Evolving Trajectories of Educational Expectations and Science Performance during Middle School and STEM Degree Attainment of Youth in Adulthood

Extensive research has established the positive relationship between youths’ educational expectations and academic performance. However, limited attention has been paid to how the developmental and growth trajectories of educational expectations may dynamically shape the development and growth in science performance during middle school—a critical period for fostering long-term STEM achievement. Leveraging longitudinal panel data from the second-cohort sample of the Longitudinal Study of American Youth (LSAY), this study employs parallel-process latent growth curve modeling (PP-LGCM) to investigate how evolving educational expectations and science performance of youths during early adolescence jointly predict STEM degree attainment in adulthood. Results reveal that the development and growth in educational expectations of youths across middle school years positively drive their corresponding development and growth in science performance. These parallel trajectories collectively and significantly predict youths’ successful graduation with a four-year STEM degree in adulthood, with the developmental and growth trajectories of science performance significantly mediating the relationship. Monte Carlo simulations confirmed the robustness of these findings, demonstrating strong statistical power (>0.80) and minimal bias (<5%) for all focal parameters, with sensitivity analyses indicating model stability across varying sample sizes. The findings underscore the interconnected, cumulative, and progressive nature of academic motivation and science competency during early adolescence in relation to youths’ later STEM achievement, challenging static conceptualizations of these constructs. By framing educational expectations and science learning as dynamic, time-varying processes, this study advances theoretical and methodological approaches to STEM development research. Practical implications highlight the need for holistic educational policies and interventions that nurture both aspirational growth and foundational science competence during formative school years, thereby strengthening pathways to STEM success. © The Author(s) 2025.