Table 3.

Mixed‐effect model parameters for OCDI comprehension score

	Unconditional means model				Unconditional growth model				Final model
	Parameter	SE	Z	p	Parameter	SE	Z	p	Parameter	SE	Z	p
Fixed effects
Initial status
Intercept	−0.14	0.24	−0.60	.55	−2.49	0.1	−23.97	<.001	−2.5	0.11	−23.6	<.001
Sleep time									−0.1	0.07	−1.36	<.001
Sleep efficiency									−0.01	0.05	−0.2	.843
Breastfeeding (ref: formula fed)									0.08	0.06	1.19	.23
Rate of change
Age					0.34	0.01	33.8	<.001	0.31	0.01	25.35	<.001
Number of naps									0.03	0.01	3.21	.001
Sleep efficiency									0.03	0.01	2.76	.006
Sex (ref: male)									0.05	0.01	3.78	<.001

	Variance	SD	Variance	SD	Variance	SD
Random effects
Intercept	9.01	3	2.14	1.46	2.05	1.43
Age	0.15	0.39	0.02	0.14	0.02	0.13

OCDI, Oxford Communicative Development Inventory; SE, standard error; SD, standard deviation.