Teacher preparation study

Teacher's certification method doesn't affect student scores
Students of educators who attend college teacher-training programs and those instructed by teachers certified through other means score no differently on standard reading and math exams, according to a new study that tracked 2,600 students in six states. "When students are placed with teachers with alternative routes versus traditional routes [for certification], there's no harm in terms of student achievement," said Jill Constantine, who directed the study for Mathematica Policy Research.
Mathematica Policy Research. (2009). An Evaluation of Teachers Trained Through Different Routes to Certification. Washington, DC: US Dept. of Education
http://www.mathematica-mpr.com/publications/pdfs/education/teacherstrained09.pdf