Studies find that having a master’s degree isn’t consistently correlated with student achievement. Nor is years of experience in the classroom, once the first several years of teaching are out of the way. Coming from a Teach for America background, or another alternative route into teaching, appears to make little difference relative to traditional teacher training. Unfortunately, even additional teacher training after the start of a teaching career appears to make little difference when the measure of success is student learning. Yet, great teachers consistently get students to learn much more than mere average teachers. Hanushek and others use statistical analysis to calculate that the students of great teachers tend to learn a year and a half’s worth of information during the school year.