CHAMGAP
VERIFIEDPassed the Codex final verification and publication gate. Evidence-verification cutoff: 2026-08-05. AI was used for research and drafting; the existence of all 2 cited sources was verified at the original page, followed by blind grading, adversarial audit, and build validation. Methodology v1.0.
Verdict No. 2255 · Search date 2026-08-05 · Methodology v1.0

Violent video-game exposure,
does it really help with Increased long-term aggressive behavior?

30-Second Summary
C
Evidence Grade C · 46 · Safety caution
The average longitudinal association with later aggression was positive but tiny and near zero in better-designed studies
A specific game should not be presumed to cause violence or used to stigmatize a young person. Age ratings, sleep or functional disruption, online harassment, and actual aggressive behavior should be assessed separately.
What the
research shows
The grade is C. A preregistered meta-analysis of 28 independent longitudinal samples and about 21,000 young people found an adjusted overall association of r=0.059, 95% CI 0.034-0.084. This explains 0.348% of aggression variance. Ten higher-practice samples gave r=0.012, -0.010 to 0.034, indistinguishable from zero. Another meta-analysis reported beta=0.106, 0.078-0.134, also a small effect.
What the
ads claim
These results do not show that a young person who plays a violent game will later commit violent crime. The evidence mainly concerns small longitudinal associations between questionnaire-based game content and aggressive behavior, not hard events such as crime or hospitalization. Tiny is not the same as exactly zero.
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Useful facts when choosing a product

  • Most included studies measured game time and violent content by adolescent self-report rather than objective play logs.
  • The preregistered overall r=0.059 explained 0.348% of aggression variance.
  • Ten higher-practice samples pooled to r=0.012, 95% CI -0.010 to 0.034.
  • Prescott's random-effects beta=0.106, 95% CI 0.078-0.134, pointed in the same direction but used a different estimand and study-selection approach, so it was not treated as direct replication.
ID

Chamgap Semantic Classification Code

Candidate index · review held

X.longitudinal-follow-up-of-adolescents-reported-exposure-to-violent-video-games.environmental.long-term-aggressive-behavior.increase.UNK

Behaviors, exposures and policies > Longitudinal follow-up of adolescents' reported exposure to violent video games > Environmental exposure > long-term aggressive behavior > Increase claim > Unknown

An automated migration candidate, not an issued permanent code; exact claim scope remains under review. This machine-generated migration candidate helps retrieval but is not a permanent assignment. The original verdict ID and URL remain authoritative.

Download semantic index (JSON) · Codebook v1

Gap Measurement · Verdict 2255 · C 46
What advertising claims
What independent, higher-quality research supports
△ GAP
01

What the research actually shows

Drummond included longitudinal or prospective studies with at least three weeks between waves, violent game content as the predictor, and behavioral aggression rather than thoughts or feelings as the outcome. Twenty-eight independent samples were selected, prioritizing standardized coefficients with the most relevant adjustment for sex, baseline aggression, family, mental health, and peers. The plan was preregistered at OSF gbx4w and data and code were shared. Overall I-squared was 63.96%, which reflects magnitude heterogeneity rather than automatic directional conflict. Marsden Fund public support and no competing interests were verified, but industry funding across every primary study was not.

02

Why this is classified as C (46)

Preregistration and a positive longitudinal pooled association are strengths, but magnitude was tiny and self-reported exposure, inconsistent outcome standardization, and design-sensitive estimates create multiple limitations, giving C with 46 points.

Counterpoint. C does not mean a medium danger level. It grades the evidence for a long-term increase claim; the measured average association itself was very small.

Rejudgment record. Cross-check applied — Effect-size and estimand comparison between a preregistered longitudinal meta-analysis and the opposing synthesis, including self-reported exposure and best-practice subsets

Stored scoring profile
EndpointPSymptom or function itself is the target - including patient reports and performance tests
ReplicationR1Single confirmatory trial
IndependenceI1Mixed funding sources
Effect sizeE~Statistically positive but below the threshold

Stored derived and displayed grades match; this is not a current recalculation or validity check (C).

Sub-claim grades by effect

This ingredient is marketed for several effects. A single overall grade blends strong and weak claims together, so each effect is graded separately here. The overall grade reflects the strongest disconfirming or core claim.

Effect (sub-claim)GradeBasis
A small longitudinal association with later aggressionCOverall r was 0.059, explaining 0.348% of variance.
Increased long-term aggression in higher-practice studiesDThe confidence interval around r=0.012 crossed zero.
Increased violent crime?The meta-analysis mainly assessed questionnaire-based behavioral aggression, not established crime events.

Cross-check — AI research and Codex final gate

AI was used for research and drafting. Blind grading, adversarial audit, and the methodology boundary rules were then reapplied before Codex performed the final evidence, grade, copy, and build checks. If a grade cannot be narrowed, both evidence positions and their reasons are published.
03

Evidence Table

StudyDesignSampleFundingEndpointResultWeight
Drummond, Sauer, and Ferguson 2020Preregistered meta-analysis of longitudinal studies28 independent samples and approximately 21,000 youthPublic support from the New Zealand Marsden FundLater behavioral aggression adjusted for baseline aggression and other covariatesOverall r=0.059, 95% CI 0.034-0.084, I-squared 63.96%; higher-practice r=0.012, -0.010 to 0.034Preregistered longitudinal evidence with tiny magnitude and measurement limitations
Prescott, Sargent, and Hull 2018Meta-analysis of prospective studies24 studies and more than 17,000 participantsFunding across all included primary studies was not establishedPhysical aggression after violent video-game exposureRandom-effects beta=0.106, 95% CI 0.078-0.134Positive direction, but different estimand and study selection prevent treatment as direct replication
§

Receipt — 2 References

All 2 cited sources were verified for existence at the original page (as of 2026-08-05).

Drummond A, Sauer JD, Ferguson CJ. R Soc Open Sci. 2020;7(7):200373. PMID: 32874632. DOI: 10.1098/rsos.200373.
checked
Prescott AT, Sargent JD, Hull JG. Proc Natl Acad Sci U S A. 2018;115(40):9882-9888. PMID: 30275306. DOI: 10.1073/pnas.1611617114.
checked
Research and draft: AI used · Cross-check: blind grading and adversarial audit
Final verification and publication gate: Codex · Evidence date: 2026-08-05 · Corrections: none

Cite this verdict

Violent video-game exposure x long-term youth aggression Evidence Grade C card
[Chamgap] Violent video-game exposure x long-term youth aggression — Evidence Grade C·46. 2 cited sources checked. Source: https://chamgap.com/en/verdicts/general/violent-video-games-youth-long-term-aggression/ · CC BY 4.0

CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.

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