Table 3.

Parameter Estimates and Standard Errors

					95% confidence intervalb
Effect	Estimate	Standard error	t	Probabilitya	Lower	Upper
Mediation model
cc,d	-0.31	0.11	-2.70	.004
ae	0.29	0.17	1.72	.04
b	0.06	0.04	1.63	ns
ab	0.02	0.02			-0.004	0.049
Moderated mediation model
Pretreatment motivation level: 0
c	-0.30	0.18	-1.71	.05
a	-0.06	0.26	-0.22	ns
b	0.18	0.05	3.73	nsf
ab	-0.01	0.05			-0.105	0.081
Pretreatment motivation level: 1
c	-0.30	0.13	-2.36	.01
a	0.14	0.19	0.73	ns
b	0.10	0.04	2.77	nsf
ab	0.01	0.02			-0.022	0.057
Pretreatment motivation level: 2
c	-0.30	0.12	-2.60	.005
a	0.33	0.17	1.95	.03
b	0.02	0.04	0.70	ns
ab	0.01	0.01			-0.014	0.037
Pretreatment motivation level: 3
c	-0.30	0.15	-2.02	.02
a	0.52	0.22	2.39	.01
b	-0.05	0.05	-1.15	ns
ab	-0.02	0.03			-0.088	0.016
Pretreatment motivation level: 4
c	-0.30	0.21	-1.45	ns
a	0.71	0.30	2.35	.01
b	-0.13	0.06	-2.12	.01
ab	-0.09	0.06			-0.228	-0.003

Note. In contrast to Table 2, an observation was excluded from the results reported here if it was missing on any of the key variables in the study.

^aDirectional (one tailed).

^bAsymmetric 95% confidence intervals for ab product from Prodclin2 program (MacKinnon, Fritz, Williams, & Lockwood, 2007).

^cFor parsimony, only treatment contrasts between the standard care (SC) condition and the BI (SC plus brief motivational intervention) and BIB (BI plus a booster session) condition are presented here. Contrasts between the BIB and SC conditions were found to be directionally consistent but weaker.

^dAll analyses involving negative consequences covary out the effect of pretreatment negative consequences.

^eAll analyses involving motivation covary out the effect of pretreatment motivation.

^fOn the basis of theory, the relationship between change in motivation and change in negative consequences was tested directionally. If tested nondirectionally, this relationship would have achieved statistical significance for motivation levels 0 and 1, albeit in a direction contrary to the postulated theory.