Table 1.
Summary of Growth Curve Analyses
| Intercept | Linear (Time) | Quadratic (Time2) | Cubic (Time3) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| β | SE | p | β | SE | p | β | SE | p | β | SE | p | |
| Growth Curve | ||||||||||||
| 1. Drinking Days1 | −1.103 | .123 | <.001 | −.082 | .014 | <.001 | ns | Ns | ns | ns | ns | ns |
| × Age | .002 | .013 | .896 | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| × Race | −.103 | .225 | .649 | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| × Gender | −.077 | .445 | .863 | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| 2. Heavy Drink Days2 | −1.647 | .148 | <.001 | −.179 | .040 | <.001 | .011 | .004 | .004 | ns | ns | ns |
| × Age | −.013 | .013 | .330 | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| × Race | −.168 | .300 | .577 | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| × Gender | −.349 | .474 | .466 | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| 3. WAI | 5.526 | .106 | <.001 | .239 | .049 | <.001 | −.033 | .010 | <.001 | .002 | .0006 | .007 |
| × Age | −.0005 | .008 | .945 | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| × Race | −.271 | .172 | .119 | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| × Gender | .314 | .192 | .107 | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Growth × Pretreatment Change | ||||||||||||
| 1. Drinking Days | −1.323 | .141 | <.001 | .029 | .092 | .754 | −.031 | .021 | .135 | .002 | .001 | .096 |
| × PreTx | 1.369 | .145 | <.001 | −.323 | .050 | <.001 | .067 | .011 | <.001 | −.004 | .001 | <.001 |
| × Age | .001 | .011 | .924 | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| × Gender | −.120 | .250 | .634 | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| × Race | .160 | .447 | .721 | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| 2. Heavy Drink Days | −1.971 | .167 | <.001 | −.028 | .125 | .821 | −.034 | .029 | .250 | .003 | .002 | .107 |
| × PreTx | 1.304 | .165 | <.001 | −.320 | .089 | <.001 | .095 | .018 | <.001 | −.006 | .001 | <.001 |
| × Age | −.024 | .009 | .011 | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| × Gender | −.123 | .303 | .687 | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| × Race | −.288 | .375 | .445 | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| 3. WAI | 5.526 | .105 | <.001 | .239 | .049 | <.001 | −.033 | .010 | <.001 | .002 | .0006 | .004 |
| × PreTx3 | −.111 | .134 | .408 | −.024 | .074 | .745 | .011 | .015 | .461 | −.0007 | .0009 | .455 |
| × Age | −.0006 | .008 | .944 | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| × Gender | −.285 | .169 | .098 | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| × Race | .307 | .191 | .113 | -- | -- | -- | -- | -- | -- | -- | -- | -- |
Note: PreTx = pretreatment change; percent change in drinking (number of drinking days) prior to first treatment session; Gender = 0 Female, 1 Male; Race = 0 Caucasian, 1 Minority. β = unstandardized estimate; SE = standard error; ns = non-significant term trimmed from final model. Growth parameters were modeled as fixed and centered at session 1.
Model comparison test (Deviance statistic based on Laplace estimation) for final model versus full model confirmed that the addition of quadratic and cubic effects did not improve model fit; χ2(2) = 1.993, p >.500.
Model comparison test (Deviance statistic based on Laplace estimation) for final model versus full model confirmed that the addition of the cubic effect did not improve model fit, supporting the trimmed (final) model; χ2(2) = 1.993, p >.500.; χ2(1) = 0.075, p >.500.
Percent change in number of drinking days was entered as the pretreatment change variable.