Is shooting efficiency stable over time? A five-season longitudinal analysis from EuroLeague basketball

Longitudinal evidence on the stability of individual shooting efficiency in elite European basketball remains limited. This study examined within-season variability, between-season profile persistence, and longitudinal progression in shooting efficiency in EuroLeague players across five consecutive seasons (2019–2020 to 2023–2024), considering two-point field-goal percentage (2P%), three-point field-goal percentage (3P%), and free-throw percentage (FT%) at the player-season level. Official EuroLeague box-score data were analysed retrospectively, yielding 1,097 player-season observations from 345 players. Eligible player-seasons were classified using seasonal mean percentage and log-transformed attempt-weighted CV. Variable-specific constrained Gaussian mixture models identified seasonal shooting profiles, with player-seasons classified according to posterior probabilities. Season-to-season transitions were summarised using transition matrices, observed agreement, and kappa. FT% showed the highest between-season agreement (observed agreement = 70.8–82.7%; kappa = 0.417–0.631), whereas 3P% showed the lowest profile persistence (observed agreement = 36.2–50.0%; kappa = −0.081 to 0.111). Mixed-effects models indicated a significant positive linear trend for mean 3P% and a significant season effect for mean FT%, but no systematic reduction in attempt-weighted CV. These findings suggest that elite competitive exposure was associated with changes in mean shooting efficiency, but not with a consistent improvement in within-season shooting variability. Practitioners should monitor both efficiency and variability, particularly when evaluating and training three-point shooting.