Education Secretary Arne Duncan speaks about the administration’s priorities for education at Seaton Elementary in Washington in January. (Jacquelyn Martin/AP)

Education Secretary Arne Duncan said Monday that his agency deserves a “low grade” for its efforts so far to overhaul regulations for teacher-preparation programs, saying that too many K-12 educators are not ready for the classroom.

“We have light years to go, we have so far to go,” Duncan said, speaking in Washington at the annual legislative conference of the Council of Chief State School Officers. We’ve changed the world in some pretty profound ways, but we have not changed the world in that way.”

Teacher-preparation programs are often criticized, including by educators themselves, for being mediocre and for focusing too heavily on the theory and history of education at the expense of equipping teachers with the hands-on skills they need to work with students.

The Obama administration would like to require states to rate teacher-preparation programs, including those at public and private universities and at alternative organizations such as Teach for America. Such ratings would for the first time consider how teachers in training perform after graduation, including how long they work in the classroom and how their students perform on standardized tests.

Duncan’s first effort to develop such a rating system collapsed in 2012. His agency is now trying again: Officials released draft regulations in November and plan to release final regulations in the fall.

More than a dozen education school deans, including at the University of Virginia and Johns Hopkins University, have formed an organization that supports the proposed regulations.

But many colleges and some education experts have bristled at the prospect of evaluating teacher-preparation programs according to the test scores of their graduates’ students. If medical schools were evaluated according to the patient mortality rates of their graduates, some have said, then there would be no incentive for medical students to go into fields where they would encounter the sickest people.

There is already little incentive for teachers to work in the most difficult schools, Duncan acknowledged Monday, saying that he is bothered by the fact that neither his agency nor state departments of education have figured out a way to get the best teachers into the most difficult schools.

Duncan said he had recently visited an American Indian reservation where the tribal school’s staff was half teachers from overseas and half Teach for America members. The school couldn’t persuade anyone else to work there.

“There is not a state that has taken this on in a real way,” Duncan said. “That’s got to become the capstone of a great career, to go work in the inner city or in a tribal school, and we haven’t had that mentality.”