Samenvatting

Supporting students' self-regulated learning (SRL) is essential in education, yet most interventions adopt a one-size-fits-all approach, overlooking individual differences in students' ability to engage in SRL. Tailored instruction requires reliable assessment tools that distinguish between students' availability (knowledge) and production (actual use) of SRL strategies—an important conceptual distinction that has not yet been operationalized. This study developed and validated the SRL-IBSL, a 17-item questionnaire assessing the availability and production of SRL strategies in the context of inquiry-based science learning among primary students. The instrument covers four key SRL strategies: Time and Effort Planning, Activation of Prior Knowledge, Monitoring of Behavior, and Monitoring of Learning. Validation results support the questionnaire's internal structure and reliability, with partial evidence for its convergent and discriminant validity. Moderate correlations with teacher appraisals and small group differences based on science competency levels suggest the questionnaire's potential for group-level assessment and instructional use. The SRL-IBSL provides a practical tool for researchers and educators to identify students' SRL profiles and adapt instruction accordingly, offering a promising step toward more personalized support for SRL in primary science education.