Study design

To evaluate the effect of COWP-NE on child willingness to consume selected samples of fruits and vegetables, evaluators from the COWP programme team conducted a quasi-experimental, pre-post design. The design included the collection of plate waste evaluation data at the start and end of the 2015–2016 school year within two groups: (1) randomly selected classrooms receiving the intervention and (2) within conveniently sampled preschool classrooms not receiving the intervention serving as a comparison group. The University of Colorado Institutional Review Board approved all study procedures with an expedited review. Implied consent was obtained from all participating classrooms. Evaluators distributed Memorandums of Understanding outlining the evaluation process to all participating preschools which were then signed and returned by preschool directors. Evaluators noted first name and last initial of participating students during data collection to enable Time 1 and Time 2 matching, and data were then de-identified at the analysis stage.