Amplifiers or Equalizers? A Longitudinal Study of LLM Evolution in Software Engineering Project-Based Learning

Abstract: As LLMs reshape software development, integrating LLM-augmented practices into SE education has become imperative. While existing studies explore LLMs' educational use in introductory programming or isolated SE tasks, their impact in more open-ended Project-Based Learning (PBL) remains unexplored. This paper introduces a two-year longitudinal study comparing a 2024 (using early free LLMs, $n$=48) and 2025 (using the latest paid LLMs, $n$=46) cohort. Our findings suggest the latest powerful LLMs' dual role: they act as "equalizers," boosting average performance even for programming-weak students, providing opportunities for more authentic SE practices; yet also as "amplifiers," dramatically widening absolute performance gaps, creating new pedagogical challenges for addressing educational inequities.