Under the PCER initiative, 12 research teams received peer-reviewed grants to implement one to two preschool curricula of their choosing under an experimental design. For each team’s evaluation, preschool classrooms or programs were randomly assigned to use the treatment or control curricula. The treatment curricula included sufficient standardized training procedures and curriculum materials to be implemented in typical early childhood education settings. RTI and MPR evaluated the impact of each curriculum using a common set of measures. The curricula, corresponding research team, research site, and evaluator are listed in table A. Three teams each implemented two curricula. Two teams implemented the same curriculum, Creative Curriculum. Four teams had originally developed the curricula that they implemented (Curiosity Corner; Literacy Express, Pre-K Mathematics supplemented with DLM Early Childhood Express Math software, and Early Literacy and Learning Model [ELLM]). RTI evaluated eight curricula implemented by seven teams (including one curriculum that was evaluated by two teams) while MPR evaluated six curricula implemented by five teams. In sum, 14 curricula (one twice) were evaluated.
The 14 curricula were evaluated in comparison to the local control condition that, in general, was the local curriculum-as-usual. As a result, multiple curricula were used across the control sites and within some of the individual evaluations. These included teacher-developed nonspecific curricula with a focus on basic school readiness, district-developed curricula, and published curricula (some of which were implemented by other research teams). The control curricula are identified in the section on Findings by Curriculum at the end of the Executive Summary. As a result of the use of different control curricula among the evaluations, this report does not make cross-intervention comparisons.
Rather than one overall evaluation, the PCER study contains individual evaluations for each curriculum, for three reasons. First, each research team worked independently. Second, the selection of the intervention and the randomized assignment occurred at the team level. Third, different control curricula were used with each intervention curriculum.