# Understanding Safety Performance of Prefabricated Construction Based on Complex Network Theory
## 1 Introduction  
As one of the worst global pandemics in human history, the coronavirus disease 2019 (COVID-19) has infected at least 465 million people and caused more than 6.06 million deaths, which continues to exact a heavy toll across the world and ravages the world economy in the context of new virus variants. With the elevated COVID-19 caseloads overwhelming the admission capacity of designated infectious diseases hospitals, the construction of emergency hospitals is supposed to be a practical and essential move to control the pandemic, which was verified in Wuhan, the epicenter of the COVID-19 outbreak and main battlefield in China. The two specialty field hospitals of Huoshenshan and Leishen-shan were built from the ground up within 9 and 12 days, respectively [1]. Such remarkable construction speed of the two hospitals was profited by employing prefabrication technology which avoids time-consuming in situ construction work. The United States and other western countries also adopted this technology to quickly install ICUs and build various temporary building shells as isolation spaces for epidemic prevention and control, injecting flexibility into the traditional medical environment [2]. Prefabrication is an industrialized built process that involves a certain amount of building components manufactured in specialized facilities, transported to construction sites, and assembled at designated locations [3]. More than shortening construction duration [4], prefabricated construction is highly praised and increasingly advocated for its inherent benefits of reducing lifecycle cost [5], increasing production efficiency [6], and enhancing environmental performance [7]. Under the promotion of national policies, the scale of China's prefabricated construction market has gradually expanded, and a total of630 million square meters of prefabricated buildings were built in 2020 in China, accounting for 20.5% of the newly constructed building area. However, along with the increasing proportion of prefabricated buildings in China, the improvement in safety performance is limited. There is an unapparent indication supporting a decline in accident incidence rate, which is illustrated in Figure 1. Meanwhile, similar evidence could also be found in the USA, where the Bureau of Labor Statistics reported that workers in prefabricated building projects are exposed to higher rates of injuries and accidents (10.2 per 100 workers) than the rates (5.2 per 100 workers) in the traditional cast-in-place construction projects [8]. Not only are these results contrary to the conception that prefabricated construction is comparatively safe to some extent, but they also raise doubts about the general perception of safety concerning prefabricated building projects. Compared with the conventional construction method, prefabricated building projects would be up against manifold safety risks and considerable uncertainties on account of their unique and innovative processes [9]. Not only this, the safety risks in prefabricated building projects are superficially fragmented, but substantially interdependent [10]. One safety risk could be the incentive for another safety risk, resulting in several safety risks concurrently emerging in one accident [11]. These interactions among safety risks form the prefabricated construction safety risk network (PCSRN) which impedes conspicuous improvement in the safety performance of prefabricated building projects. In the content of the accelerative promoting prefabricated construction [3], capturing the intrinsic characteristics of PCSRN and understanding the interdependencies among the safety risks are of paramount importance. Against these backgrounds, this paper accomplishes a comprehensive analysis in order to acquire adverse risks compromising the safety of prefabricated constructions and investigate underlying interactions among them for suggesting preventive strategies to improve their safety performance.