"Using exogenous secondary school assignments to remove self-selection bias to schools and peers, I obtain credible estimates of (1) the effect of attending schools with higher-achieving peers, and (2) the direct effect of peer quality improvements within schools, on the same population. While...

"Unlike in elementary schools, high school teacher effects may be confounded with unobserved track-level treatments (such as the AVID program) that are correlated with individual teachers. I present a strategy that exploits detailed course-taking information to credibly estimate the effects of...