Table 2.
Mixture Models for Heavy Alcohol Use, for Smoking, and for Marijuana Use
AIC | BIC | Entropy | Vuong-Lo-Mendell-Rubin LRT (p-value) | |
---|---|---|---|---|
Heavy drinking (n = 31,939) | ||||
2 classesa | 305657.94 | 305833.74 | 0.94 | <0.001 |
3 classes | 300408.64 | 300617.93 | 0.83 | <0.001 |
4 classes | 289682.53 | 289925.31 | 0.90 | <0.001 |
Smoking (n = 31,952) | ||||
2 classes | 295847.47 | 295981.42 | 0.95 | <0.001 |
3 classes | 283840.21 | 283999.28 | 0.99 | <0.001 |
4 classes | 275359.47 | 275543.65 | 0.94 | <0.001 |
5 classes | 266864.32 | 267073.62 | 0.94 | <0.001 |
6 classesc | 265235.94 | 265235.94 | 0.70 | 0.49 |
Marijuana use (n = 31,961) | ||||
2 classes | 306752.76 | 306928.58 | 0.99 | <0.001 |
3 classes | 290694.36 | 290903.67 | 0.97 | <0.001 |
4 classes | 275215.38 | 289160.32 | 0.97 | <0.001 |
5 classesb | 269909.77 | 270177.68 | 0.97 | <0.001 |
6 classesc | 266973.74 | 267283.52 | 0.69 | 0.50 |
LRT, likelihood ratio test.
This model had an improper solution (nonpositive definite residual covariance matrix) that could not be resolved. Although none of the growth factors had negative variances, it appears likely that the model which extracted 2 classes over-estimated the variance in the quadratic factor. However, given that it is an independence model against which to compare solutions with greater than 2 classes, we retain it in the Table for reference.
As this model had an improper solution (nonpositive definite residual covariance matrix), the Year 1 residual variance was constrained to zero.
This model had an improper solution (nonpositive definite first-order derivative matrix) that could not be resolved.