Table 2.

Growth Trajectory Analysis (6^th 12^th grades) for Iowa and Pennsylvania sites, 2002–2010

Outcome	Condition Main Effect F(1,12) (p)	Condition* Risk F(1,12) (p)	Condition* Time (Linear) F(1,72) (p)	Condition* Risk* Time (Linear) F(1,78) (p)
Lifetime Illicit Substance Use	16.72 (.001)	16.69 (.001)	51.90 (.001)	14.22 (.001)
Current Use
Past Month Drunkenness	1.47 (.124)	2.80 (.059)	2.32 (.066)	1.76 (.094)
Past Month Cigarettes	1.71 (.107)	3.64 (.040)	3.95 (.025)	0.46 (.250)
Past Year Marijuana	11.82 (.002)	14.95 (.001)	3.10 (.041)	3.87 (.026)
Past Year Driving after Drinking*	1.01 (.166)	1.58 (.116)	N/A	N/A
Past Year Inhalants	4.21 (.031)	1.95 (.093)	0.16 (.345)	2.18 (.071)
Past Year Methamphetamine	9.91 (.004)	1.09 (.158)	6.44 (.006)	1.53 (.110)
Frequency of Use
Drunkenness	2.32 (.076)	4.09 (.032)	2.98 (.044)	1.62 (.103)
Driving after Drinking*	2.34 (.076)	2.92 (.056)	N/A	N/A
Marijuana	12.03 (.002)	9.36 (.004)	10.08 (.001)	3.82 (.027)

^*Measure only available at 11^th and 12^th grades, linear growth effects not calculated.

Reported p-values are for 1-tailed tests; 2-tailed significance levels can be calculated by doubling the reported 1-tailed values.