We developed a longitudinal data set based on teacher and principal surveys, participant records, and school demographics that allowed us to measure implementation over time and to identify program and school characteristics that predicted the increase or decrease in participation. We found early indications of uptake and enthusiasm for Reading Apprenticeship, but greater variation in responses across schools by the third year. Using regression analysis, we found that initial teacher participation in team meetings and schoolwide commitment predicted “scaling-in” within a school. We hypothesized that a process, consistent with SLI's use of cross-disciplinary teacher teams, led to increased and sustained program participation. This study contributes to the field of scale-up research through identifying intermediate teacher outcomes that predict scaling-in and that were not as prevalent in an RCT conducted in parallel, illustrating the weakness of large-scale RCTs as an appropriate context for measuring impact of an innovation that is being scaled up. 相似文献