Table 1.

Testing Hypothesis 2: Mediation of the Effect of Treatment Condition on Long-term Tobacco Abstinence by Change in both Autonomous Self-Regulation (ASR) (Panel A) and Perceived Competence (PC) (Panel B)

Panel A:
	24mPA	7dPP
Step 1: Treatment Condition Predicting Long-term Tobacco Abstinence
Intervention	b = 1.12*	b = .54*
Step 2: Treatment Condition Predicting Change in ASR
Intervention	β = .08*	β = .08*
Step 3: Change in ASR Predicting Long-term Tobacco Abstinence while Controlling for Treatment Condition
Chang in ASR	b = .46*	b = .43***
Step 4: Treatment Condition Predicting Long-term Tobacco Abstinence while Controlling for Change in ASR
Intervention	b = 1.06*	b = .49+
z′ statistic	1.63**	2.01**

Panel B:
	24mPA	7dPP
Step 1: Treatment Condition Predicting Long-term Tobacco Abstinence
Intervention	b = 1.12*	b = .54*
Step 2: Treatment Condition Predicting Change in PC
Intervention	β = .08*	β = .08*
Step 3: Change in PC Predicting Long-term Tobacco Abstinence while Controlling for Treatment Condition
Chang in PC	b = 1.51***	b = .71***
Step 4: Treatment Condition Predicting Long-term Tobacco Abstinence while Controlling for Change in PC
Intervention	b = .92	b = .41
z′ statistic	2.47**	2.43**

Notes. ASR = Autonomous self-regulation, PC = Perceived competence, 24mPA = 24-month prolonged abstinence from tobacco, 7dPP = 7-day point prevalence tobacco abstinence. Step 1 refers to the relation of the independent variable (IV; viz., treatment condition) to the dependent variable (DV; viz., long-term tobacco abstinence). Step 2 refers to the relation of the IV to the mediating variable (MV; viz., ASR in Panel A, PC in Panel B). Step 3 refers to the relation of the MV to the DV while controlling for the IV. Step 4 refers to the relation of the IV to the DV while controlling for the MV. The z′ statistic refers to the significance of the indirect effect of the IV on the DV through the MV (24).

⁺p < .10,

^*p < .05,

^**p < .01,

^***p < .001.