6.1.2. Robustness Test
- (1)
Replacement of core variable measures, and data sources
Corporate capital also serves as an effective indicator reflecting the industrial development capacity of a region. In this study, we utilized corporate capital as a proxy variable for the dependent variable to circumvent the subjectivity in the selection of the dependent variable method that could affect the robustness of the research findings. Column (1) of
Table 3 shows the results of the robustness check regression after changing the measure of the dependent variable. The estimated coefficient for the urbanization rate is significantly positive, indicating that an increase in the urbanization proportion in modern China can enhance corporate capital, facilitate the expansion of modern enterprises adopting large-scale machinery production, and promote industrial transformation and upgrading. Our core findings remain intact, and the selection of dependent variable indicators does not alter the conclusions of this study.
To mitigate the influence of data source selection on our conclusions, we conducted robustness checks by changing the data sources for both the dependent and independent variables. The dependent variable was substituted with data on modern enterprises from 1840 to 1916, collated in the 18th issue of the
Journal of the Institute of Modern History, Academia Sinica. For the independent variable, the urbanization rate, replacement data were drawn from the
Survey Materials of Christianity in China from 1901 to 1920 [
41], which provides urban and total population figures for the year 1918. The regression results reported in Columns (2) and (3) of
Table 3, with the urbanization rate’s coefficient being significant at the 1% level, indicate that urbanization in modern China significantly promotes the increase in the number of modern enterprises, facilitating industrial transformation and upgrading. This suggests that the findings of this study are robust.
- (2)
Replacement sample time span
During World War I (1914–1918), Western capitalist nations, preoccupied with the war, relaxed their economic aggression toward China. There was a sharp decline in the goods exported from China, while the expansion of military needs significantly increased Western demand for Chinese raw materials and military goods. This provided favorable conditions for the development of modern Chinese national capitalism, ushering in a “golden age” for the development of national industry and commerce. To eliminate the impact of this significant historical event, we divided the sample period into two subsamples: pre-WWI (1910–1913) and post-WWI (1919–1927), conducting robustness checks. The regression results are shown in
Table 4. The regression results reported in Columns (1) and (2) of
Table 4 show that the coefficient of urban population level is significantly positive at the 1% level for both periods. This indicates that urbanization had a noticeable promotional effect on the growth of modern enterprises both before and after WWI, affirming the robustness and credibility of the baseline results of this paper.
- (3)
Excluding samples from provincial capitals and Zhili states
To mitigate the potential bias from political factors in our findings, we conducted a robustness check by excluding samples from provincial capitals and directly governed states. As shown in Column (3) of
Table 4, the regression coefficients of the urbanization rate are significantly positive at the 1% level. This indicates that a higher rate of population urbanization is conducive to industrial agglomeration, suggesting that enhancing urbanization levels in modern China positively impacts industrial transformation and upgrading. Hence, the selection of sample prefectures does not affect the baseline results of our study, demonstrating that our core conclusions are robust.
6.1.3. Endogeneity Analysis
The potential reverse causality between urbanization and industrial transformation and upgrading represents an endogeneity problem that this paper addresses. The elevation of urbanization levels can facilitate industrial transformation and upgrading; yet, conversely, industrial transformation and upgrading can also contribute to an increase in urbanization levels. We used the instrumental variable method for causal identification to validate the promotive effect of urbanization on industrial transformation and upgrading.
We used the number of postal roads during the Qing dynasty as an instrumental variable to identify the causal relationship between urbanization and industrial transformation and upgrading. The choice of this instrumental variable was primarily based on the following considerations: In traditional China, post stations served as comprehensive institutions integrating message transmission, logistics transportation, military defense, and official reception. During the Ming and Qing dynasties, there was a developed network of postal routes, with post stations, courier stations, and express posts set up along major water and land routes, forming a complete postal delivery system. Areas with a higher number of postal routes had more convenient transportation and higher population density, which significantly contributed to the prosperity of commerce and trade and the emergence of commercial towns, indicating a correlation between the distribution of postal routes and the level of urbanization. Moreover, the establishment of post stations initially aimed to provide places for changing horses and resting for those delivering government documents and had certain military defense purposes. By the Ming dynasty, a postal route network connecting the north and south of the large rivers was formed, and during the Qing dynasty, China experienced an even more comprehensive postal route system. Since the development of modern enterprises has no direct association with the establishment of post stations, using postal routes as an instrumental variable was feasible.
In the first stage, as shown in
Table 5, the regression coefficient for the number of postal roads is positive and significant at the 1% level, indicating that the number of postal roads has a positive impact on the level of urbanization. In the second stage, the urbanization rate’s regression coefficient is significantly positive, implying that an increase in the urbanization rate favors industrial agglomeration and significantly boosts industrial development, thereby affirming that our core conclusions remain robust. Additionally, tests for the validity of the instrumental variable show that the Kleibergen–Paap rk LM statistic value is 19.362, significant at the 1% level, suggesting that the instrumental variable is identifiable. The Cragg–Donald Wald F statistic value is greater than 10, rejecting the null hypothesis that “the instrumental variable is weak,” which indicates that the choice of postal roads as an instrumental variable is appropriate.
6.1.4. Heterogeneity Analysis
Considering the influences of industry type, business operation mode, and company size, the role of urbanization in industrial structure adjustment may differ. Therefore, we conducted heterogeneity tests by distinguishing among industry types, modes of business operation, and company sizes to identify the diverse effects of population urbanization on the upgrading of industrial structure.
- (1)
Differentiating industry types
The impact of urbanization on the upgrading of different types of industries may vary. We categorized the sample companies into the secondary industry, represented by the industrial sector, and the tertiary industry, represented by the financial sector, to examine the differential effects of urbanization levels on various industries in early 20th-century China, as shown in
Table 6.
It can be observed that the estimated coefficients for urbanization are significantly positive at the 1% level. However, the absolute value of the urbanization regression coefficient in Column (1) is greater than that in Column (2), indicating that the level of urbanization in modern China has a significant promotional effect on industrial upgrading, with a more pronounced impact on the upgrading of the secondary industrial structure. This is likely due to the uneven development of industries in modern China, where the tertiary sector was not yet well established. Although industries such as finance and insurance were emerging, their influence remained weak. In contrast, the secondary industry, predominantly industrial, was flourishing and experiencing a continuous increase in labor demand. The rise in the urban population proportion in modern China had a more notable promotional effect on the development of the secondary industry compared to the tertiary industry.
- (2)
Distinguish the nature of enterprises
Modern enterprises can be categorized into four types according to the nature of ownership and management: government-operated, merchant-operated, joint government–merchant, and Sino-foreign joint ventures. Government-operated enterprises are directly established by the government. Merchant-operated enterprises refer to those founded by individuals or commercial entities, either through sole proprietorship or partnerships. Joint government–merchant enterprises, also known as government-supervised and merchant-managed enterprises, involve a cooperative arrangement between government and private merchants. In this model, the government may provide some financial or policy support, while private merchants contribute capital and manage daily operations. Sino-foreign joint ventures are collaborative enterprises established between Chinese and foreign companies. The impact of urbanization on the development of industries with different operational models may vary. We conducted a heterogeneity test on enterprises with these four different operational methods, and the regression results are presented in
Table 7. The results indicate that the coefficient of urbanization is significantly positive for all types, suggesting that an increase in the level of urbanization significantly promotes the development of industries regardless of their operational model. Looking at the magnitude of the impact, the absolute value of the urbanization coefficient in Column (2) is much larger than in other columns, implying that urbanization has the most pronounced promotional effect on merchant-operated enterprises; the absolute value of the coefficient for urbanization in Column (4) is slightly larger than in Columns (1) and (3), indicating that the impact of urbanization in modern China on the development of Sino-foreign joint ventures is greater than on government-operated and joint government–merchant models; the urbanization coefficients’ absolute values in Columns (1) and (3) are very close, reflecting no significant difference in the impact of urbanization on enterprises with a government element in their operation.
This differentiation could be attributed to the fact that privately owned enterprises operate entirely with private capital, employ workers, and use machinery in production, embodying modern national capitalist enterprises with strong flexibility, profitability, and independence. On the other hand, Sino-foreign joint ventures are modern enterprises established and operated through Chinese and foreign capital collaboration, significantly influenced by Western capitalism throughout their growth and development. Government-operated and government–merchant cooperative enterprises, including those supervised by officials but operated by merchants, are heavily imbued with official characteristics. Government bureaucracy plays a dominant role in the development of these enterprises, which possess less autonomy compared to privately owned businesses. Consequently, urbanization in modern China plays a more prominent role in enhancing the development of privately owned enterprises, has a secondary influence on Sino-foreign joint ventures, and exhibits a weaker effect on enterprises with official characteristics.
- (3)
Differentiating enterprise size
Capital amount serves as a crucial metric for assessing enterprise size, and the impact of urbanization levels may vary across different scales of enterprises. In this paper, enterprises were categorized based on their capital amounts into four types: capital of 10 to 100 thousand, capital of 100 to 500 thousand (excluding 100 thousand), capital of 500 to 1000 thousand (excluding 500 thousand), and capital of 1000 to 10,000 thousand (excluding 1000 thousand). This categorization allows for an exploration of the differential effects of urbanization levels on enterprises of varying sizes in modern China.
Table 8 presents the regression results.
The results demonstrate that the regression coefficients of urbanization are significantly positive at the 1% level across all business sizes, indicating a clear promotional effect of urbanization on industry development regardless of the scale of the enterprise. Furthermore, it is observed that the absolute values of the regression coefficients for urbanization in Columns (1) and (2) are larger than those in Columns (3) and (4), suggesting that the positive impact of urbanization is more pronounced for small and medium-sized enterprises with a capital of 500 thousand or less. This implies that small and medium-sized enterprises in modern China, which have more centralized decision-making processes, are more responsive to market changes, possess simpler organizational structures, and exhibit greater production and management flexibility. The contribution of labor in these enterprises is more easily recognized, allowing urbanization to have a more significant effect on the growth and development of small and medium-sized businesses.
- (4)
Distinguishing between the eastern, central, and western regions
The eastern, central, and western regions of China exhibit significant differences in resource endowments, levels of economic development, social structures, political characteristics, and degrees of openness to the outside world. Consequently, these regions vary in their urbanization and industrial development outcomes. We categorized the samples based on their geographical location into eastern, central, and western regions (as shown in
Table 9) to examine the impact of urbanization on industrial transformation and upgrading in different areas.
Table 10 reports the regression results. The results indicate that the regression coefficient for urbanization in the eastern region is significantly positive at the 1% level in Column (1), while for the central region, it is significantly positive at the 5% level in Column (2). In the western region, it is significantly negative at the 5% level in Column (3). This reflects that urbanization in modern China’s eastern and central regions has a positive impact on industrial transformation and upgrading, with the promoting effect being more pronounced in the eastern region. This might be attributed to the eastern region’s earlier opening to trade, higher level of economic development compared to the central and western regions, and the concentration of national industries, making urbanization more effective in promoting industrial transformation and upgrading. In the case of the western region, due to its lower levels of economic prosperity, urbanization, and openness compared to other regions, along with a significant gap in industrial development, urbanization fails to exert a positive effect.