This research and intervention strategy has some limitations. Notably, there was considerable loss of teacher report data in two of the three sites. The problem with retention in this study was not a function of individual teacher refusal, but rather the process of obtaining school permission. In this phase of the study, we had coupled teacher report with direct observations of student behavior in the public school setting. Understandably, school districts were more cautious with this form of data collection, and therefore were more likely to decline participation. However, an analysis of the participants with missing data on teacher ratings does not suggest severe differences with those retained in this assessment. Moreover, we ran the models for the one site with 75% retention in the teacher ratings and found the same pattern of intervention effects as those reported on the full sample.
