Table 6.

Cutoff values per year of age for the SDQ parent-report version for females, males, and without distinguishing between genders

Age	SDQ scale
	Emotional		Conduct		Hyperactivity		Social		Prosocial		Externalizing		Internalizing		Total
	‘Bord.’	‘Abn.’	‘Bord.’	‘Abn.’	‘Bord.’	‘Abn.’	‘Bord.’	‘Abn.’	‘Bord.’	‘Abn.’	‘Bord.’	‘Abn.’	‘Bord.’	‘Abn.’	‘Bord.’	‘Abn.’
Female
12	4	5	2	3	5	6	2	4	6	5	6	8	6	8	11	15
13	4	5	2	3	4	6	3	4	6	5	6	8	6	8	11	15
14	4	5	2	3	4	6	3	4	6	5	5	7	6	8	11	14
15	4	5	2	3	4	5	3	4	6	5	5	7	6	8	10	14
16	4	5	2	3	3	5	3	4	6	5	5	7	6	8	10	14
17	4	5	2	3	3	5	3	4	6	5	5	7	6	8	10	13
Males
12	4	5	2	3	6	8	3	5	6	5	8	10	6	9	13	18
13	4	5	2	3	6	7	3	5	6	5	8	10	6	9	13	18
14	4	5	2	3	6	7	3	5	6	5	7	9	6	9	13	17
15	3	5	2	3	5	7	3	4	6	5	7	9	6	9	13	17
16	3	5	2	3	5	6	3	4	5	4	7	9	6	8	12	17
17	3	5	2	3	5	6	3	4	5	4	6	8	6	8	12	16
Total
12	4	5	2	3	6	7	3	4	6	5	6	10	6	9	13	17
13	4	5	2	3	5	7	3	4	6	5	6	9	6	8	12	17
14	4	5	2	3	5	6	3	4	6	5	6	9	6	8	12	16
15	4	5	2	3	5	6	3	4	6	5	6	8	6	8	11	16
16	3	5	2	3	4	6	3	4	6	5	6	8	6	8	11	15
17	3	5	2	3	4	5	3	4	6	5	5	7	6	8	11	14

SDQ Strengths and Difficulties Questionnaire, ‘Bord.’ ‘borderline’, ‘Abn.’ ‘abnormal’

For all SDQ scales except the prosocial scale, scale scores equal to or higher than the displayed cutoff value (≥ 90th percentile) are considered ‘abnormal’. For the prosocial scale, scale scores equal to or lower than the displayed cutoff value (≤ 10th percentile) are considered ‘abnormal’

For all SDQ scales except the prosocial scale, scale scores equal to the displayed cutoff value up to the cutoff value for ‘abnormal’ (80th up to the 90th percentile) are considered ‘abnormal’. For the prosocial scale, scale scores scale scores equal to or lower than the displayed cutoff value (20th down to the 10th percentile) are considered ‘borderline’

The complete norms for all ages and scales of the parent-reported SDQ version are presented in Tables S4–S6 (Additional file 2)