A systematic review and meta-analysis on the effect social groups have on the egress times of pedestrian crowds

Conflicting results in the literature raise the question of how reliable findings from single experiments on pedestrian crowd movements are. An important example is the effect social groups have on crowd egress times from confined spaces where both increases and decreases were reported. We identify only six comparable studies and conduct the first analysis on this topic that integrates evidence from multiple studies quantitatively, accounting for different sample sizes. The aggregated findings suggest social groups increase average egress times but there is insufficient evidence to reject the null hypothesis of no effect. The conflicting results across published studies are thus likely to have arisen by chance, as experiments are statistically underpowered for determining a small effect. We find no evidence for publication bias in terms of findings or statistical power. Our work presents a quantitative basis for discussing the statistical reliability of experiments considering the high context-dependency of pedestrian dynamics.

学界现有文献中的研究结论存在冲突，这引发了一个关键问题：针对行人群体运动的单实验研究结论，其可靠性究竟如何。其中一个典型案例便是社会群体对封闭空间内人群疏散时间的影响——已有研究分别报道了该影响会延长或缩短疏散时间的两种截然相反的结果。我们仅检索到6项具备可比性的相关研究，并针对该主题开展了首次定量整合多项研究证据的分析，同时纳入了不同样本量的影响因素。聚合分析结果显示，社会群体确实会延长人群的平均疏散时间，但目前尚无足够证据推翻"无影响"的原假设。由此可见，已发表研究间的结论冲突大概率源于随机误差：现有实验的统计效力不足以检测出该类微小效应。我们未发现研究结论或统计效力方面存在发表偏倚的证据。本研究为探讨行人动力学极强的情境依赖性下的实验统计可靠性，提供了定量分析基础。