Crystal Smit

Chapter 4 74 The Active Control Condition In the active control condition, children simultaneously received knowledge about the benefits of drinking water—as an alternative for SSB—through a half-hour classroom presentation. This presentation was delivered by research assistants, and the benefits were the same as those discussed in the training of the influence agents. At the time of the presentation, children who had not received consent from their caretakers to participate in the study went to another classroom with the teacher. Measures Peer Nominations To identify the influence agents in each classroom, the children were asked to nominate at least one peer whom they “wanted to be like”, “regarded as good leaders”, “went to for advice” (Smit et al., 2016; Starkey et al., 2009) and “talked to about what they drink” (Rogers, 2010). For the selection of the influence agents, only same-classroom peer nominations were included. To ensure sex balance in relation to the composition of the classrooms, 15% of boys and 15% of girls in the social network intervention with the most nominations on all items together were selected and trained as influence agents (Smit et al., 2016; Starkey et al., 2009). On average, five children ( SD = 1.06) per participating classroom in the social network intervention schools were trained as influence agents. This resulted in a total of 37 influence agents from eight classrooms. Water Consumption Children indicated on three different days (i.e., every other day during each data collection wave) how much water they drunk the day before (Bevelander et al., 2018; Smit et al., 2018, 2016). Response options ranged from 0 = ‘zero glasses per day’ to 7 = ‘seven or more glasses per day’. An illustration was used to instruct the children that one glass also meant one can, bottle, or package of approximately 200 ml. A total score for water consumption was constructed by averaging the children’s reported consumption over the three days (Cronbach’s α ranged from .65 to .78).