USC / Stanford — Adolescents’ Experiences of Online Harms by Platform

“Adolescents’ Experiences of Online Harms by Platform”

Lee, Lim, Liu, et al., JAMA Pediatrics; USC and Stanford study. doi:10.1001/jamapediatrics.2026.4692.

“US adolescents aged 13 to 17 years”

“Published online September 18, 2026.”

Publication year 2026; fieldwork February–December 2025.

“conducted from February to December 2025”

“The weighted sample included 472 adolescents”

Weighted N=472. Supplement 1 describes 509 eligible respondents (pp.2–3), while its unweighted tables show 505 (p.6); the sources do not reconcile these counts. Platform-specific weighted user bases vary.

“US adolescents aged 13 to 17 years”

“through the probability-based Understanding America Study panel”

Probability-based recruitment via the USC Understanding America Study (UAS) panel; weighted to be nationally representative of US adolescents aged 13-17.

“In the past 4 weeks, whether online or in person, has anyone done any of these things to you?…” “Insulted or disrespected you”“Contacted you in an inappropriate way”“Damaged your reputation”“Threatened you”“Excluded you or left you out”

Q028 — direct harassment victimization (one combined Yes/No item). Follow-ups ask whether the respondent felt threatened and whether it was repeated; Q030 is the separate witnessing version.

“In the past 4 weeks, whether online or in person, have you seen someone harm themselves, or threaten to do so?”

Q036 — exposure to self-harm (Yes/No). Q037 is a companion: 'have you seen anyone encourage someone to harm themselves?'.

“In the past 4 weeks, whether online or in person, have you seen any violent, bloody, or disturbing images that”“bothered you?”

Q035 measures exposure to violent, bloody, or disturbing images that bothered the respondent, using Yes/No responses.

“In the past 4 weeks, whether online or in person, has anyone used your photos in an inappropriate way?…” “Was the inappropriate use of your photos sexually explicit or involve nudity?”

Q034A is asked after Yes to the broad photo-misuse screen Q034. The context follow-up also refers to broad photo misuse; its generic Yes routing does not specify Q034 versus Q034A. Published photo-misuse results do not isolate sexually explicit or nude imagery.

“How often do you feel that your use of technology gets in the way of your sleep?”

Q047 asks about sleep interference using Never/Rarely/Sometimes/Often. Q048 asks which services contribute, only when Q047 is Sometimes or Often. Q047 itself does not specify a recall window.

“In the past 4 weeks, whether online or in person, have you received unwanted sexual advances?”

Q031 asks about unwanted sexual advances; Q032 separately asks about an unwanted conversation. Both use Yes/No responses. Q026 concerns seeing unwanted sexual images, a related exposure measure that does not necessarily establish direct contact.

“In the past 4 weeks, whether online or in person, has anyone done any of these things to you?…” “Insulted or disrespected you”

Q028 uses an online/in-person stem and includes 'In-person / offline' in its context follow-up. This documents offline measurement independently of published-result availability.

“In the past 4 weeks, whether online or in person, have you seen someone harm themselves, or threaten to do so?”

Q036 uses an online/in-person stem and its context follow-up includes 'In-person / offline', documenting offline measurement. Q037 separately asks about encouragement of self-harm.

“In the past 4 weeks, whether online or in person, have you seen any violent, bloody, or disturbing images”

Q035 uses an online/in-person stem and its context follow-up includes 'In-person / offline', documenting offline measurement.

“In the past 4 weeks, whether online or in person, has anyone used your photos in an inappropriate way?…” “Was the inappropriate use of your photos sexually explicit or involve nudity?”Response options: In-person / offline

The Q034/Q034A context list includes In-person / offline. Its generic Yes routing does not specify whether it follows broad photo misuse or the sexually explicit/nudity follow-up.

“In the past 4 weeks, whether online or in person, have you received unwanted sexual advances?”

Same Q031 online/offline unified stem; follow-up includes 'In-person / offline'.

“In which contexts/online services did you experience something that affected you negatively?”

The harm-specific context rosters include 16 named apps. Email, Text Messaging, Online Gaming, Any dating App, catch-all choices, an unlabeled choice, and offline contexts are excluded from the app count. Table 2 publishes results for 8 of the named apps; unavailable or suppressed results do not remove documented measurement coverage.

“Among adolescents who used each platform in the past 4 wk”

The published app-level columns on PDF pp.5–6 cover 8 named apps: Snapchat, YouTube, TikTok, Facebook, Instagram, Pinterest, Discord, and FaceTime. Online gaming, Text messaging, and Email are categories or channels rather than named apps. Additional weighted crosstabs are supplied separately; no offline sleep question was asked.

“In which contexts/online services did you experience being a target of harassment”

Q028 asks about direct harassment and is followed by a multiple-select context list with 16 named apps. Generic channels, activities and catch-all options are excluded from the app count.

“In which contexts/online services have you seen someone harm themselves, or threaten to do so?”

Q036 follow-up and Q037's encouragement-of-self-harm follow-up cover the 16 branded apps in the context roster. Published numerical-result availability is recorded separately.

“In which contexts/online services have you seen any violent, bloody, or disturbing images that bothered you?”

Q035 follow-up covers the 16 branded apps in the context roster. Published numerical-result availability is recorded separately.

“Was the inappropriate use of your photos sexually explicit or involve nudity?”“In which contexts/online services has anyone used your photos in an inappropriate way?”

Q034A identifies sexually explicit or nude photo misuse. The 16-app context follow-up refers to broad photo misuse, and its generic Yes routing does not explicitly identify Q034 versus Q034A. This does not establish an NCII-specific app estimate.

“Which of the below online services get in the way of your sleep?”

Q048 — asked only when Q047 = Sometimes/Often; covers the 16 branded apps in the service roster. Generic channels, activities, and catch-all options are excluded. No separate offline sleep measure is asked.

“In which contexts/online services have you received unwanted sexual advances?”

Q031 and Q032 have harm-specific context follow-ups, each with 16 named apps plus generic online and offline contexts.