Table 1 A description of included primary and secondary outcomes
Name outcome variable | Description |
|---|---|
Primary outcomes | |
Total sedentary behaviour time | Sum of ‘total screen-viewing time’ (see secondary outcomes section below), ‘homework time’, and ‘out-of-campus learning time’. |
Homework time | Average hours spent per day doing homework, reading, and writing after school in the past week. |
Out-of-campus learning time | Average hours spent per day in fee-paying tutoring classes (such as English, math, and writing) in the past week. |
Electronic device use time (main estimator of online game time [estimand*]) | Average hours and minutes spent per day using mobile phones, handheld game consoles, and tablets in the past week. |
Secondary outcomes | |
Total screen-viewing time (alternative estimator of online game time [estimand*]) | Sum of ‘electronic device use time’ (see primary outcome section above), ‘TV/video game use time’ and ‘computer use time’. ‘TV/video game use time’: Children were asked to report the number of hours per day spent watching TV (including use of game consoles such as the X-BOX) in the past week. ‘Computer-use time’: Children were asked to report the number of hours per day spent using computers in the past week. |
Internet use time | Number of hours per day spent being “online” in the past week. |
Meeting screen-viewing time recommendations | Engaging in screen-related activities less than 2 h per day as indicated by the American Academy of Paediatrics guidelines21. |
Meeting regulatory requirement on homework time | Spending less than 60 min per day doing homework for primary-school children and 90 min per day for secondary-school children, as required by the national regulation. |