Table 5.

Generalized estimating equation analysis of the effectiveness of the intervention for improving life skills for preventing substance use (N=1065). Model: Y=β0+β1(group)+β2(time)+β3(group×time).

Parameter	Estimate（β）	SE	P value	95% CI
Intercept	.825	0.0084	<.001	0.808 to 0.841
Group (experimental versus controla)	–.022	0.0132	.09	–0.048 to 0.004
Time (follow-up versus baselinea)	.011	0.0069	.13	–0.003 to 0.024
Group×time	.006	0.0111	.61	–0.016 to 0.027

^aReference group.