Table 4.

Mediating Effects of Attribute Variability and Network Size: Results from Three-Level Random Effects Meta-Analyses of Correlations¹ Between Friends

	Original Relationship Between Grade & Similarity	Reduction in Relationship Due to Controlling for Potential Mediators
Attribute		Total		Attribute Variability Only		Size of Network Only		Shared
Demographic	$\tilde{\mathit{b}}$	Amount Decr. $\tilde{\mathit{b}}$	Percent Decr. $\tilde{\mathit{b}}$	Amount Decr. $\tilde{\mathit{b}}$	Percent Decr. $\tilde{\mathit{b}}$	Amount Decr. $\tilde{\mathit{b}}$	Percent Decr. $\tilde{\mathit{b}}$	Amount Decr. $\tilde{\mathit{b}}$	Percent Decr. $\tilde{\mathit{b}}$
Gender	0.028	0.000	−1.1%	0.000	−0.1%	0.000	−0.9%	0.000	−0.2%
Race	0.015	0.005	35.1%	0.002	14.6%	0.002	13.1%	0.001	7.5%
Family Structure	0.008	0.003	43.7%	0.000	5.3%	0.002	28.4%	0.001	10.0%
Orientations to Institutions
Family Relations	0.008	0.003	36.4%	0.003	33.0%	0.000	0.3%	0.000	3.0%
School Grades	0.025	0.009	35.8%	0.005	18.5%	0.004	15.5%	0.000	1.9%
School Bonds	0.011	0.005	39.6%	0.003	29.0%	0.001	9.5%	0.000	1.1%
Religious Participation	0.012	0.002	13.1%	−0.001	−11.0%	0.003	25.9%	0.000	−1.8%
Problem Behaviors
Delinquency	0.012	0.003	22.6%	0.001	11.7%	−0.001	−4.8%	0.002	15.7%
Drinking	0.032	0.023	73.1%	0.023	71.3%	0.000	0.8%	0.000	1.1%
Cigarettes2	0.025	0.013	50.6%	0.007	28.4%	0.000	0.1%	0.006	22.0%
Marijuana2	0.028	0.017	58.8%	0.010	35.2%	0.000	0.3%	0.007	23.3%

¹Moran’s I adjusted for bias dependent on sample size, −1 / (N – 1).

²Waves 3–7

$\tilde{\mathit{b}}$ = Osgood et al. (1996) index of strength of relationship for curvilinear relationships, in a metric comparable to an unstandardized regression coefficient.