TABLE 3.
Fundamental and advanced MI skills, and MI inconsistent strategies adherence and competence ratings by treatment condition, program site, and therapist (nested in condition): univariate and multivariate ANOVAs.
| ANOVA | MIA | CAU | Treatment Condition | Program Site | Treatment by Site | Therapist (in condition) |
|---|---|---|---|---|---|---|
| Univariate | ||||||
| Fundamental MI Skills | ||||||
| Adherence | M = 4.43 | 2.83 | F = 125.98 | 9.64 | 1.34 | 9.52 |
| SD = 1.03 | 1.13 | df = 1,232 | 3,232 | 3,232 | 2,232 | |
| N = 154 | 150 | p < .001 | p < .001 | p=.26 | p < .001 | |
| Competence | M = 4.84 | 4.05 | F = 22.00 | 10.93 | 1.70 | 9.91 |
| SD = .79 | .83 | df = 1,196 | 3,196 | 3,196 | 2,196 | |
| N =154 | 145 | p < .001 | p < .001 | p = .39 | p < .001 | |
| Advanced MI Skills | ||||||
| Adherence | M = 3.32 | 1.90 | F = 196.96 | 6.92 | 5.47 | 1.74 |
| SD = .95 | .60 | df = 1,232 | 3,232 | 3,232 | 2,232 | |
| N = 154 | 150 | p < .001 | p < .001 | p < .001 | p =.18 | |
| Competence | M = 4.69 | 4.05 | F = 14.80 | 7.93 | 5.66 | 7.84 |
| SD = .75 | .88 | df = 1,196 | 3,196 | 3,196 | 2,196 | |
| N = 153 | 143 | p < .001 | p < .001 | p = .01 | p < .001 | |
| MI Inconsistent Strategies | ||||||
| Adherence | M = 2.26 | 2.52 | F = 3.43 | 8.33 | 1.58 | 1.14 |
| SD = 1.26 | 1.35 | df =1,232 | 3,232 | 3,232 | 2,232 | |
| N = 154 | 150 | p = .07 | p < .001 | p = .20 | p = .32 | |
| Competence | M = 4.19 | 4.00 | F = 1.99 | 3.29 | 1.66 | 2.41 |
| SD = .75 | .76 | df = 1,196 | 3,196 | 3,196 | 2,196 | |
| N = 126 | 134 | p = .06 | p=.11 | p=.38 | p=.11 | |
| Multivariate | ||||||
| Adherence | i = .48 | .19 | .09 | .09 | ||
| F = 70.62 | 18.39 | 8.00 | 8.03 | |||
| df = 3,230 | 3,232 | 3,232 | 3,231 | |||
| p < .001 | p < .001 | p < .001 | p < .001 | |||
| Competence | i = .18 | .09 | .06 | .09 | ||
| F = 14.60 | 6.70 | 4.28 | 6.31 | |||
| df = 3,194 | 3,196 | 3,196 | 3,195 | |||
| p < .001 | p < .001 | p < .001 | p < .001 |
Note: For univariate ANOVAs, p-values ≤.0084 (Bonferroni-correction of .05/6) are significant. MIA = motivational interviewing assessment; CAU =counseling-as-usual. Univariate ANOVAs (for tests of adherence and competence differences) and multivariate ANOVAs (for deriving Roy's theta) included two MIA and CAU therapists from each site who had five or more unique client sessions that had been independently rated (MI =242/315). Roy's theta θ provides an estimate of the amount of variance accounted for by each effect involving adherence and competence ratings, with each set of ratings entered simultaneously in separate multivariate models (21).