disciplines. On top of such content knowledge mastery, they argue that new teachers should learn a set of "high-leverage" practices in questioning techniques, assessment, parent and family engagement and other areas.

What Mirel, Ball and Forzani propose to put in place of current teacher preparation practices amounts, at best, to a plan for further research. The "pedagogical content knowledge" Mirel champions is ill-defined, and at times he seems more interested in carrying forward Dewey's legacy than seeing whether it will help students learn. Ball and Forzani's research program seems much more practical, and will generate propositions that have the virtue of being falsifiable. And it's certainly progress when such prominent teacher educators are willing to offer a diagnosis for what ails teacher preparation.