A discrete time survival analysis model was ran using Mplus Version 7.1 (Muthén and Muthén, 1998–2013). The proportional hazard assumption was not violated for the polygenic score (−2LL=7.42, df=9, p=.59), which suggest that the relationship between the polygenic score and first marijuana use remained constant across grades. Similarly, the proportional hazard assumption was not violated for the population stratification variable (−2LL=8.46, df=9, p=.49). Intervention was not a significant predictor of survival to first marijuana use (est.= −.191, S.E.=0.168, p=.257). The polygenic score was a marginally significant predictor of risk of first marijuana use (est.=−0.159, S.E.=.081, p=.050).
