Background: Rigorous meta-analysis holds promise to answer the ultimate important question in education: which interventions work and for whom? Evidence-based reform in education has contributed to a proliferation of well-designed experiments in recent years, which calls for updated systematic reviews. However, this proliferation is a double-edged…

It is well documented that teachers can have profound effects on student outcomes. Empirical estimates find that a one standard deviation increase in teacher quality raises student test achievement by 10 to 25 percent of a standard deviation. More recent evidence shows that the effectiveness of teachers can affect long-term student outcomes, such…