{
  "study_id": "NCT07513337",
  "agent": "baseline",
  "run": 3,
  "p_primary_hypothesis_supported": 0.33,
  "effect_direction": "null",
  "effect_size_90pct_interval": {"low": -0.10, "high": 0.20, "metric": "Mean difference in one-time-use harm perception, 0-4 scale, labelled/claimed ads vs the corresponding no-label/no-claim level (positive = lower perceived harm)"},
  "moderator_prediction": "Inexperienced users respond more: their harm perceptions are less anchored by personal experience, so label/claim cues (which add product legitimacy and specificity) shift ratings more; experienced users already rate one-time-use risk near floor.",
  "claim_ids_used": [],
  "rationale": "Large online factorial (n=3035, ~250/arm); main-effect contrasts pool ~2000 vs ~760-1000, giving power to detect ~0.12-0.15 point differences (SD ~1.1). But single-exposure ad-feature manipulations typically move perceptions only slightly, and one-time-use harm for cannabis is already rated low among users (floor effects). Strain labels are familiar and not obviously risk-reducing; a sedating claim may even raise perceived risk, offsetting any energizing-claim effect in the pooled 'any claim' contrast. Two shots at significance (either main effect) raises odds somewhat, and immediate self-report outcomes move readily per persuasion literature. Net: modestly below the ~44% pre-registered base rate."
}