Hendy 2011.

Methods	Design: RCT Timing: Prospective Allocation to group: Random (Quote: "After one month of baseline records, children were randomly assigned to one of the two study groups for three months of reward conditions") Number of clusters or sites: 1 elementary school Number of individuals: Beverage outcome data on 252 children were included in the analyses. Length of intervention: 3 months
Participants	General description of participants: Children in an elementary school in a small town in Pennsylvania, USA Age: Participants were 1st to 4th grade elementary school children Inclusion criteria: Quote: "Of the 457 children who attended the 1st–4th grades at some time during the KCP application, data from 382 (83.6%) children were included in statistical analyses of the present report only if they had been a student at the school throughout the program, and only if they did not have severe disabilities that would make it difficult for them to understand the program" Exclusion criteria: See quote above Recruitment: N/R Weight status at baseline: Quote: "Of the total 382 children in the present study, 341 (89.3%) had BMI% scores available, with 11 (3.2%) being underweight with BMI% scores less than the 10th percentile, with 210 (61.6%) being average‐weight with BMI% scores between the 10th and 85th percentile, and with 120 (35.2%) being at risk for overweight or obesity with BMI% scores above the 85th percentile" SSB consumption at baseline: Not reported in the study's published report; based on information provided to us by the corresponding author, the most popular beverage at baseline was sugar‐sweetened chocolate‐flavoured milk Equity considerations: Quote: "[T]he present Kids' Choice Program (KCP) was conducted with a sample of school‐aged children from a small‐town in eastern Pennsylvania and with mostly Caucasian children. Future KCP applications could be examined in schools with more regional and ethnic diversity (...)". Participants were over 95% white, and included 211 boys and 171 girls. Children with severe disabilities were excluded
Interventions	Intervention: Token rewards for children choosing healthy beverages during school lunch. (Quote: "The Kid’s Choice Program (KCP) was developed as an easy‐to‐use and relatively inexpensive school‐based intervention to improve well‐documented changes in children’s weight management behaviors. (…) The KCP includes three simple school procedures: (1) children wear nametags during school lunch and recess; (2) star‐shaped holes are punched into the nametags when children exhibit small amounts of specific weight management behaviors, with at least two choices being available for each behavior; (3) Reward Days are presented once each week when children can trade their stars for small prizes. (…) Reward Days were offered each week so children could trade 10 stars for one small prize (pens, fancy pencils, notebooks, modeling clay, puzzles, banks, toy gliders, stickers, water bottles, playing cards, jump ropes, stuffed animals, balls, silly hats, etc.). A large table was set up in the corner of the lunch room with large plastic bins containing a selection of five or six prizes. During the last 10 min of the lunch period for each grade, children were called by classroom to line up along the edge of the lunchroom to approach the table and trade their 10 stars for a prize of their choice. Children were given new nametags each week, but allowed to keep leftover stars toward the next week’s Reward Day") Behavioural co‐intervention: None reported Control: Alternative intervention (Quote: "The control group (...) received stars punched into their nametags for each of three ‘Good Citizenship Behaviors’ that included talking quietly during meals, keeping their meal area clean, and respecting others by not touching them or their things"
Outcomes	Measures of SSB intake: The average number of days per week (= 6 days) in which children chose an unhealthy beverage (defined as SSB, sugar‐sweetened milk, and whole plain milk) for lunch, assessed by trained observers on 3 days each week during baseline and continuously throughout the 3‐month intervention phase Measures of intake of alternatives to SSB: The average number of days per week (= 6 days) in which children chose a low‐fat and low‐sugar healthy drink (defined as skim milk, 1% or 2% low‐fat white milk, 100% fruit juice, or water) for lunch, assessed by trained observers on 3 days each week during baseline and continuously throughout the 3‐month intervention phase Anthropometric measures: Assessed in the study but not included in this review due to confounding by non‐beverage‐specific intervention components Adverse outcomes: None reported Other outcomes: None included in this review
Context and implementation	Setting: Elementary schools Sector: Education Country: USA Year(s) when implemented: N/R Mode of implementation: Pilot trial by researchers Level of implementation: Setting‐based intervention
Declarations	COI: N/R (the study's primary report does not contain a COI section) Funding: "This research was supported by grants from Penn State University. We thank the student research team members from Psychology 494 of Penn State Schuylkill for supply preparation, data collection, and data processing. For their support, we also express appreciation to the school board, superintendent, school staff, and parent volunteers of Schuylkill Haven Area Elementary Center, with special thanks to Rene Reese, Nurse Cheryl Wagner, Melanie Wade, Wally Haus, and Alberta Hudson" Trial registration: N/R Protocol availability: N/R
Notes	The study's published report shows data on healthy beverages (defined as skim milk, 1% or 2% low‐fat white milk, 100% fruit juice, or water) only. We contacted the corresponding author, who informed us that the share of children not consuming any beverage for lunch was negligible (approx. 1%), and that it can therefore be assumed that close to all children who did not select a healthy beverage selected 1 defined as unhealthy (including sugar‐sweetened milk, whole plain milk, soda, and artificial fruit drinks). She confirmed that sugar‐sweetened milk was by far the most popular beverage at baseline. We therefore included the study as a study of an intervention targeting sugar‐sweetened beverages
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	We contacted the study's corresponding author for additional information on the randomisation procedure, which is not described in detail in the study’s published report. We received the answer that participants were listed in alphabetical order and then randomly assigned to the IG and CG with a table of random numbers from a statistics textbook, with odd numbers assigned to 1 group, and even numbers assigned to the other group
Allocation concealment (selection bias)	Low risk	See explanation above
Similarity of baseline outcome measurements (selection bias)	Low risk	The difference in HDRINK between the control and intervention groups at baseline seems to have been minimal (see figure 1b of the study's primary report)
Similarity of other baseline characteristics (selection and performance bias)	Unclear risk	Participant characteristics other than baseline outcome measurements are not reported for the IG and CG separately, and may have been different between groups if randomisation was not perfect. Differences in baseline provider characteristics are unlikely, as the 2 interventions (the KCP and the control intervention) were delivered by the same team of research assistants and parent volunteers
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Attrition was substantial (32%) and is not reported separately for the CG and IG. Analyses are per protocol. Only healthy beverage selection was recorded directly, and effect estimates for unhealthy beverage selection are based on the assumption that the share of children not having any beverage for lunch was approximately 1% and therefore negligible (this information was provided to us by the study’s corresponding author)
Blinding (performance and detection bias) Objective outcomes	Low risk	Outcomes were assessed blindly. Quote: "Lunch observers were kept blind as to children’s group assignments as they completed their lunchtime datasheets, which were then handed over to other research assistants who walked down the lunch tables, flipped over each child’s nametag to read the small print showing each child’s group assignment, and punched stars into the child’s nametag according to how many of the ‘Good Citizenship Behaviors’ or ‘Good Health Behaviors’ were recorded on the datasheet"
Contamination (performance bias)	High risk	Contamination is likely, and would have reduced observed effect sizes. Quote: "As in previous one month KCP applications (...), the present study found that the KCP‐targeted behaviors (FVFIRST, HDRINK, and EXERCISE) showed improvements lasting throughout the three‐month application, both for children who received the program directly (the KCP group), and for children who only observed it being applied to their classmates (the control group"
Selective reporting (reporting bias)	Low risk	All outcomes mentioned in the Methods section are reported in the Results section
Other bias	Low risk	No other concerns