Impact of Grouping Behavior Among School-Aged Children on Evacuation Efficiency Under Ordered and Disordered Evacuation Forms

School-aged children are a vulnerable group in emergencies, showing distinct grouping behaviors under ordered and disordered evacuations. This study investigated how these behaviors affect evacuation efficiency and how spatial conditions shape outcomes. Two drills were conducted on 216 children aged 6–12. Indicators including movement speed, crowd density, and grouping type were analyzed from video data. Disordered evacuation featured unstable group structures, variable speeds, and faster but less consistent movement. In contrast, ordered evacuation improved group stability and coordination, with only slight speed reductions (16% in corridors and 12% in stairways). Spatial conditions also affected grouping behavior. Wider corridors encouraged lateral dispersion and required stronger guidance, whereas stairways benefited from reduced control to alleviate congestion. These findings highlight how grouping behavior affects evacuation efficiency across evacuation forms and spatial settings, and underscore the importance of coordinating evacuation management strategies with building circulation design. The results provide empirical evidence for enhancing the safety of school-aged children during evacuations and offer practical guidance for optimizing school evacuation strategies and educational building design.