Table 3. Homework Use as a Predictor of PTSD Levels and Subsequent Changes in PTSD.

	Homework by Time Interactions (Combined Sample)					Written Account by Homework Interaction (Moderator Analysis)
Relationship	n	b	CR	p	d	b	CR	p	d
bHW1→S2	139	1.38	1.51	.132	0.26	0.36	0.20	.842	0.03
HW1→ΔS2-PST		0.03	0.31	.758	0.05	-0.27	-1.33	.183	-0.23
HW2→S4	136	2.65	2.83	.005	0.48	-2.48	-1.15	.251	-0.20
HW2→ΔS4-PST		-0.34	-2.82	.005	-0.48	-0.18	-0.65	.517	-0.11
HW3→S6	128	1.95	1.83	.068	0.32	-3.99	-1.63	.104	-0.29
HW3→ΔS6-PST		-0.27	-1.79	.074	-0.32	0.49	1.56	.120	0.27
HW4→S8	119	1.26	0.68	.496	0.12	-5.31	-1.37	.170	-0.25
HW4→ΔS8-PST		0.07	0.23	.820	0.04	-0.43	-0.74	.457	-0.14
HW5→S10	119	1.26	1.32	.187	0.24	-0.17	-0.07	.946	-0.01
HW5→ΔS10-PST		-0.66	-2.49	.013	-0.46	0.18	0.29	.774	0.05
HW6→S12	89	-0.59	-0.33	.739	-0.07	-3.76	-1.01	.313	-0.21
HW6→ΔS12-PST		-0.37	-0.37	.712	-0.08	-0.59	-0.26	.795	-0.06

Note. Results on the left side indicate findings for the entire sample, homework by time interaction. Analyses represented on the right side included an interaction between time and a variable indicating whether or not the trauma account was assigned. HW = homework completion, S = session, n = sample size for that analysis, CR = critical ratio (b/standard error of b, which follows a z-distribution), p = p -value, d = effect size estimate calculated using $d=\frac{2\mathit{\text{CR}}}{\sqrt{n}}$, with .20, .50, and .80 indicating the cutoffs for small, medium, and large effect sizes. The Level-1 regression equation for the analysis was Y_ij = b_o + b₁Time1 + b₂Time2 + r_ij, where Y_ij = PTSD symptoms for participant at assessment i for participant j, b_o = the regression intercept (PTSD levels at that session); b₁Time1 = Change in PTSD from that session to the posttreatment assessment; PTSD Time2 = the difference in rate of change in PTSD before and after the session, and r_ij = the level-1 residual. All of these terms as well as homework use × time parameters interactions were included in the model. However, to facilitate interpretation of the results, only the parameters representing the impact of HW on PTSD levels and subsequent change are presented on the left, and the main effects of Time, HW, and the moderator, as well as all two way and three way interactions were included in the model reported on the right. Coefficients for the entire model can be obtained from the authors.