Comparison 2. NBAS or NBO versus control: subgroup analysis.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Quality of caregiver‐infant interaction	7	304	Std. Mean Difference (IV, Random, 95% CI)	‐0.53 [‐0.90, ‐0.17]
1.1 NBAS	5	231	Std. Mean Difference (IV, Random, 95% CI)	‐0.49 [‐0.99, ‐0.00]
1.2 NBO	2	73	Std. Mean Difference (IV, Random, 95% CI)	‐0.69 [‐1.18, ‐0.20]