Notes: Each bar represents an estimated effect size (i.e., an estimate of the expected change in math value added associated with a one standard deviation change in an input) with the exception of the effect from Goldhaber, Krieg, and Theobald (2017). This estimate of the “optimal match” is based on the authors’ calculation, assuming that student teaching occurs in schools that are estimated to be optimal for value added, according to figure 5 in Goldhaber, Krieg, and Theobald (2017). SD = standard deviation; VA = value added.