Abstract
Emotional intelligence (EI) has increasingly been conceptualized as a developable set of emotional abilities contributing to adaptive functioning across adulthood. However, longitudinal evidence obtained in ecological organizational contexts remains limited, particularly for performance-based emotional intelligence frameworks. The present longitudinal field study investigated the effects of a large-scale emotional intelligence intervention implemented within a French public-sector institution using the QEPro performance-based framework of ability emotional intelligence. The intervention combined experiential learning, emotional decoding, and emotion regulation training over approximately 18 months. N = 90 participants completed both pre-and post-training assessments. Linear mixed-effects models revealed significant improvements in global emotional intelligence scores as well as across most emotional competencies. The intervention was additionally associated with a medium-to-large effect size for the global QEPro score (Cohen's dav = 0.73). The strongest gains were observed for Interpreting Emotional Cues, Emotion Regulation, and Identifying Emotions. Reliable Change Index analyses indicated that 42.2% of participants demonstrated emotional progression exceeding expected measurement variability. Findings are consistent with the hypothesis that ability emotional intelligence remains developmentally plastic during adulthood and may significantly evolve through structured experiential learning processes.