Table 6.

Mediation Analyses to test the Proposed Causal Mechanism

		Unknown Difference Set				Unknown Compared Set				Unknown Referent Set
Model		B	SE	p	PC	B	SE	p	PC	B	SE	p	PC
Step 1	Treatment on Outcome (Difference Problem Subtest)
	Constant	1.99	0.26	< 0.001		5.00	0.33	< 0.001		4.31	0.25	< 0.001
	Difference Problem covariate	0.54	0.05	< 0.001		0.51	0.04	< 0.001		0.52	0.05	< 0.001
	Treatment	−0.89	0.21	< 0.001	c	−1.06	0.38	0.008	c	−1.47	0.32	< 0.001	c
Step 2	Treatment on Mediator (Relational Tasks)
	Constant	19.39	0.78	< 0.001		19.39	0.78	< 0.001		19.39	0.78	< 0.001
	Treatment	−2.09	0.97	0.041	a	−2.09	0.97	0.041	a	−2.09	0.97	0.041	a
Step 3	Treatment and Mediator (Relational Tasks) on Outcome (Difference Problem Subtest)
	Constant	1.01	0.25	< 0.001		0.99	1.19	0.41		1.65	0.68	0.023
	Difference Problem covariate	0.39	0.04	< 0.001		0.33	0.05	< 0.001		0.39	0.05	< 0.001
	Relational Tasks posttest	0.073	0.01	< 0.001	b	0.113	0.06	< 0.001	b	0.095	0.018	< 0.001	b
	Treatment	−0.85	0.19	< 0.001	c'	−0.62	0.33	0.073	c'	−1.3	0.29	< 0.001	c'

Note. PC = the path coefficient relevant to the mediation analysis in Figure 1. To assess the significance of the indirect effect for unknown difference and referent sets, we looked at paths a*b to assess the interaction.