Table 4.

Predictive Validity: Partial Correlations between Diffusion Measures and Substance Use Diffusion

	Traditional Analytic Measures
	1 Year Follow-up		2 Year Follow-up
	Pretest	Posttest	Pretest	Posttest
Participation Rate	0.26	0.20	0.45**	0.43**
Representativeness
Demographic Representativeness
Gender	−0.30†	−0.17	0.19	0.09
Free Lunch	0.19	−0.10	−0.14	−0.17
Behavioral Representativeness
Grades	−0.04	0.35*	−0.26	0.36*
Delinquency	−0.03	0.13	0.05	0.05
Substance Use Attitudes	0.21	−0.13	0.17	−0.37*
Average Representativeness	−0.02	−0.03	−0.06	0.16

	SNA Measures
	1 Year Follow-up		2 Year Follow-up
	Pretest	Posttest	Pretest	Posttest
Social Integration
Connectivity
Structural Cohesion	−0.08	0.35*	0.30†	0.57***
Social Distance	−0.20	0.34†	0.15	0.28
Clustering
Segregation Index	0.16	−0.20	−0.13	−0.36*
Transitivity Ratio	−0.09	−0.31†	−0.22	−0.53***
Hierarchy
Indegree Centralization	−0.31†	−0.46**	−0.25	−0.09
Betweenness Centralization	−0.26	0.05	0.20	0.04
Location of the intervention participants
Distribution of Participants across the Network
Prop. of Groups with 1+ Part.	0.01	0.13	0.19	0.25
Prop. within 2 Steps of a Part.	−0.03	0.13	0.36*	0.45**
Participants’ Relative Status
Indegree	0.09	0.09	−0.06	0.02
Betweenness	0.04	0.09	−0.44*	0.12
Global Network Index	0.36*	0.49**	0.09	0.35*

Note. Prop = proportion; Part = Intervention participant. Substance use diffusion was defined as −1*(absolute difference in substance use between participants and non-participants), such that higher scores = higher diffusion. All analyses partial out network size and survey participation rate at either the 1-year or 2-year follow-up and substance use representativeness at either pretest or posttest. All analyses except for participation rate also controlled for SFP10-14 participation rate.

^†p < .10.

^*p < .05.

^**p < .01.

^***p < .001.