. Author manuscript; available in PMC: 2016 Oct 12.

Published in final edited form as: J Soc Social Work Res. 2015 Oct 12;6(4):591–616. doi: 10.1086/684123

Table 2. Mixed Model Analyses of Variance (ANOVAs) Comparing Mean Parenting Stress Index Scores.

	Waitlist Control (G0)	Brief PCIT (G1)	Extended PCIT (G2)
Outcomes	M (SE)	M (SE)	M (SE)
Total Stress Scale				Between-Group Effects
					(G0 vs. G1 + G2)^b		(G1 vs. G2)^c
Time 1	85.20	90.16	89.77	Omnibus Test^a	Linear	Quadratic	Linear	Quadratic

	(2.84)	(2.79)	(3.31)	p = .007	p = .027	p = .029	p = .727	p = .081
Time 2	86.56	79.15	83.31	ES = .49	ES = .45	ES = .45	ES = .07	ES = .30
	(3.03)	(2.99)	(3.55)	Within-Group Effects ^d
Time 3	80.57	77.41	75.35	(G0)		(G1)		(G2)
	(3.19)	(3.10)	(3.61)	p = .086	p < .001			p < .001

Parental Distress				Between-Group Effects ^d
					(G0 vs. G1 + G2)^b		(G1 vs. G2)^c
Time 1	23.47	25.02	23.51	Omnibus Test^a	Linear	Quadratic	Linear	Quadratic

	(1.095)	(1.07)	(1.27)	p = .868	p = .990	p = .305	p = .926	p = .743
Time 2	23.19	23.56	22.37	ES = .14	ES = .02	ES = .20	ES = .02	ES = .07
	(1.16)	(1.14)	(1.36)	Within-Group Effects ^d
Time 3	21.95	23.55	21.91	(G0)		(G1)		(G2)
	(1.19)	(1.15)	(1.35)	p = .252	p = .172			p = .302

Parent-Child Dysfunctional Interaction				Between-Group Effects
					(G0 vs. G1 + G2)^b		(G1 vs. G2)^c
Time 1	26.84	27.68	28.11	Omnibus Test^a	Linear	Quadratic	Linear	Quadratic

	(1.03)	(1.01)	(1.19)	p = .006	p = .013	p = .018	p = .446	p = .237
Time 2	26.53	22.48	23.85	ES = .60	ES = .50	ES = .47	ES = .16	ES = .24
	(1.11)	(1.10)	(1.30)	Within-Group Effects ^d
Time 3	23.89	21.81	20.94	(G0)		(G1)		(G2)
	(1.16)	(1.12)	(1.30)	p = .02	p < .001			p < .001

Difficult Child				Between-Group Effects
					(G0 vs. G1 + G2)^b		(G1 vs. G2)^c
Time 1	34.89	37.46	38.14	Omnibus Test ^a	Linear	Quadratic	Linear	Quadratic

	(1.35)	(1.32)	(1.57)	p = .002	p = .004	p = .164	p = .90	p = .02
Time 2	36.91	33.13	37.37	ES = .55	ES = .60	ES = .14	ES = .03	ES = .49
	(1.45)	(1.43)	(1.69)	Within-Group Effects ^d
Time 3	35.03	32.15	32.54	(G0)		(G1)		(G2)
	(1.52)	(1.48)	(1.72)	p = .157	p < .001			p = .002

Note. Coefficients are least squares means. M = mean; SE = standard error; ES = effect size reported as Cohen’s d.

Omnibus interaction tests of study condition by time.

Interaction contrasts comparing trends of waitlist control (G0) to the average of treatment conditions (G1 + G2).

Interaction contrasts comparing trends of the two treatment conditions (G1 vs. G2).

Within-group comparison of time effects for each treatment condition.