Notes: The district data are drawn from the U.S. Department of Education National Center for Education Statistics Common Core of Data, from the year prior to our study (school year 2012—13). Only local school districts and charter agencies are included; supervisory union administrative centers, regional education service agencies, state agencies, and federal agencies are excluded. Means and differences are computed giving each district equal weight. Differences are calculated from a linear regression controlling for treatment status and no other covariates. Standard errors (SE) are reported in parentheses. FRPL = free or reduced-price lunch; IEP = individualized education plan; LEP = limited English proficiency; FTE = full-time equivalent.

^***Significant at the 99% level.

Notes: Our model regresses the dependent variable against fixed effects for randomization strata, an indicator for our mediator of interest (good prior relationship/high baseline rating/ten or more years of experience), a treatment indicator, and the interaction between our mediator and the treatment indicator. Standard errors are reported in parentheses, and allow for clustering within-school. Good prior relationship with administration is defined as answering “Very” or “Quite” to the question “Overall, how much do you enjoy working with your administrator” on the baseline survey. Seventy-five percent of teachers fell into this category. High administration baseline rating is defined as a teacher's administrator answering “top 5%” or “top 25%” to the question “Among all the teachers you have known who taught the same grade/subject, how would you rate the overall quality of instruction provided by this teacher?” on the baseline survey. Fifty-one percent of teachers fell into this category. Years of experience are taken from our baseline survey. Sixty-two percent of teachers reported having ten or more years of experience.

^**Significant at the 95% level; ^***significant at the 99% level.