2.1. Research Design
Obesity
OBESITY
This study employed a waitlist-control group, RCT, to assess the impact of the Preventing Obesity by Design (POD) Gardening intervention [The 15 ECEs were randomly assigned to three groups. The 15 ECEs were randomly assigned to one of three groups. Assignment was stratified by the percent of children at an ECE receiving outside funding to pay cost of attending (subsidization level) in order to balance this factor across groups. Group 1, “intervention”, received the intervention in year 1 (5 centers); Group 2, “waitlist control”, or “delayed intervention”, served as the control in year 1 and received the intervention in year 2 (5 centers); and Group 3, “no-intervention control, joined the study in year 2 as a control group and did not receive the garden intervention (5 centers). As an incentive, Group 3 received the garden installation and training resources upon the completion of the study. Baseline data were collected in spring, year 1. Group 1 (intervention) then received the garden intervention in the summer of year 1. Follow-up data collection for Groups 1 and 2 was completed in early fall, following the intervention. In spring of year 2, the procedures were repeated, collecting baseline data from Groups 2 and 3. Group 2, the waitlist control ECEs, then received the garden intervention in summer, year 2. In fall of year 2, follow-up data were collected for Groups 2 and 3. Thus, Groups 1 and 3 each have one pre-intervention measurement and Group 2 has three measurements prior to the intervention. Group 2′s multiple pre-tests enhance the research design by allowing us to rule out alternative explanations (threats to internal validity) [