Table 2.

Internal consistency (Cronbach’s alphas) of scores on the SDQ Total Difficulties scale and subscales, and test characteristics of the SDQ Total Difficulties using the CBCL Total Problems score as criterion

	3-4 years	4-7 years	7-11 years	12-14 years
SDQ norms
Clinical SDQ score
Cut-off point	> 10	> 14	> 13	> 11
% children with elevated SDQ TDS score	10.0	9.2	9.0	10.6
Borderline SDQ score
Cut-off point	> 7	> 10	> 10	> 8
% children with elevated SDQ score	20.6	21.1	17.7	21.3
Cronbach’s alpha
SDQ scales
Total difficulties	0.78	0.79	0.80	0.77
Emotional symptoms	0.52	0.74	0.71	0.69
Conduct problems	0.63	0.54	0.56	0.39
Hyperactivity	0.75	0.77	0.78	0.76
Peer problems	0.52	0.49	0.55	0.63
Prosocial	0.65	0.83	0.67	0.75
Validity indices
Clinical SDQ score
Sensitivity	0.70	0.71	0.75	0.58
Specificity	0.94	0.95	0.96	0.95
Borderline SDQ score
Sensitivity	0.84	0.90	0.92	0.81
Specificity	0.80	0.83	0.88	0.86
AUC (95% confidence interval)	0.92 (0.88-0.95)	0.94 (0.93-0.96)	0.96 (0.95-0.98)	0.93 (0.91-0.95)

TDS Total difficult scale, AUC Area under the curve