Designing an Evaluation study of the California Children's Power Play! Campaign: Recruitment strategies and lessons learned from a nutrition and physical activity intervention

Background: The 2011-12 impact evaluation examines the effectiveness of the Power Play! Campaign, a social marketing initiative that empowers 4th and 5th graders from low-resource schools to eat fruits and vegetables and get 60 minutes of physical activity each day. Purpose: To describe the strengths and limitations of the study design and provide lessons learned on school recruitment and retention. Significance: To examine the role of Power Play! on students' eating and physical activity habits, approval for the evaluation was granted by the district, principal, teacher, parent, and student. Methods: The study design is a quasi-experimental intervention-control trial of approximately 4000 4th and 5th graders representing four San Diego county school districts. Out of 131 eligible schools, 45 schools were recruited and randomly assigned into intervention (n=23) or control (n=22) groups. This sample size was selected to be able to detect a 1/3 cup difference in intake of fruits and vegetables (primary outcome) between control and intervention groups. After baseline data was collected at all schools, the 10-week Power Play! Campaign was implemented in the intervention schools, with control schools maintaining their usual activities. Post-intervention data was collected in spring 2012, soon after Campaign completion. The study design included an opt-out consent process, extensive training of 27 data collection staff, and teacher and school incentives to maximize success. Findings: Although schools have competing demands and obligations, many schools were willing to participate in this study. Multi-level recruitment strategies at the district and school level and lessons learned will be discussed.