TABLE 2.

Scale characteristics, Cronbach’s alpha (α) and range of item-total correlations of the ILF-EXTERNAL.

		Total sample (N = 474)				Screening negatives (n = 32)
Scale	k (items)	α	Item-total r (range)	Mean (SD)	N	Mean (SD)	n
ADHD symptoms	18	0.84	0.21−0.62	1.80 (0.50)	474	1.09 (0.51)	32
– Inattention	9	0.71	0.29−0.49	1.95 (0.48)	474	1.35 (0.49)	32
– Hyperactivity-Impulsivity	9	0.87	0.50−0.68	1.64 (0.73)	474	0.84 (0.62)	32
ADHD functional impairment	5	0.62	0.24−0.48	1.61 (0.59)	472	1.03 (0.49)	31
ODD/CD symptoms−short version	13	0.84	0.25−0.62	0.85 (0.50)	450	0.55 (0.55)	23
– ODD symptoms	8	0.82	0.41−0.61	1.12 (0.63)	451	0.78 (0.68)	24
– CD symptoms−short version	5	0.60	0.22−0.47	0.40 (0.43)	450	0.22 (0.37)	23
Disruptive mood dysregulation	5	0.83	0.53−0.67	1.08 (0.73)	452	0.73 (0.65)	24
Limited prosocial emotions	11	0.77	0.23−0.58	0.50 (0.42)	444	0.37 (0.30)	22
ODD/CD functional impairment	5	0.86	0.61−0.71	0.93 (0.78)	442	0.49 (0.73)	21

Screening negatives are participants who have been screened for eligibility of the ESCAschool study and are characterized by subclinical ADHD symptoms. ADHD, attention-deficit/hyperactivity disorder; CD, conduct disorder; k, number of items which form a particular scale; ODD, oppositional defiant disorder.