The effect of certification and preparation on teacher quality.

To improve the quality of the teacher workforce, some states have tightened teacher preparation and certification requirements while others have eased requirements and introduced "alternative" ways of being certified to attract more people to teaching. Donald Boyd, Daniel Goldhaber, Hamilton Lankford, and James Wyckoff evaluate these seemingly contradictory strategies by examining how preparation and certification requirements affect student achivement. If strong requirements improve student outcomes and deter relatively few potential teachers, the authors say, then they may well be good policy. But if they have little effect on student achievement, if they seriously deter potential teachers, or if schools are able to identify applicants who will produce good student outcomes, then easing requirements becomes a more attractive policy. In reviewing research on these issues, the authors find that evidence is often insufficient to draw conclusions. They do find that highly selective alternative route programs can produce effective teachers who perform about the same as teachers from traditional routes after two years on the job. And they find that teachers who score well on certification exams can improve student outcomes somewhat. Limited evidence suggests that certification requirements can diminish the pool of applicants, but there is no evidence on how they affect student outcomes. And the authors find that schools have a limited ability to identify attributes in prospective teachers that allow them to improve student achievement. The authors conclude that the research evidence is simply too thin to have serious implications for policy. Given the enormous investment in teacher preparation and certification and given the possibility that these requirements may worsen student outcomes, the lack of convincing evidence is disturbing. The authors urge researchers and policymakers to work together to move to a more informed position where good resource decisions can be made.