. 2021 Jun 28;51(9):1420–1430. doi: 10.1017/S003329172100163X

Table 2.

Within-effect sizes (pretest – follow-up) and subgroup analyses for PTSD severity

	k	g	95% CI	p^a	Q	p^b	I²	p^c
Condition								<0.01
Active treatment	32	1.36	1.14–1.57	<0.001	194.34	<0.001	84.05
Active control	11	0.59	0.14–1.04	<0.05	132.38	<0.001	92.45
Passive control	1	–
Treatment type^d								0.24
TFT	25	1.44	1.20–1.67	<0.001	132.08	<0.001	81.83
Non-TFT	7	1.08	0.52–1.63	<0.001	62.21	<0.001	90.36
Population								<0.01
Military	10	0.93	0.69–1.18	<0.001	32.38	<0.001	72.21
Civilian	21	1.58	1.30–1.86	<0.001	102.89	<0.001	80.56
Proportion female
<50%	12	1.04	0.79–1.30	<0.001	47.23	<0.001	76.71	<0.001
⩾50%	18	1.62	1.34–1.90	<0.001	81.64	<0.001	79.18
PTSD measure								<0.001
Interview-based	28	1.44	1.20–1.67	<0.001	158.82	<0.001	83.00
Self-rated	4	0.80	0.53–1.07	<0.001	5.16	0.16	41.91
Format								0.35
Group	4	1.00	0.18–1.82	<0.001	47.11	<0.001	93.63
Individual	28	1.41	1.18–1.63	<0.001	146.60	<0.001	81.58
Number of sessions								0.71
<10 sessions	14	1.31	1.05–1.57	<0.001	61.40	<0.001	78.82
⩾10 sessions	18	1.39	1.04–1.75	<0.001	132.88	<0.001	87.21
Type of analysis¹								0.43
Intention-to-treat	18	1.42	1.15–1.70	<0.001	112.05	<0.001	84.83
Completer	14	1.25	0.94–1.57	<0.001	59.30	<0.001	78.08
Follow-up duration								0.05
12 months	26	1.26	1.03–1.49	<0.001	157.48	<0.001	84.13
>12 months	6	1.77	1.33–2.21	<0.001	14.84	<0.05	66.32

Note. Analyses based on 21 studies (20 for proportion female).

p-values less than 0.05 represent statistical significance. 95% CI = 95% confidence intervals, g = Hedges’ g, k = number of comparisons, PTSD = posttraumatic stress disorder.

Additional subgroup analyses for PTSD indicated significantly larger treatment effects for intention-to-treat samples with higher compared to lower dropout rates (⩾20%; <20%, p < 0.01), while treatment effects remained unaffected by losses to follow-up (<40%; ⩾40%, p = 0.61). In completer samples, attrition rates had no impact on treatment outcomes (p = 0.56; p = 0.34).

p-value of Hedges’ g.

p-value of Q-statistics.

p-value between groups.

Analyses include active treatments only.