LAUSR

The Strengths and Difficulties Questionnaire self-report (SDQ-SR) is a widely used instrument to identify emotional and behavioral problems by Preventive Child Healthcare (PCH). It is a valid instrument in more highly educated adolescents, however evidence regarding lower educated adolescents (vocational school) is lacking. The aim of this study was to compare the psychometric properties of the SDQ-SR when used with less well and more highly educated ('higher') adolescents, and to explore opinions of adolescents and PCH professionals regarding its suitability. We included 426 adolescents (130 lower and 296 higher educated), who completed the SDQ-SR. We compared how the psychometric properties (i.e. internal consistency) applied to lower and higher educated adolescents. We assessed whether the five-factor structure of the SDQ is invariant across different educational levels. Moreover, we interviewed 24 adolescents from pre-vocational secondary education schools, and performed online focus group interviews with 17 PCH professionals. The internal consistencies (Cronbach's alphas) per SDQ scale were comparable for lower and higher educated adolescents. On most subscales the lower educated adolescents had higher mean scores than the higher educated adolescents. Findings on differences by educational level for the other psychometric properties, i.e. multi-group invariance and single group (CFA) analyses, were inconsistent, with some measures showing unequal factor loadings but others not. Although professionals and lower educated adolescents reported that the SDQ includes many outdated and difficult words, professionals nevertheless perceived the SDQ-SR as a valid instrument. The psychometric properties of the SDQ-SR are sufficient for use among lower educated adolescents. However, for optimal implementation in PCH there is a need for improvement in the wording of the SDQ, as expressed by both professionals and adolescents. The psychometric properties of the SDQ are sufficient for use among lower educated adolescents. For optimal implementation the SDQ needs to be updated in more understandable language.