Normative Data of the Self-Report Version of the German Strengths and Difficulties Questionnaire in an Epidemiological Setting

OBJECTIVE: This study served to establish German norms for the Strengths and Difficulties Questionnaire self-report (SDQ-S) by using data from a representative epidemiological sample from the German National Health Interview and Examination Survey for Children and Adolescents (KiGGS study). Although the German version of the SDQ has been widely used and normative data for the parent version (SDQ-P) exist, no German norms for the self-report version have been reported, so that practitioners had to rely on the available British norms. In addition, we investigated whether sex- and age-specific norms are necessary.

METHODS: At the baseline of the KiGGS study, SDQ-S ratings were collected from n = 6,726 children and adolescents between 11 and 17 years (n = 3,440 boys und n = 3,286 girls). We assessed the internal consistency and age/sex effects of the SDQ-S. Confirmatory factor analysis was conducted to assess the factor structure of the SDQ-S. Banding scores were developed to differentiate children and adolescents with levels of difficulties and categorized them as "normal," "borderline," and "abnormal." General as well as age- and sex-specific bandings were created for both total score and subscales of SDQ-S. In addition, the German norms of the SDQ-S were compared with those of the UK, Norway, and Thailand.

RESULTS: The five-factor solution of the SDQ-S (including Emotional symptoms, Conduct problems, Hyperactivity/Inattention, Peer problems, and Prosocial behavior) provided a satisfactory fit to the data. Moderate internal consistencies (Cronbach's α) were observed for the scales Emotional symptoms, Hyperactivity/Inattention, and Total difficulties score, whereas insufficient internal consistency was found for the scales Peer problems and Conduct problems. However, using McDonald's ω as a more appropriate measure of homogeneity, internal consistencies were found to be satisfactory for all subscales and for Total difficulties. Normative banding scores were established conservatively to avoid producing too many false positives in the category "abnormal." In line with previous research, girls showed more emotional problems but fewer Peer problems than boys. German normative bandings of SDQ-S were similar to the original British bandings and those of other countries.

CONCLUSIONS: This study of the German SDQ-S in a large representative epidemiological sample presents evidence of partly moderate to good psychometric properties. It also supports the usefulness of SDQ-S as an effective and efficient instrument for child and adolescent mental health problems in Germany. German normative banding scores of SDQ-S established in this study were comparable with the original British norms as well as with those of other countries, so that SDQ-S can be recommended as a psychopathological broadband-screening tool.