'A half-century of tolerating mediocrity'

Over at Education Next ('Want a 3.8 GPA? Major in Education'), Frederick Hess points us to a new study by University of Missouri economist Cory Koedel, who writes:

Undergraduate education majors become teachers, teachers become principals, and principals become district-level administrators. Ultimately, a sizable fraction of the workforce in the education sector is trained in education departments where evaluation standards are astonishingly low. Should we be surprised that low standards persist in K-12 schools?