Internal structure validity of the Self Description Questionnaire II and latent academic self-concept profiles of 9th grade students

The study was designed in two parts. First, we assessed the internal structure validity, measurement invariance across gender, and reliability of scores on the Slovenian version of the Self Description Questionnaire II (SDQ-II) in a sample of 9th grade students from Slovenian primary schools ( N = 370). The modified nested Marsh/Shavelson model fit the data best, while measurement invariance across gender was not supported. In the second part, we used latent profile analysis to investigate different profiles of students' academic self-concept. We identified five distinct and interpretable profiles that differed by profile level (high, medium, and low academic self-concept) and profile shape (high academic self-concept in one domain vs. low academic self-concept in another). Subsequent covariate analysis revealed meaningful differences between latent profiles by gender and in overall and three subject-specific school grades (math, Slovenian, geography). The psychometric properties of the SDQ-II and individual differences in academic self-concept are discussed. This study has important educational implications for researchers, teachers and school counsellors. The Slovenian version of the SDQ-II questionnaire was validated, providing a reliable tool for understanding the adolescents' academic self-concept (ASC). The identification of ASC profiles supports personalized teaching strategies and emphasizes the link between ASC and academic achievement, highlighting the importance of fostering students' self-concept. It also expands the understanding of ASC profiles in students by uncovering qualitative, i.e. different patterns of profiles for domain-specific self-concepts, and quantitative differences, i.e. different profile levels from low to high self-concepts. • Modified nested Marsh/Shavelson model of academic self-concept provided a good fit. • Five academic self-concept profiles were identified with the latent profile analysis. • Profiles differed quantitatively (in levels) and qualitatively (in shape). • Males and females were relatively equally represented in four out of five profiles. • Profiles with higher academic self-concept had higher grades in the corresponding domains.