We removed students who did not have parental consent to be a part of the study, which left us with 16,879 students. In addition, we had to exclude the 8,979 students (and their 113 teachers from 5 schools) who were missing pretest or posttest data used in our analyses. Most of this missing data was due to a miscommunication between the research team and the district relating to the student identification numbers that students were instructed to use at pre-test. Almost 5,000 students used an incorrect identification number, making it impossible to match students’ pre and posttest scores. Little’s (1988) Missing Completely at Random (MCAR) test confirmed that these data were not missing completely at random (x2 (1576) = 7162.88, p < .001). In particular, students with missing data were more likely to be male, African-American or Hispanic/Latino, with ELL status, and from schools with a high percentage of free or reduced lunch. After removing those students with missing data, we report on the 7,900 students and 226 teachers from 44 schools who remained in our analyses.