Check whether sleep, homework and getting outdoors are being squeezed out before you fix on how long a child plays

Moderate value
Evidence B
Saves time
For: Child aged 3–18
Free
Takes minutes
Some willpower

In plain words

Only about two or three people in every hundred really meet the bar for “gaming disorder.” If the questionnaire's cutoff is set low and it is aimed at teenagers, the share comes out inflated. In real records from game companies, how much someone plays has almost no link to how good their mood is. Under the rules, minors may play only from 8 p.m. to 9 p.m. on Fridays, Saturdays, Sundays and public holidays.

Cost: Free. Once a week, notice what time the child goes to bed, whether homework gets handed in, and whether they get out of the house.
What you get: One meta-analysis pooled 53 studies from 17 countries with 226247 people. The prevalence of gaming disorder was 3.05% (95% CI 2.38–3.91, a range of plausible values). Counting only studies with stricter sampling, it was 1.96%. Results differed widely between studies, and 77% of the differences came from which questionnaire was used. A sample of teenagers, a low cutoff score and a small sample all push the rate up. Another study got data from 7 game companies and linked the actual playing time of 38935 players over six weeks with their own reports of well-being. It found almost no evidence that time played affects well-being. The National Press and Publication Administration (国家新闻出版署) requires game companies to give minors only 1 hour of service a day, between 20:00 and 21:00 on Fridays, Saturdays, Sundays and statutory holidays (nationwide / international, since 2021).
Notes: Graded B because the prevalence varies too much with the questionnaire, and the well-being study followed players for only six weeks. The most common cost of gaming is that it squeezes out sleep and outdoor time. For the written requirements on sleep, see §30.10 (sleep, homework, PE), for outdoors see §30.4 (2 hours outdoors every day), and for screen time see §30.5 (no more than 1 hour a day of non-study use). For top-ups and refunds, see §5.9 (a child spending money on top-ups and tips on a phone). If grades, sleep and relationships at home are all falling apart together and talking doesn't stop it, take the child to a psychiatry department or a child psychology department. Don't send the child to a locked-down “internet addiction school”; see §30.18 (internet addiction schools). The beneficiary is the child.
Evidence grade: B : Supported by research but without a precise number, or based on small or single studies.
Sources: Stevens MW, Dorstyn D, Delfabbro PH, King DL. (2021). Global prevalence of gaming disorder: A systematic review and meta-analysis. Australian and New Zealand Journal of Psychiatry, 55(6), 553–568. https://doi.org/10.1177/0004867420962851
Vuorre M, Johannes N, Magnusson K, Przybylski AK. (2022). Time spent playing video games is unlikely to impact well-being. Royal Society Open Science, 9(7), 220411. https://doi.org/10.1098/rsos.220411
国家新闻出版署 (2021). 关于进一步严格管理切实防止未成年人沉迷网络游戏的通知（国新出发〔2021〕14 号）. https://www.gov.cn/zhengce/zhengceku/2021-09/01/content_5634661.htm

Mentioned in

Don't send a child to a locked-down “internet addiction school” or “special training camp”: the law forbids using methods that harm body and mind to curb internet addiction, and children have been locked up to death

Translated from the Chinese original. Original book, section 30, tip 14. Content may be out of date and rules differ by place. When you actually deal with an agency, a doctor or a court, follow what local officials, doctors and lawyers tell you. Disclaimer