Table 2.

Summary of Results Across Interaction Models

	12-Month Heavy Drinking Days	12-month Drug Use Days
Predictors	B (SE)	B (SE)
Among Full Available Sample
Treatment × Race/Ethnicity	−14.73 (1.25)**	2.92 (1.14)*
Treatment × Group Racial/Ethnic Composition	6.07 (1.79)**	−1.89 (1.35)
Among whites only
Treatment × Race/Ethnicity Match	−5.75 (1.29)**	−4.71 (1.97)**
Among Racial/Ethnic Minorities Only
Treatment × Race/Ethnicity Match	−5.90 (2.70)*	−0.42 (2.49)

Note.

^*p < .05;

^**p < .01.

B =unstandardized regression coefficient; SE = standard error. Race was coded 1 =white, 0 = racial/ethnic minority. Group Race Composition was coded 1= diverse race group, i.e., 50% or more ethnic/racial minorities in group, 0= non-diverse race/ethnicity group, i.e., less than 50% ethnic/racial minorities. Race/Ethnicity Match coded 1 = race/ethnicity match: race composition of group was match to participant’s own race, i.e., white participant in a group with more than 50% whites, or racial minority participant in a group with 50% or more racial minorities), 0 = race/ethnicity different: race composition of group was different from participant’s own race, i.e., white participant in group with 50% or more racial minorities, or racial minority participant in group with more than 50% whites. A total of 8 separate interaction models were conducted: 2 Treatment × Race/Ethnicity models (one for each of the two outcomes), 2 Treatment × Group Race/Ethnicity Composition models, and 2 Treatment × Race/Ethnicity Match models for whites, and 2 Treatment × Race/Ethnicity Match models for racial/ethnic minorities. Treatment was coded 1 =received MBRP, 0 = received RP. For all interaction models, we controlled for: age, site, treatment hours completed, prior treatment episodes, and baseline substance dependence severity. For interaction models with the treatment × race interaction term, we also controlled for group race/ethnicity composition. For interaction models with the treatment × group race/ethnicity composition interaction term, we also controlled for individual race/ethnicity.