TABLE 3.
Friendship Network and Past Month Marijuana Use Dynamics: Interaction Between Friend Influence and Friendship Reciprocity
| Model parameter | School 1 |
School 2 |
||||
|---|---|---|---|---|---|---|
| P.E. | SE |
p value |
P.E. | SE |
p value |
|
| Friendship network dynamics | ||||||
| Rate parameter | 8.52 | 0.71 | - | 15.33 | 0.99 | - |
| Effects of network structure | ||||||
| Outdegree | −4.89 | 0.19 | .000 | −2.96 | 0.18 | .000 |
| Reciprocity | 3.11 | 0.11 | .000 | 2.18 | 0.12 | .000 |
| Transitive triplets | 0.70 | 0.08 | .000 | 0.20 | 0.08 | .016 |
| 3-cycles | −1.09 | 0.13 | .000 | −0.12 | 0.17 | .484 |
| Transitive ties | 1.30 | 0.15 | .000 | 1.25 | 0.11 | .000 |
| Outdegree popularity (sqrt) | −0.49 | 0.08 | .000 | −0.31 | 0.10 | .003 |
| Effects of covariates | ||||||
| Gender ego | 0.11 | 0.06 | .070 | 0.04 | 0.06 | .487 |
| Gender alter | 0.03 | 0.05 | .553 | 0.03 | 0.05 | .549 |
| Same gender | 0.32 | 0.06 | .000 | 0.09 | 0.05 | .089 |
| Same race/ethnicity | 1.17 | 0.07 | .000 | - | ||
| Grade ego | −0.14 | 0.06 | .021 | −0.08 | 0.07 | .233 |
| Grade alter | 0.19 | 0.06 | .002 | 0.11 | 0.07 | .091 |
| Same grade | 0.41 | 0.05 | .000 | 0.35 | 0.06 | .000 |
| Parent education ego | −0.07 | 0.03 | .012 | NS | ||
| Parent education alter | 0.08 | 0.03 | .004 | NS | ||
| Parent education sq. alter | 0.01 | 0.03 | .684 | NS | ||
| Similar parent education | 0.20 | 0.11 | .078 | NS | ||
| Rate limited nominations | −0.76 | 0.31 | .013 | −0.24 | 0.54 | .664 |
| Limited nominations ego | 0.24 | 0.19 | .196 | 0.49 | 0.24 | .040 |
| Effects of marijuana use | ||||||
| Marijuana use ego | −0.01 | 0.08 | .860 | 0.10 | 0.06 | .102 |
| Marijuana use alter | −0.19 | 0.43 | .652 | 0.49 | 0.24 | .040 |
| Marijuana use sq. alter | 0.14 | 0.14 | .314 | 0.41 | 0.31 | .195 |
| Similar marijuana use | 1.53 | 0.52 | .003 | 1.03 | 0.22 | .000 |
| Marijuana use dynamics | ||||||
| Rate | 4.32 | 0.80 | - | 4.04 | 0.95 | - |
| Shape effects | ||||||
| Linear shape | −1.70 | 0.12 | .000 | −1.41 | 0.14 | .000 |
| Quadratic shape | 0.38 | 0.04 | .000 | 0.38 | 0.05 | .000 |
| Effects of individual covariates | ||||||
| Male | NS | NS | ||||
| Grade | NS | 0.35 | 0.16 | .025 | ||
| Race/ethnicity | NS | NS | ||||
| Parent education | −0.13 | 0.06 | .035 | NS | ||
| Effects of friends | ||||||
| Friends’ marijuanause (influence) | NS | NS | ||||
| Friends’ marijuanause (influence) * Friendship reciprocity | 1.14 | 0.52 | .028 | 0.51 | 0.45 | .254 |
Note. P.E. = parameter estimate. SE = standard error. NS = not statistically significant. Parameters in bold are significant at the p < .05 level. All control effects were score tested during the forward model specification, and only effects found to be marginally or statistically significant (p < .1) were retained and estimated in the models. Effects listed as non-significant were found to be non-significant predictors in this forward selection process and so were not estimated in the final model.