Table 1 Example of items, source and test–retest reliability test results of potential determinants included in the study
Variables with example items asked | Response categories | ICC and/ or percentage agreement** |
|---|---|---|
Self-efficacy*; “e.g. I find it easy to choose a healthy snack when I eat in-between meals (e.g. fruit or reduced-fat yoghurt) [31]” | 5 point likert-type scale ranging from 1(strongly disagree) to 5(strongly agree) | 0.61 |
Maternal and paternal norms*; “My mother/father thinks I should eat healthily; My mother/father is a healthy eater [32].” | 5 point likert scale ranging from 1(strongly disagree) to 5(strongly agree) | 0.4- 0.7 for maternal norms; 0.35–0.36 (70–80%) for paternal norms |
Parental rules regarding adolescent SSB intake; “my parents have clear rules for how much sugar-sweetened beverages (e.g. fizzy drinks, fruit squash, cordials etc.) I can drink [33].” | Answer categories ranging from 1(not at all) to 5(very) | 0.67 |
Perceived accessibility of SSB at home*; “e.g. at home, we usually have soft drinks for dinner at the weekend [33]” | 5 point likert-type scale ranging from 1(strongly disagree) to 5(strongly agree) | 0.67 |
parental modelling for SSB intake*; “ my mother/mother drinks fizzy drinks with added sugar several times a week [34]. “ | 5 point likert-type scale ranging from 1(strongly disagree) to 5(strongly agree) | 0.66-maternal modelling 0.81-paternal modelling |
Food purchasing behaviours;” How often do you usually purchase food/drinks in shops (grocery shop, kiosk, gas station) close to your school or your neighbourhood? [35]” | A categorical response with 7 response categories (i.e. never, every other week, once a week, twice a week, 3 times a week, 4–5 times a week, 6 times or more) | 0.69 |
Perceived neighbourhood accessibility of SSB; “ There is a large variety of sugar-sweetened drinks that I like available close to my school/neighbourhood where I purchase food/drink [35].” | 5 point likert-type scale ranging from 1(strongly disagree) to 5(strongly agree) | 0.59 |
Perceived neighbourhood accessibility of food outlets (grocery stores, kiosks/gas stations, fast food places);”e.g.There are grocery stores (e.g. Kiwi, Rema 1000), within easy walking distance from my home [36].” | 5 point likert-type scale ranging from 1(strongly disagree) to 5(strongly agree) | - |
Perceived travel time to the nearest stores;” e.g.about how long would it take you to walk from your home to the nearest grocery store….etc.” | categorical, with 6 response categories (i.e.1–5 min, 6–10 min, 11–20 min, 21–30 min, 31 min or more, I don’t know | travel time to kiosk/ gas stations(0.53), grocery stores(0.65), fruit and vegetable store(0.64), and fast-food outlets (0.67) |
Perceived price of food items;”e.g. It is cheaper to buy soft drinks or snacks (e.g. biscuits or chips) than buying fruit and vegetables.” | 5 point likert-type scale ranging from 1(strongly disagree) to 5(strongly agree) | 0.75 |