Table 2.

Generalized estimating equations predicting substance use days from pretreatment to 12 months post-treatment: Tests of model effects

Source	Wald Chi-Square	df	p
(Intercept)	244.06	1	<.001
Condition	0.39	2	.82
Timepoint	86.35	5	<.001
Days in IOP	0.29	1	.59
Days in restricted environment	37.02	1	<.001
Condition*Timepoint	20.71	10	.02

Note. IOP = Intensive Outpatient Treatment; Days in IOP = days in TAU prior to pretreatment assessment.