## 5 Conclusions  
In this study, small group data at a strategic level was collected and the effect of small groups on evacuation was investigated through simulation, leading to the following conclusions:  
1. Small group data at a strategic level was obtained. Small group members accounted for 60.3% of the total number of occupants, and all small groups consisted of two to four occupants. Most members were adjacent to each other, with the maximum distance between MIGs within the same small group varying from 1 m to 23 m. These data can be applied to the setup of evacuation simulation scenarios and experiments in other studies.
2. Small groups had a negative impact on overall evacuation. It increased the total evacuation time and total jam time, while decreasing the average evacuation speed of occupants.
3. The greater the distance between members, the longer the assembling time, and the greater the increase in evacuation time, total jam time, and evacuation distance. The greater the increase in total congestion time, the greater the decrease in evacuation speed.  
In terms of limitations, we set the speed of occupants in Pathfinder as the free movement speed of healthy people rather than the emergency evacuation speed of patients. Although it did not affect our research results, the speed of patients should be low in the actual evacuation process and needs further study. Meanwhile, we did not provide comparison between experimental results and the simulation process. Therefore, in future studies, we can extract the movement speeds of occupants with various walking abilities from the surveillance videos to refine the evacuation study and conduct field experiments to further validate the model. At the same time, future research can also focus on collecting small group data from other types of buildings, and further exploration is necessary to assess how the distance between members of small groups consisting of three or more occupants influences evacuation dynamics.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app14146371/s1](https://www.mdpi.com/article/10.3390/app14146371/s1)]([https://www.mdpi.com/article/10.3390/app14146371/s1](https://www.mdpi.com/article/10.3390/app14146371/s1)), Figure S1: Scatter plots; Table S1: Curve estimation.  
Conceptualization, Y.Z.; methodology, Y.Z.; software, Y.X.; validation, Y.X.; formal analysis, Y.X.; investigation, Y.X.; resources, Y.Z.; data curation, Y.X.; writing--original draft preparation, Y.X.; writing--review and editing, Y.Z.; visualization, Y.X.; supervision, Y.Z.; project administration, Y.Z.; funding acquisition, Y.Z. All authors have read and agreed to the published version of the manuscript.  
This article was funded by the General Project of National Natural Science Foundation of China, grant number 51978143.  
Not applicable.  
The data presented in this study are available from the corresponding author upon reasonable request.  
The authors are grateful for the research grants awarded by the General Project of National Natural Science Foundation of China, grant number 51978143. The authors would like to thank Beijing Huazhong RuiChi Technology Co., Ltd. for providing the Pathfinder trial version, and we also appreciate the data authorization provided by the hospital.  
The authors declare no conflicts of interest.  
Appendix AFigure 11: Density in scenarios 1.0 and 2.0 every 2 s (the first 12 s of evacuation). (**a1**) Scenario 1.0 0 s; (**a2**) Scenario 2.0 0 s; (**b1**) Scenario 1.0 2 s; (**b2**) Scenario 2.0 2 s; (**c1**) Scenario 1.0 4 s; (**c2**) Scenario 2.0 4 s; (**d1**) Scenario 1.0 6 s; (**d2**) Scenario 2.0 6 s; (**e1**) Scenario 1.0 8 s; (**e2**) Scenario 2.0 8 s; (**f1**) Scenario 1.0 10 s; (**f2**) Scenario 2.0 10 s; (**g1**) Scenario 1.0 12 s; and (**g2**) Scenario 2.0 12 s.