Table 2. The results of Analysis I for individual and group interventions for each outcome.

		Individual			Group
	Outcome	p-value	SMD (95%CI)	I2(%)	p-value	SMD (95%CI)	I2(%)
Primary outcome	Autism general symptoms	0.28	−0.31[−0.63, 0.01]	21	N/A
Secondary outcomes	Developmental quotient	0.02*	0.36[0.05, 0.66]	20	N/A
	Developmental quotient (baseline imbalance-adjusted)	0.07	0.31[−0.02, 0.65]	26	N/A
	Expressive language	0.18	0.13[−0.06, 0.33]	0	0.92	0.11[−0.07, 0.30]	N/A
	Expressive language (baseline imbalance-adjusted)	0.18	0.13[−0.06, 0.33]	0	N/A
	Receptive language	0.19	0.17[−0.09, 0.42]	28	0.59	−0.14[−0.65, 0.37]	N/A
	Reciprocity of social interaction towards others	p<0.001***	0.59[0.25, 0.93]	18	0.04*	0.45[0.02, 0.88]	18
	Adaptive behaviour	0.60	−0.05[−0.25, 0.14]	39	0.47	0.44[−0.77, 1.65]	N/A
Other outcomes	Qualitative impairment in social interaction	0.61	−0.15[−0.40, 0.10]	0	N/A
	Qualitative impairment in communication	0.85	−0.03[−0.35, 0.29]	N/A	N/A
	Restricted repetitive and stereotyped patterns of behaviour, interests and activities	0.17	−0.21[−0.52, 0.09]	39	N/A
	Initiating joint attention	0.13	0.48[−0.14, 1.10]	78	0.57	0.15[−0.38, 0.68]	15
	Responding to joint attention	0.11	0.63[−0.14, 1.39]	97	N/A
	Imitation	0.11	0.54[−0.25, 1.33]	62	N/A
	Parental synchrony	p<0.001***	0.99[0.70, 1.29]	0	N/A
	Parenting stress	0.35	−0.30[−0.93, 0.32]	0	0.27	−0.29[−0.81, 0.22]	0

“p-value” indicates value of the test of overall synthesis. SMD indicates standard mean difference of the synthesised effect. 95% CI indicates 95% confidence interval of the SMD of the overall synthesis.

* and *** indicate statistically significant effects (p < 0.05, p < 0.01, and p < 0.001, respectively) in the analysis.

N/A indicates data synthesis could not be performed due to lack of available studies.

“baseline imbalance-adjusted” indicates results of the analysis after excluding the studies with baseline imbalances.