Table 2.

Multilevel results on ADHD symptoms and peer acceptance.

	ADHD symptoms (observation)			Hyperactivity (actigraph)a			Peer acceptance
	Coefficient	SE	p-value	Coefficient	SE	p-value	Coefficient	SE	p-value
Fixed effects
Constant	14.649	3.833	<0.001	326.929	55.046	<0.001	0.465	0.120	<0.001
Baseline level of DV	0.278	0.069	<0.001	0.527	0.060	<0.001	0.830	0.033	<0.001
Gender (Boys = 0)	-4.435	4.555	0.215	-21.745	33.342	0.515	-0.024	0.059	0.687
Group (Time = 0)b	1.635	4.837	0.736	16.919	46.423	0.716	0.139	0.077	0.071
Time	-0.140	0.236	0.555	0.699	2.318	0.763	0.012	0.004	0.008
Group∗Time	0.133	0.337	0.639	0.565	3.285	0.864	-0.002	0.006	0.760
Random effectsc
${\mathrm{\sigma }}_{\mathrm{u}\mathrm{0}}^{\mathrm{2}}$ (classroom)	40.675	33.813		-	-		0.052	0.011
${\mathrm{\sigma }}_{\mathrm{u}\mathrm{0}}^{\mathrm{2}}$ (student)	30.645	37.966		4938.676	2558.918		0.086	0.014
σu01 (student)	-	-		-	-		-0.008	0.001
${\mathrm{\sigma }}_{\mathrm{u}\mathrm{1}}^{\mathrm{2}}$ (student)	-	-		-	-		0.0001	0.0001
${\mathrm{\sigma }}_{\mathrm{e}}^{\mathrm{2}}$	211.746	29.281		17830.428	2724.235		0.051	0.007

ADHD, Attention-Deficit Hyperactivity Disorder; DV, Dependent Variable. ${\mathit{\sigma }}_{\mathit{u}\mathit{0}}^{\mathit{2}}$ = Random intercept; σ_u01 = Covariance between random intercept and random slope; ${\mathit{\sigma }}_{\mathit{u}\mathit{1}}^{\mathit{2}}$ = Random slope.^aAverage hyperactivity at school in Activity Counts per minute.^bThe fixed group effect represents group differences at baseline. The control group was used as reference group.^cOnly the random intercepts and random time slopes that were part of any of the final models are depicted in this Table.