An Empirical Study on the Impact of Digital Economy Innovation Development on the Export Quality of Chinese Electromechanical Products

Abstract

This study measures the export quality of electromechanical products using data from China’s electromechanical products from 2011 to 2021, empirically investigates the effects of the level of innovation and the growth of the digital economy (DE) on the export quality of electromechanical products, and assesses potential industry heterogeneity. With an erratic upward trend, it is observed that the export quality of Chinese electromechanical products has suffered twice. China’s DE has demonstrated a rising trend in innovation and growth year over year. The creation and growth of the DE throughout the study period had an inverted “U” dynamic effect on the export quality of electromechanical goods, which was initially boosted and later decreased. It is possible to raise the export quality of Chinese mechanical and electrical products by expanding firm size and raising human resource levels. The export quality of Chinese mechanical and electrical products is not much impacted by innovation, R&D capacity, or degree of openness. The inverted “U”-shaped dynamic impacts of the DE’s creation and development on the export quality of electromechanical products are still present after endogeneity analysis and robustness testing, which initially promote and then suppress the rate. The inverted “U”-shaped relationship between DE innovation development and the quality of electromechanical product exports of the manufacture of computers and other electronic equipment, as well as general equipment manufacturing, is still significant, according to the results of sub-industry tests. The study presented in this article offers policy recommendations for facilitating the innovative growth of the DE and raising the standard of electromechanical exports from China.

1. Introduction

Electromechanical items, China’s top export category, are a crucial driver of the country’s high-quality export growth and are becoming increasingly significant to the world economy. Enhancing the overall quality of exports, boosting the efficacy of the nation’s foreign commerce, and extending China’s international opening depends on improving the quality of electromechanical goods’ exports. The Notice of the Ministry of Commerce on Issuing Certain Policies and Measures to Support the Stable Development of Foreign Trade, issued by the Ministry of Commerce of China on 27 September 2022, suggests that full use should be made of the role that cross-border e-commerce may play in stabilizing international trade, and that e-commerce across international borders, overseas warehouses, and other new modes of foreign trade should be jointly supported in their development. The emergence of novel digital technologies and data components, such as artificial intelligence and big data, has fueled the growth of the DE, a significant facilitator of modernization in China. It also offers a fresh path for the export of Chinese electromechanical goods. Since 1994, when China launched its first set of web pages, China has gradually integrated into the wave of the global DE, and the DE in China has largely been divided into two phases: the growth period and the outbreak period. In the early phases of the DE’s growth, China gradually realized a full-featured connection with the Internet, and the construction of Internet infrastructure subsequently gradually improved. The emergence of novel sectors like online banking and e-commerce propelled the DE into a phase of rapid expansion, where the Internet showed a trend of diversification and depth, and the DE achieved leapfrog development from catching up to innovation. In 2016, when the China-led “G20 Digital Economy Development and Co-operation Initiative” was held, China’s digital economy was manifested via a deep inward integration with the real economy, and outwardly actively explored participation in global digital economic governance. Therefore, how is the quality of China’s mechanical and electrical product exports in such a context? Is it possible to improve the quality of Chinese electromechanical exports through the DE? What causes it to have an effect? Is there any industry heterogeneity in the effect of the DE on the export quality of Chinese mechanical and electrical products, considering the continued advancements in digital technology? In terms of theoretical significance, the empirical research on these questions provides us with the possibility of improving the way we measure the growth of DE innovation and supplementing the quantitative research on the DE through an understanding of China’s actual situation, expanding the scale of research on export quality, refining the object of research on export quality, and focusing on analyzing the export quality of electromechanical products. These possibilities enable us to conduct theoretical investigations into the underlying mechanisms linking China’s exports of electromechanical items and the DE, and to serve as a reference for future studies on the export quality of a particular product. In terms of relevance, it can be instrumental to grasp the current situation of China’s electromechanical product exports, explore the effects of DE innovation and growth on the quality of China’s electromechanical product exports, and provide new ideas for realizing the high-quality growth of electromechanical product exports.

2. Literature Review and Impact Mechanisms

2.1. Digital Economy Research

Researchers are currently focusing on the following aspects of the “DE” at this stage: the connotation of the DE [1], characteristics, nature, and impact [2,3], development logic and trend [4], and measurement and driving factors [5,6,7]. With the integrated combination of the DE and the real economy, research results concerning the DE-enabled export trade continue to emerge. For example, Li et al. (2023) argued that the DE contributed positively to an increase in service export competitiveness [8]; Zhang et al. (2022) verified the relationship between e-commerce, technological progress, and urban export trade, argued that the DE could effectively promote export trade through technological advancement, and investigated the variety of effects on export quality caused by the regional DE [9]. In addition, the existing literature on the impact of the DE on export product quality is still relatively small, whereby most studies focus on the DE and the export quality of the whole region or country. For example, Hong et al. (2022) argued that the DE has an impact on the quality of export products through enterprise innovation, and that the risk of digital transformation or digitalization inputs increase when the digitalization capacity of enterprises is low, with a decrease in export quality. Moreover, the authors stated that, when the digitalization level of enterprises improves, it in turn significantly enhances the innovation capabilities of firms, as well as improves their export quality [10]. Lopsided et al. (2023) found that data from major provinces in China indicated a significant improvement in export quality as a result of the DE, and this effect was a significant negative spatial effect [11]. Research has been conducted to empirically examine the relationship between the DE and the quality of exports of manufactured or agricultural goods. For example, Xie et al. (2022) discovered that the DE may significantly improve the export product quality of manufacturing companies by using micro-trade data, pointing out that the driving effect showed some heterogeneity for different ownership firms [12]. Li (2022) explored the mechanisms and challenges of the digital technology revolution on the high-quality growth of China’s manufacturing export trade from the supply and demand side [13].

2.2. Measuring and Influencing Factors of Export Quality

As China’s export commerce expands quickly, more academics are focusing on export quality. Yasar et al. (2022) investigated China’s export structure by utilizing a quadratic function and showed that China’s partner countries’ GDP per capita had an inverted U-shaped relationship that promotes and then increases China’s exports [14]. The empirical research on the factors affecting export quality [15] and upgrading export product quality [16,17] have become increasingly hot issues in the academic field. As product quality cannot be directly observed or measured, the measurement of export quality in the educational area has not been unified, which can be roughly summarized in the following three ways: unit value method [18], export quality index method [19], and demand information backward projection method [20]. Studies have focused on the factors affecting export quality, like government subsidies, financing constraints, per capita income level, innovation capacity, production efficiency, and government tariffs. For example, Anwar and Sun (2018) concluded that foreign direct investment in China’s manufacturing sector could effectively improve the quality of China’s exports. The impact of funding sources for foreign direct investment on the caliber of exports from businesses differs across different locations [21]. Using the instrumental variable approach, Dong et al. (2022) found that intellectual property protection improved export quality [22]. Zhang (2015) contended that there was an enabling and then an obstructing influence in the interaction between financing limitations and the caliber of firm export items [23].

2.3. Mechanisms for the Impact of Innovative Growth of the Digital Economy on the Quality of Exports

First, the creative growth of the DE impacts export quality through the factor enhancement effect. At present, information and data have become vital production factors. The digital infrastructure makes the rapid docking and sharing of massive data possible, broadens the information exchange channels of the factor market, and dramatically improves the effectiveness, timeliness, and transparency of information [24]. By the use of the expanding financing channels of digital technology and platforms, reducing information asymmetry, and accelerating the diffusion of technology and business models, the mobility of factors like capital, labor, and technology have been significantly enhanced [25]. The role of land factors continues to be improved. The input structure of the factors continues to improve, and the elements become increasingly integrated. In particular, the establishment of the virtual digital image has overcome the information blockage between enterprises and their internal sectors, which can achieve the accurate matching of supply and demand factors during the production process so that the factor productivity of electromechanical products can be optimized, and ultimately feed back to the improvement of the quality of electromechanical products export, significantly boosting the industry’s and electromechanical businesses’ ability to compete globally as a whole in turn.

Second, the innovative growth of the DE impacts export quality through the implementation of the enabling effect. Digital economy permeates processes like management, R&D, production, and the trade of electromechanical enterprises in all aspects, and digital technologies and platforms represented by the Internet of Things, artificial intelligence, 5G technology, etc., realize a more comprehensive resource allocation, driving electromechanical products to break through the “low-end locking.” The improving profits work as incentives for enterprises to continue to increase the R&D, promote electromechanical products, and enhance the quality of electromechanical export products. Specifically, when it comes to enterprise management, integrating digital technology and traditional industries will enable enterprises to effectively manage their businesses as they grow. The enterprise’s organizational structure gradually achieves “network” and “flat” development, optimizing internal control. Managers can receive timely feedback and product implementation information from grassroots employees to make decisions for the first time. “Flat” and “network” organizational structures also enable grassroots employees to receive the management of the product adjustment program quickly so as to make corresponding adjustments to the R&D, production, and trade of the products, and to ensure the supply of electromechanical products. In R&D, the digital platform optimizes the supply chain and value chain, replaces physical intermediaries with virtual intermediaries, innovates the bilateral market exchange mechanism, promotes the continuous iteration of innovative technologies, realizes fusion innovation, continuously extends the boundaries of creative activities, achieves accurate R&D, improves the effectiveness of creation, and consequently improves the quality of electromechanical product exports. In production, the DE can use the self-growth characteristics of digital technology, especially by applying the intelligent supply chain. Digital technology spawned from the platform economy, network economy, and other digital economic forms, which can reduce enterprise production costs and transaction costs [26] as well as force some low-value-added, low-efficiency electromechanical enterprises to carry out digital upgrading and transformation, which exert a positive impact on the quality of electromechanical products. In the trade process, digital technology can promote the traceability of technology and services so that electromechanical enterprises can break through the international trade field of pre-sale and post-sale investigation methods, improving logistics and delivery efficiency, producing according to sales, and reducing inventory.

Third, export quality is impacted by the offsetting effect of the DE’s inventive growth. However, e-commerce also negatively affects the quality of electromechanical product exports. Through the advantage of predominance, the DE easily forms a market monopoly, likely exacerbating the imbalance in the value chain distribution, resulting in the diseconomies of the scale of electromechanical enterprises. When production factors such as capital, information, labor, and technology exceed the optimal critical value of aggregation, resource mismatch occurs, which is further aggravated by the vicious competition among electromechanical enterprises for production factors. The scarcity of various production factors will inevitably increase the production costs of enterprises. If other conditions remain unchanged, the increase in production costs will cause electromechanical enterprises to rethink resource allocation and control or reduce technological innovation expenditures, thus hindering the technological progress of electromechanical enterprises, productivity enhancement, and international market competitiveness, which then consequently imposes a counteracting effect on upgrading export quality and reduces the impact of the DE’s engine on the premium expansion of electromechanical items.

Summarizing the above analysis, the DE’s innovative growth will impose a comprehensive impact on the quality of electromechanical products’ exports through the factor-upgrading effect and the implementation of the enabling impact and the offsetting impact, which is, however, uncertain. In the next section, we will study how the DE’s innovative growth influences the export quality of electromechanical products using electromechanical product data.

3. Research Design

3.1. Measurement of Export Quality of Electromechanical Products

Academic approaches to measuring export quality are broadly summarized as the unit value approach, the export quality index approach, and the demand information backcasting approach. Considering the advantages and disadvantages of each method, this essay utilizes the methodology of Li and Wang (2013) [27] and determines the export quality of electromechanical items using the unit value technique. The unit value method can not only compare the status of different products in the electromechanical industry, but also sum up the quality of export products in different industries.

$$EQ={\displaystyle \sum {}_j\frac{T{V}_j}{{\displaystyle \sum {}_{j}T{V}_j}}}\frac{T{V}_j}{Q_j}$$

(1)

In the formula, EQ is the export quality of the electromechanical industry. TV_j is the export value of the jth product in the E&E industry. Q_j is the export quantity of the jth product in the E&E industry, representing the export share and unit value of the jth product in the E&E industry.

3.2. Measurement of the Level of Innovative Growth of the Digital Economy

The signs and techniques for gauging the degree of innovation and advancement of the DE remain up for debate among academics. With regard to this, based on the definition of the DE in the Global Digital Economy White Paper, the DE is to use the network as the carrier, use digital technology as the driving force, utilize the combination of the real economy and digital technology, and continuously promote the development of the economy in the direction of digitization and intelligence. The extension of the reach of digital technology’s information transmission is the primary manifestation of DE “innovation” and the DE innovation to the business model, which is a horizontal concept within the DE. The DE “innovation” mainly reflects the expansion of the scope of information dissemination via digital technology and the innovation of business models through the DE, which is a horizontal concept within the DE, whereas the DE “development” is a vertical concept, which refers to the DE trend in each year, and the change from year to year. Combined with the actual situation of China’s DE innovation and growth and the research results of relevant scholars [28], the objective of this paper is to build a comprehensive system of evaluation indexes to measure the level of innovation and growth within the DE, which is composed of three first-level indexes and seven second-level indexes (see

Table 1. Evaluation index system for the level of innovation and growth of the digital economy.

Level 1 Indicators	Level 2 Indicators	Indicator Properties	Data Sources
Digital Infrastructure	Number of Internet broadband access subscribers	+	China Statistical Yearbook
	Cell phone subscribers at the end of the year	+	China Statistical Yearbook
Digital Industrialization	Total telecommunication services	+	China Statistical Yearbook
	Number of employees in the information communications, computer services, and software industry	+	China Statistical Yearbook
	Revenue from software operations	+	China Statistical Yearbook
Industrial Digitization	Digital Inclusive Finance Index	+	China Statistical Yearbook
	E-commerce turnover	+	China Statistical Yearbook

+ denotes that the indicator number is positive.

). Among them, digital infrastructure is the basis for the innovative growth of the DE. Digital industrialization represents the leading industries in the DE, such as the telecommunications, software, and information technology services industries, which reflect the iterative innovation of digital technology. Industrial digitization is the engine of China’s DE innovation and growth. The entropy method is applied in this study to objectively standardize and assign weights. The consequences are multiplied by each indicator’s corresponding data to measure the DE’s total innovation and growth level.

3.3. Models, Variables, and Data

3.3.1. Model Setting

Considering that the impacts of the level of innovation and growth of the DE on the export quality of electromechanical products may be uncertain and that there may be a nonlinear relationship between the two, this paper introduces the quadratic term of the level of innovation and growth of the DE into the model, and the model is set as follows:

$$\begin{array}{l}\ln E{Q}_t=C_1+{\beta }_{1}D{E}_t+{\alpha }_1{(D{E}_t)}^2+{\beta }_2\ln \mathrm{s}iz{e}_t+{\beta }_3\ln inn{o}_t\\ +{\beta }_{4}ope{n}_t+{\beta }_5\ln huma{n}_t+{\mu }_t\end{array}$$

(2)

where ln denotes the logarithm. The subscript t is the year. C₁ is a constant term. DE_t is the level of innovation and growth of the DE. (DE_t)² is the quadratic time of DE_t. To further improve the reliability and robustness of the model, referring to the study of Yu et al. (2021) [29], enterprise size (size), innovation and R&D capability (inno), openness (open), and human capital (human) are used as control factors. These are the coefficients of the explanatory variables and the coefficients of the control variables. ${\mu }_t$ represents the random disturbance terms.

3.3.2. Explanation of Variables and Data

• Explained Variables

The explanatory variable used in this article is the export quality of China’s electromechanical goods (EQ_t). E&E products belong to categories 84 to 91 in the HS Customs Code (1996). The export amount and quantity of each type of electromechanical product for 2011–2021 needed to calculate the export quality of electromechanical products are obtained from the CEPII-DATA database. To calculate the export value and quantity of each type of Chinese E&E product, the STATA 17.0 software was used to summarize each type of Chinese E&E product, filter the data of Chinese E&E products, and finally add up the export value of the same product exported to all countries. As the types of exported electromechanical products from 2011 to 2021 are different, and the types of exported products show a trend of gradual decrease, by comparing and screening the HS codes that do not correspond to the product codes in each year and eliminating the products whose export amount and export quantity are 0, about 82 products can be eliminated, leaving 1060 types of products.

• Core Explanatory Variables

This paper takes the innovative growth of the digital economy (DEt) as the primary explanatory variable. The China Statistical Yearbook is the source of all indicator data on the status of innovative growth of the DE. Among them, the digital inclusive finance index and e-commerce sales jointly published by the Digital Finance Institute of Peking University and Ant Gold Service Group are selected to measure industrial digitization.

• Control Variables

The enterprise’s size (size) is determined by taking the logarithm of its personnel count. Clarke (2006) [30] found a positive correlation between the labor force and the quality of exports, and the quantity of the labor force has a particular impact on the quality of export products. The logarithm of the number of patent applications measures innovation and R&D capability (in no.). Innovation and R&D capability can promote the quality of China’s mechanical and electrical product exports by enabling enterprises to acquire technology and talents through local R&D. The ratio of the total import and export commerce to GNP represents the degree of openness (open), with larger values indicating a higher degree of transparency. The higher the degree of transparency in China, the more favorable the export of electromechanical products. Electromechanical enterprises obtain opportunities for technological exchange in the export trade. Knowledge and technology spillover improve the efficiency and quality of product production, thus improving the quality of electromechanical product exports. The logarithm of the total number of students enrolled in regular undergraduate programs is used to indicate human capital (human). Technical work tasks and the importance of cognitive, learning, and social skills for electromechanical enterprises have been further emphasized. Highly skilled laborers with higher education or specific skills can gain a more vital comparative advantage and increase the absorption capacity of “technological spillovers” from foreign investment, which is beneficial for expanding the labor market and improving the quality of labor exports. The absorption capacity of foreign capital “technology spillover” is improved, which helps to deepen the division of labor and improve production efficiency. Therefore, higher-quality human capital gain from electromechanical product technology advancements, which can enhance the export quality of electromechanical products. The descriptive statistics of the main variables are listed in

Table 2. Descriptive statistics of the main variables.

Variables	Number of Observations	Average Value	Standard Deviation	Minimum Value	Maximum Values
lnEQ	11	5.480	0.354	4.821	5.927
DE	11	0.398	0.302	2.18 × 10−5	0.914
(DE)2	11	0.241	0.282	4.75 × 10−10	0.836
inside	11	11.28	0.00745	11.26	11.29
lninno	11	14.98	0.393	14.31	15.47
open	11	0.374	0.0607	0.318	0.484
inhuman	11	7.918	0.130	7.744	8.159

.

4. Analysis of Empirical Results

4.1. Analysis of the Quality of China’s Exports of Electromechanical Products

Figure 1 depicts the trend of China’s export quality of electromechanical products from 2011 to 2021. The y-axis represents the quality of China’s exports of electromechanical products. From 2011, it shows an overall fluctuating upward trend. The export quality of China’s electromechanical products declined from 2015 to 2016. The decline was not dramatic due to the global economic downturn, the slowdown in world trade, and the rise in domestic costs. Meanwhile, the developed countries rely more on their electromechanical products, shortening the global supply chain and significantly reducing the overall trade in intermediate goods. The export quality of China’s electromechanical products declined for the second time from 2015 to 2016. The decline can be first attributed to preventing and controlling the domestic new crown epidemic. The production capacity of electromechanical products returned slowly, which triggered the difficulties encountered by electromechanical products export. Secondly, China’s electronic product exports declined because of the severe epidemic of the central exporting countries, such as the U.S., Japan, South Korea, and Germany. Due to the resilience of China’s exports, the export quality of electromechanical products in 2020 is still higher than that in 2018.

4.2. Analysis of Digital Economy Innovation Development Level

As shown in

Table 3. Measurement results of comprehensive evaluation indicators of innovation and growth of the DE in 2011–2021.

Year	Level of Innovation and Growth in the Digital Economy	Rate of Increase in the Degree of Innovation and the DE’s Development
2011	0.0000218	/
2012	0.0643877	295,256.42%
2013	0.1569259	143.72%
2014	0.2068774	31.83%
2015	0.2744102	32.64%
2016	0.3053119	11.26%
2017	0.4126072	35.14%
2018	0.5979693	44.92%
2019	0.6618732	10.69%
2020	0.7787408	17.66%
2021	0.9144648	17.43%

, the results, obtained from measuring the level of innovative growth of the DE, show an overall upward trend of the level of innovative growth in China from 2011 to 2021. Regarding the growth rate of DE innovative growth level, the growth rate from 2011 to 2012 reached 295,256.42%, indicating that the DE innovative growth level was in a period of high growth from 2011 to 2012. From 2013 to 2021, the growth rate of the innovation and growth level of the DE shows a downward trend in fluctuation.

4.3. Analysis of Benchmark Regression Results

The regression of model (2), the regression findings between China’s exports of mechanical and electrical items, and the degree of innovative development in the DE are displayed in

Table 4. Benchmark regression results of the level of innovation development of the DE and the quality of China’s mechanical and electrical products exports.

Variables	lnEQ
	(1)	(2)
DE	2.956 ***	2.450 **
	(7.54)	(4.08)
(DE)2	−2.169 ***	−1.879 **
	(−5.18)	(−4.47)
inside		8.197 *
		(2.14)
Encino		−0.637
		(−1.80)
open		−1.265
		(−1.21)
inhuman		2.272 ***
		(5.79)
Constant	4.827 ***	−95.455
	(68.11)	(−2.05)
Observations	11	11
R-squared	0.937	0.995
F test	1.54 × 10−5	0.000146
r2_a	0.922	0.988
F	59.86	134.3

Note: In the table, “***”, “**”, and “*” represent passing the test at the 1%, 5%, and 10% significance levels, respectively, where the values in parentheses represent t-statistics.

.

The outcome in Column (1) is the absence of any control variables. DE innovation and growth has a positive main coefficient and a negative secondary coefficient. At the 1% confidence level, the significance test has been passed by both the primary and secondary coefficients, which shows an inverted U-shaped relationship between the DE innovation and growth and the quality of China’s electromechanical product exports.

Column (2) of Table 4 shows the regression results by introducing control variables. It can be seen that with the introduction of different control variables, such as enterprise size, innovation and R&D capability, openness, and human capital, the coefficient of the primary term of the level of innovation and growth of the DE is always positive and the coefficient of the secondary duration is always negative. The coefficients of the primary and secondary terms are relatively stable and pass the significance test. The economic significance of the data suggests that the level of digital financial innovation and growth will have an inverted “U”-shaped impact on the quality of China’s exports of electromechanical products, that is, there is an “inflection point.” As for the estimation results in column 2 of Table 4, according to the algorithm of the symmetry axis of the quadratic function, the following can be determined:

$$\mathrm{DE}=-2.450/\left[2\ast (-1.879)\right]=0.6519$$

(3)

The inflection point of the inverted “U” type may be easily found. When the DE’s innovation and growth level is lower than 0.6519, it will promote the export quality of China’s mechanical and electrical products. When the level of digital economic innovation and growth reaches the “inflection point”, it will inhibit the mechanical and electrical products’ export quality upgrade to a certain extent. The possible reasons for this inverted “U” dynamic impact are as follows: before the DE innovation and growth level reaches the inflection point, the DE has been widely used in many fields. As a result of the growth of digital infrastructure, the channels of information exchange in the factor market have expanded. The production factors of China’s electromechanical products are more closely integrated, and the factor enhancement effect gradually appears. At the same time, the information communication efficiency of electromechanical enterprises in management, R&D, production, and trade has increased, increasing the productivity of businesses while lowering average and transaction costs. The marginal benefit has been growing, with the degree of specialization improving to realize the economy of scope and economy of scale, and the quality of electromechanical product export has been improved, which has recognized the penetration and empowerment effect. However, when the level of innovation and growth of the DE is over the “inflection point”, the offset impacts on the export quality of electromechanical enterprises become increasingly prominent. The DE makes it easy to bring about the oligopoly and monopoly market structures of electromechanical products through the dominant advantage. Some electromechanical enterprises that are highly dependent on the traditional mode of production and operation face a significant threat under the enormous impacts of the DE. Some monopoly enterprises will even use improper means to hinder the development of other electromechanical product enterprises, disrupting the regular market order, resulting in the diseconomies of scale of electromechanical enterprises and exacerbating the mismatch of resources. The scarcity of production factors has increased the production cost of the enterprise, leading to a decline in the enthusiasm for research and development of the enterprise to control or reduce the expenditure on technological innovation, which is detrimental to the quality improvement of electromechanical gas pressure export. In addition, when the price of electromechanical products of the same quality increases, enterprises will choose a low-price penetration strategy, which is also unfavorable for the overall quality improvement of electromechanical products being exported.

As a result of the regression analysis of control variables, the enterprise size is significantly positive at a significance level of 10%, which indicates that the export quality of Chinese electromechanical products will increase by 8.197% for every 1% increase in enterprise size. The export quality of Chinese electromechanical goods will rise by 2.272% for every 1% increase in the number of students enrolled in general undergraduate programs, since human capital is considerably positive at the 1% significance level. Digital technology realizes electromechanical products’ value creation and technical revitalization, accelerating human capital accumulation. At the same time, the higher level of human capital is more adaptable to the technological upgrading of electromechanical products, which promotes improving the quality of China’s electromechanical product exports. The regression coefficients of innovation and R&D capability and openness do not pass the statistical significance test, indicating that innovation and R&D capability and transparency do not substantially impact the export quality of China’s mechanical and electrical products.

4.4. Endogeneity Analysis

The DE innovation and growth affect the quality of electromechanical products’ exports to a certain extent. At the same time, the export quality of China’s electromechanical products also affects the level of innovation and growth of the DE to a certain extent and there may be a mutual causal relationship between the two. In addition, many factors may affect the quality of China’s electromechanical product exports. Based on the availability of data, this paper may have the problem of omitted variables in the model setting. This work estimates the endogeneity of the model using the lagged variable approach in order to manage the endogeneity issue brought on by missing variables and reverse causality. Regression analysis is performed on the lagged-one-period level of innovation and growth in the DE and the quadratic term of the lagged-one-period level of innovation and growth in the DE. Based on

Table 5. Endogeneity test.

Variables	lnEQ2
DE	2.565 **
	(3.52)
(DE)2	−1.894 **
	(−3.75)
inside	7.444
	(0.77)
Encino	−0.000000210
	(−0.92)
open	−0.665
	(−0.40)
inhuman	2.505 **
	(3.20)
_cons	−97.91
	(−0.93)
N	10
r2_a	0.977
F	64.72

Note: In the table, “**” represents passing the test at the 5% significance level, where the values in parentheses represent t-statistics.

, the regression results are still significant at a level of 5% confidence; the regression coefficient of the lagged term of the level of digital economic innovation and growth is significantly positive, while the regression coefficient of the lagged period of the quadratic time of the level of digital financial innovation and growth is particularly harmful. There is no apparent reversal of significance, and even if endogeneity is taken into account, there is still a sizable inverse “U”-shaped association between the quality of China’s exports of electromechanical items and the degree of digital economic innovation and growth. The inflection point is close to the location of the inflection point obtained from the benchmark regression above.

4.5. Robustness Tests

4.5.1. U-Test

Adding the square term of the level of the DE’s innovation and growth in the model may misjudge the curve of monotonous inflection to the origin as an inverted “U” curve, so the U-test curve must be carried out. As shown in

Table 6. U-test.

U-Test	Coef
t-value	4.08
P	0.00757

, the t-statistic is 4.08, which passes the test at a significance level of 1%, indicating that the relationship between the level of creative growth of the DE and the export quality of China’s electromechanical products is still inverted “U” shape.

4.5.2. Substitution of the Explanatory Variable Computation Method

Since different estimation results may be obtained by choosing other evaluation index systems for the level of innovation and growth of the DE, to test the robustness of the estimation results, the method of measuring the level of innovative growth of the DE must be regressed again. As shown in

Table 7. Robustness test.

Variables	lnEQ
	(1)	(2)
DE	3.096 ***	1.920 **
	(7.30)	(3.68)
(DE)2	−2.320 ***	−1.532 **
	(−5.31)	(−4.06)
labor		8.834 *
		(2.18)
Encino		−0.561
		(−1.51)
open		−2.046
		(−1.75)
inhuman		2.296 ***
		(5.49)
Constant	4.838 ***	−103.531
	(62.07)	(−2.10)
Observations	11	11
R-squared	0.920	0.994
F test	4.07 × 10−5	0.000185
r2_a	0.900	0.986
F	46.09	118.8

Note: In the table, “***”, “**”, and “*” represent passing the test at the 1%, 5%, and 10% significance levels, respectively, where the values in parentheses represent t-statistics.

, the quality of China’s exports of electromechanical products and the degree of innovation and growth of the DE pass the test at a significance level of 1% when no control variables are added. The primary term is significantly positive, while the secondary term is extremely negative; when the control variables are added, there is a significant correlation between the level of innovation and growth of China’s digital economy and the quality of its electromechanical exports at a significance level of 5%. The primary term is significantly positive, while the secondary duration is very harmful, and the DE’s innovation and growth level is very positive. When control variables are added, the regression coefficients of the main study subjects pass the test at a significance level of 5%, with the primary term significantly positive. Additionally, the secondary period is quite damaging. The degree of innovation and growth of the DE is correlated with the export quality of China’s mechanical and electrical products in an inverted U-shaped connection.

4.6. Analysis of Industry Heterogeneity

Estimation results based on the full sample show that the impacts of the level of innovation and growth of the DE on the export quality of electromechanical products can be characterized by an inverted “U”-shaped dynamic. Then, is there any difference in this inverted “U”-shaped characteristic for the subsectors of electromechanical products? According to the National Economy Industry Classification and HS Customs Code comparison match, the whole of the electromechanical industry can be divided into six significant sub-sectors: general equipment manufacturing (x1); special equipment manufacturing (x2); transportation equipment manufacturing (automobile manufacturing, railroad, shipbuilding, aerospace and other transportation equipment manufacturing) (x3); electrical machinery and equipment manufacturing (x4); communications equipment, computers, and other electronic equipment manufacturing (x5); and instrumentation, cultural, and office machinery manufacturing (x6). This paper investigates the impacts of the level of innovation and the growth of the DE on the export quality of China’s electromechanical sub-industries from these six dimensions.

Based on the estimation results for the core variables in

Table 8. Heterogeneity test.

Variables	(1) lnx1	(2) lnx2	(3) lnx3	(4) lnx4	(5) lnx5	(6) lnx6
DE	1.936	−4.131	−2.942	5.359	3.058 ***	1.580
	(1.80)	(−1.23)	(−0.41)	(1.53)	(5.78)	(0.39)
(DE)2	−1.620 *	2.055	1.461	−3.817	−2.365 ***	−1.544
	(−2.16)	(0.88)	(0.29)	(−1.56)	(−6.39)	(−0.54)
inside	−11.365	34.332	−3.126	−1.923	7.088	−16.509
	(−1.66)	(1.61)	(−0.07)	(−0.09)	(2.10)	(−0.64)
lninno	−0.912	2.784	1.155	−2.396	−0.851 *	−1.787
	(−1.44)	(1.41)	(0.27)	(−1.16)	(−2.73)	(−0.75)
open	−7.546 **	3.626	−6.065	−2.513	−1.189	−10.999
	(−4.05)	(0.62)	(−0.49)	(−0.41)	(−1.29)	(−1.56)
lnhuman	−1.601 *	−2.049	−3.778	1.514	2.740 ***	0.055
	(−2.28)	(−0.94)	(−0.81)	(0.66)	(7.93)	(0.02)
Constant	160.444	−409.462	54.389	48.684	−83.009	220.977
	(1.93)	(−1.57)	(0.10)	(0.18)	(−2.02)	(0.70)
Observations	11	11	11	11	11	11
R−squared	0.966	0.796	0.527	0.584	0.997	0.674
F test	0.00662	0.187	0.645	0.552	6.11 × 10−5	0.394
r2_a	0.915	0.489	−0.181	−0.0395	0.992	0.185
F	18.95	2.597	0.744	0.937	207.8	1.378

Note: In the table, “***”, “**”, and “*” represent passing the test at the 1%, 5%, and 10% significance levels, respectively, where the values in parentheses represent t-statistics.

, it can be seen that the inverted U-shaped relationship between innovation and growth in the DE and the manufacturing of general equipment, computers, and other electronic equipment still produces a substantial amount of export quality products. The quadratic term’s coefficient is still noticeably negative. The inverted U-shaped relationship between the level of innovation and growth of the DE and the export quality of other major industries is insignificant.

In terms of control variables, innovation and R&D capability as well as human capital have regression coefficients that are significant in regard to the export quality of electromechanical products in the computer and other electronic equipment manufacturing industries, respectively. As for the export quality of the general equipment manufacturing industry, the regression coefficients of human capital and degree of openness passed the significance levels of 5% and 10%, respectively. It demonstrates that, with regard to each respective industry, the degree of innovation and growth of the DE is inversely correlated with the export quality of the computer and other electronic equipment manufacturing industry and the general equipment manufacturing industry.

4.7. Research Analysis and Conclusions

From China’s electromechanical product export quality to the temporal evolution and measurement features of the inventive growth of the DE, the export quality of China’s electromechanical products has experienced a two-fold decline in an overall fluctuating upward trend. The growth level of China’s DE innovation increased during the sample period.

In terms of the relationship between the quality of China’s exports of electromechanical products and the level of innovation and growth of the DE, the level of innovation and growth of the DE has an inverted “U” dynamic impact on the export quality of Chinese mechanical and electrical products, i.e., there is an “inflection point”, before which the DE’s innovation and growth level promotes the export quality of mechanical and electrical products but inhibits it after the point. In the research interval, through the impacts of the implementation of empowerment and factor enhancement, the early stages of the emergence of the DE promote the transfer of skills and technologies between businesses and geographical areas. The allocation efficiency of the factors of electromechanical enterprises in management, research, growth, production, and trade is improved. The production cost is reduced, thus realizing the economy of scope and economy of scale and improving the quality of electromechanical products export. When the level of digital economic innovation and growth exceeds the inflection point, the offset effect becomes more and more significant, and the level of digital financial creative growth has an inhibiting impact on improving the quality of China’s electromechanical product export.

Regarding control variables, upgrading the scale of enterprises and improving human capital is conducive to developing the export quality of China’s electromechanical products. Chinese mechanical and electrical export quality is not substantially affected by innovation and R&D capability.

The relationship between the level of innovative development of the DE and the quality of the exports of electromechanical products based on the type of the electromechanical industry, as well as the inverse “U” relationship between the level of creative growth of the DE and the export quality of electromechanical products are heterogeneous, indicating that there are different patterns of influence of creative growth of the DE on the export quality of the segmented industries for mechanical and electrical products. Among them, the inverted U-shaped relationship between the level of creative growth of the DE and the export quality of the computer and other electronic equipment manufacturing industries as well as the general equipment manufacturing industry is significant.

5. Discussion

5.1. Academic Implications

This paper develops corresponding economic measures from the perspectives of DE and electromechanical product export, providing new ideas and programs. Exploring the effects and mechanism of the DE on the export quality of electromechanical products, combined with the results of empirical research, provides targeted policy insights and refined practical directions for improving China’s electromechanical product export quality.

5.2. Management Significance

This paper will provide specific policy insights for the improvement of the quality of China’s electromechanical product exports from both the government and electromechanical enterprises. The government should coordinate and deploy the inputs of the DE and regulate its innovation and growth level. It should coordinate the relationship between various fields within the DE, rationally guide the development of new digital infrastructure industries in light of the actual situation, grasp the new kinetic energy of the DE to promote the high-quality development of the electromechanical industry, and entirely release the factor-enhancing effect and enabling effect of the DE. It is also essential that the government strengthens incentives for electromechanical business research and development, protects intellectual property rights, and fosters a climate that guarantees a just and orderly market. Meanwhile, the government should increase investment in human capital, encourage innovative development and entrepreneurship education in colleges and universities, and comprehensively cultivate high-quality, innovative electromechanical professionals. It is intended to support the development of a high-quality vocational education system and accelerate the building of a contemporary vocational education system by merging industry and education. It also ought to avoid homogenization in the process of upgrading the digitalization of electromechanical products, vigorously support the development of electromechanical strategic emerging industries, optimize the export structure of electromechanical products, and strive to guide the coordinated development of various industries by taking the innovative growth of the DE as an opportunity.

For electromechanical enterprises, electromechanical enterprises should accelerate the digital transformation and upgrading, deepen the digital application of management, research and development, production, trade, and other aspects, and create an open system for the digital marketing of electromechanical products. Enterprises are also encouraged to focus on improving the level of the workforce, strengthening the cultivation of vocational skills and professional quality of existing employees, helping to complete the digital transformation as soon as possible, and supporting China’s electromechanical product quality upgrade. Various electromechanical product industries are expected to apply emerging digital technologies to improve sectors’ synergistic ability and intelligence levels.

5.3. Limitations and Future Prospects

This study still has some shortcomings. Firstly, this article makes the case that China’s electromechanical export quality and the DE have an inverse U-shaped relationship. However, it only explains this theoretically and fails to provide specific empirical evidence to analyze how the DE affects the export quality of Chinese mechanical and electrical products. Secondly, this paper finds that there is an inflection point of the DE on the export quality of Chinese mechanical and electrical products, i.e., there is a maximum value of the promotion effect of the DE on the export quality of Chinese mechanical and electrical products. Before the inflection point of the DE innovation and growth for all electromechanical products’ export quality is able to have a role in promoting the quality of future exports of electromechanical products, there must be a more intelligent regulation of the DE so as to allow for the continual increase in the inflection point of the quality level of electromechanical product export. Moreover, a targeted development of the DE can maximize the quality of electromechanical products to promote exports of electromechanical products. To date, no systematic analysis of how the DE reaches this maximum value exists. In the future, further research can be conducted on how the DE can develop to promote the improvement of the export quality of electromechanical products to regulate their export quality intelligently. Finally, to ensure the completeness and continuity of the data to the greatest extent possible, this study only selects China as the overall research object, and the time aspect is also chosen only from 2011 to 2021; but future research can further refine the research sample and time scope, and select data from an urban element to analyze the DE and the quality of electromechanical product exports.