Objective: A systematic review aiming to identify and critically appraise evidence for the validity and reliability of the Strengths and Difficulties Questionnaire in pre-school children (aged 3-5).
Method:The review followed the Preferred Reporting Items for Systematic Reviews and Meta- Results: 41 studies were included (56 manuscripts). Two qualitative studies examined content and cultural validity, revealing issues with some questions. Six studies discussed language validations and recommended some changes to the wording. Evidence for discriminative validity was good (Area Under the Curve ≥ 0.80) as was evidence for convergent validity (weighted average correlation coefficients ≥0.50), except for the Pro-social scale. There was limited support for discriminant validity but good evidence for the 5-factor structural validity of the tool. One study demonstrated measurement invariance across ethnicity. Sensitivity was below 70% and specificity above 70% in most studies that examined this. One study showed that caseness indicators varied between countries. Internal consistency of the total difficulty scale was good (weighted average Cronbach's alpha parents' and teachers' version 0.79 and 0.82) but weaker for other subscales (weighted average parents' and teachers' range 0.49-0.69 and 0.69-0.83). Inter-rater reliability between parents was moderate (correlation coefficients range 0.42-0.64) and between teachers strong (range 0.59-0.81). Cross-informant consistency was weak to moderate (weighted average correlation coefficients range 0.25-0.45).Test-retest reliability was mostly inadequate. One study demonstrated moderate size effect sizes.Conclusions: Evidence for a number of psychometric properties is strong. However, the lack of evidence for test-retest reliability, cultural validity and criterion validity should be addressed given the wide-spread implementation of the tool in routine clinical practice, including in New Zealand. Furthermore, the moderate level of consistency between different informants indicate that an assessment of a pre-schooler should not rely on a single informant.