## 3 Results  
### Descriptive Analysis  
Data from the annual construction accident report in MOHURD [11] suggest that the number of building and civil construction accidents decreased during the period from 2010 to 2015 and increased during the period from 2015 to 2018 (see Figure 1). The fewest accidents were 442 in 2015. The corresponding worker deaths exhibited the same pattern. The State Council of the People's Republic of China categorizes four levels of accidents based on the number of fatalities per accident [26]. Accidents that result in less than three worker deaths are regarded as low. These levels rise with the increased number of fatalities to medium (3-10), high (10-30) and very high (30+). In the following sections, moderate- to high-fatality (MHF) accidents refer to accidents that result in no fewer than three worker deaths (medium, high and very high number of fatalities). Therefore, the number of worker deaths is greater than that of construction accidents annually in Figure 1 due to the occurrences of multiple fatalities associated with the MHF accidents. Change in construction industry gross domestic product (GDP) in China is a primary factor leading to patterns of construction accidents in Figure 1. China's construction industry has played an important role in the process of the country's economic growth and is a major contributor to China's GDP. According to the annual _China Statistic Yearbooks_ (for example, [22]), the construction industry increased its contribution to GDP from 3.8% in 1978 to 6.9% in 2018, and 7.2% of China's workforce were construction workers in 2018. Figure 2 displays the number of construction accidents and construction industry GDP in China during the period from 2010 to 2018. Note that the dip in the number of building and civil construction accidents in Figure 2 is due to the decrease in the growth rate of construction industry GDP during the period from 2010 to 2015 (2.29% in 2015). Therefore, lower construction activity in 2015 resulted in fewer accidents. Then, from 2015 to 2018, construction accidents began to increase. The dip in construction accidents can also be explained by the change in the total number of construction contracts and building construction areas (see Figure 2). Both lines also exhibit the same pattern as the number of construction accidents. The above-mentioned information establishes a relationship between cost, investment, profit and safety within the construction industry. The period from 2011 to 2015 was the 12 th Five-Year Plan of China, during which China expected a shift to a consumption-driven economy [27]. Therefore, China's economic structure was adjusted, and the development model changed from 2010 to 2015, leading to the  
Figure 1: Building and civil construction accidents. deceleration of the construction industry. In this case, the number of construction accidents decreased as well. Construction industry profit improved after 2015 and construction accidents accordingly increased during that period. Additionally, MOHURD published a notification to local authorities prohibiting delay in reporting or concealment of construction accidents in 2015 [28], which also contributed to the increase in accidents after 2015. Number of construction employees increased every year except for 2011 (for example, [22]). Despite the increased number of workers, a decrease in construction accidents indicates that safety improved during that period. Therefore, a combination of economic conditions and safety measures could explain the construction accident change. Figure 3 illustrates total number of construction accidents (during the period from 2010 to 2018) among 31 regions in China (excluding Hong Kong, Macao and Taiwan). Regions with higher GDP, such as Jiangsu Province, Zhejiang Province and Guangdong Province, have the most accidents. Additionally, relatively underdeveloped regions such as Shanxi Province, Ningxia Province and Tibet Autonomous Region have the fewest accidents.