Understanding students’ intentions to study science at upper-secondary school continues to be a central concern for science education. Prior research has associated students’ confidence with their intentions to study science, although under-confidence and over-confidence (lower or higher confidence than expected given someone’s attainment) has not been considered in detail. Under-confident students may not select subjects that they might otherwise succeed in and enjoy, which may be a fundamental barrier. Accordingly, this study explored whether under-confident, accurately-evaluating, and over-confident students expressed different attitudes towards their science education, and explored how under-confidence and over-confidence might influence students’ science intentions. Existing nationally-representative data and newly-collected data from secondary school students in England were considered in order to provide complementary insights and to enhance the plausibility of the findings. Multiple analytical approaches were applied to consider under-confidence and over-confidence, including calculating various indicators of accuracy/bias and applying various approaches to grouping students. The results highlighted that under-confidence and over-confidence may be problematic, not simply through associating with lower or higher attitudes, but also through students considering their choices in different ways
