The Policy Evolution Characteristics of Regional Integration Development in the Yangtze River Delta: A Quantitative Analysis Based on Policy Texts from 2003 to 2022

Abstract

The systematic analysis of policy texts on promoting regional integration in the Yangtze River Delta region is of great significance for promoting higher-quality development of this Chinese region. By collecting 803 policy texts from 2003 to 2022 and using policy text and social network analysis methods, we statically reveal the evolution patterns of integration policies in the Yangtze River Delta under different dimensions. According to our research, the types of policies for integration in the Yangtze River Delta are diverse and flexible, with agreement policies being the main focus; the number of annual policy releases shows a trajectory of first fluctuating and then stabilizing growth; policy makers are mainly based on multi-department joint formulation across departments, levels, and administrative regions, supplemented by individual provinces and cities under the guidance of the central government; the integration coverage rate is gradually increasing, but there are differences in the level of emphasis within the field and among provinces and cities; and there is an imbalance in the use of both policy tools as a whole and sub-tools. Based on this, while prioritizing the integrated development of ecology, technology, economy, and other fields, while also promoting comprehensive integration in education, law, information, food safety, and other fields; policy makers should appropriately increase the use of contractual economic tools, maintain the current use trend of structural forcing tools, and enhance the stability of the use of interactive impact tools to ensure the balance and effectiveness of the use of policy tools.

1. Introduction

Regional integration has recently been the style of the day and an unavoidable social development trend amid rapid social growth and frequent international contacts in a variety of places [1]. Especially with the further development of integration organizations in developed Western capitalist countries, regional integration has attracted attention from the international political and academic circles [2]. From a global perspective, regional integration, as the main avenue for independent countries and regions to participate in global competition, has become an undeniable force [3] and an essential stage in entering the process of globalization [4,5,6].

In the era of global regional integration, China has also joined this trend and is actively engaged in its practice and exploration [7]. Now, it has become an essential policy strategy for China to coordinate regional development [8]. Since the reform and opening up, China has implemented regional policies and planned dozens of regions, including the Pearl River Delta region, the Yangtze River Delta region, and the Beijing Tianjin Hebei region. Each region has achieved varying degrees of development. Relative to many regions in China, the cities in the Yangtze River Delta region are geographically close, closely related, and culturally connected, making them good candidates for regional integration and development in China. Throughout the process of promoting regional integration in the Yangtze River Delta, the scope of the region has been expanding for 40 years. Initially established in 1982, the Yangtze River Delta Economic Zone centered around Shanghai, and consisted of only 10 cities. By 2003, the Yangtze River Delta Urban Agglomeration had formed, including 16 cities within the region, and regional cooperation in the Yangtze River Delta began to achieve platformization and scale. Finally, in 2018, the three provinces and one city in the Yangtze River Delta jointly formulated the “Three Year Action Plan for Integrated Development of the Yangtze River Delta Region (2018–2020)”. The coverage of cooperation expanded to 41 cities in the region, achieving full coverage of the Yangtze River Delta region. The Yangtze River Delta has been continuously promoting and exploring regional cooperation, reflecting the new trend of China’s spatial reconstruction since the turn of the 21st century [9].

In fact, the integration strategy of the Yangtze River Delta has already followed a development path with Chinese characteristics that has been tested through practice [10]. First, the Yangtze River Delta region itself has unique geographical conditions, and it is located in the most active developing region in eastern China, including Jiangsu, Zhejiang, Shanghai, and Anhui. It is also the intersection of the Yangtze River Economic Belt and “the Belt and Road”, and it is the world’s sixth-largest urban agglomeration. Second, the strategic position of the Yangtze River Delta region is crucial. Since the Yangtze River Delta region’s integration rose to a national strategic level in 2018, the National Development and Reform Commission issued the “Outline of the Yangtze River Delta Regional Integration Development Plan” in 2019, clarifying the strategic positioning of the Yangtze River Delta region, which is to become a strong growth pole for national development and a high-quality leading model area, taking the lead in realizing modernization and integration, becoming a new model for national reform and openness in the new era. This strategic positioning provides development opportunities for promoting regional integration in the Yangtze River Delta. Unfortunately, there are also many bottlenecks in promoting integration in the Yangtze River Delta [11]. For example, the road connecting Jiangsu and Zhejiang provinces to Shanghai has not yet been fully connected, and the Yangtze River Delta region has not carried out reasonable division of labor in industrial development, which has caused the problem of industrial isomorphism that needs to be solved urgently. The aforementioned problems show that the Yangtze River Delta region’s integration development has not yet been enhanced and needs to be improved. The key to improvement ultimately lies in policy support, which can fully mobilize all resources to participate in regional construction and achieve regional development [12]. Therefore, in order to achieve the Yangtze River Delta’s integration policy aims, corresponding policy tools and methods must be utilized. Based on this, it is necessary to study the development status of integration in the Yangtze River Delta from a policy perspective. This will not only help promote the Yangtze River Delta’s high-quality integration and increase the region’s global competitiveness, but also has reference value for the development of other regions in the country through their own policy formulation and institutional exploration.

2. Literature Review

This study mainly studies regional integration from two aspects; one is the international dimension of regional integration, such as ASEAN and EU integration [13,14]. The other is the domestic dimension of regional integration, such as the integration of the Yangtze River Delta and the Pearl River Delta [15,16]. These two levels of regional integration are essentially the same, as both consist in the process of free movement of production factors and goods between different regions within the region in order to achieve common regional development [17]. After analysis, foreign and domestic research on regional integration mainly involves concepts, effects, measurements, development paths, and related policy analysis.

First, the notion of regional integration has not been well defined by the academic community, and different fields have their own focus in defining it [18]. The practice of regional integration originated from the field of foreign trade, and its concept often refers to regional economic integration. Tinbergen proposed the phrase “regional economic integration” first, pointing out that it is an economic means of capitalist dumping of surplus products, and a process of eliminating artificial obstacles to international or regional economic development and establishing economic structures [19]. On this basis, according to Balassa, regional integration is not only a process of eliminating economic disparities among countries, but also a state of increasing communication and cooperation between regions, based on two perspectives: “state” and “process” [20]. Zhu believes that regional economic integration is a state in which enterprises optimize resource allocation through the market to achieve industrial coordination and talent exchange [21]. Meng pointed out that regional economic integration is essentially a market-oriented process in which independent countries or regions’ economic entities obtain benefits [22]. The diversification of trade and investment has led to a progressive strengthening of international economic ties, and a mainstream trend has emerged in relevant research to interpret the connotation of regional integration from five levels: common market, free trade zone, economic alliance, customs union, and political alliance [23,24,25,26]. However, with the increasing importance of regional integration, it is no longer limited to the economic field. New regionalism, new institutional economics, etc., have deepened the understanding of regional integration [27,28,29,30]. Some scholars have begun to extend the connotation of regional integration to institutional and cultural perspectives [31,32,33]. For example, scholars such as Liu et al., based on the perspective of institutional mechanisms, emphasized that regional integration is the process of eliminating obstacles such as institutions and policies between countries or regions and achieving full market competition [34]. At the same time, some scholars have further applied the concept of regional integration to aspects such as social governance integration [35,36,37], market integration [38], and industrial integration [39]. Based on ecological integration, Xi et al. emphasized that ecological integration is an important component of regional integration, and higher-quality development of regional integration cannot be achieved without ecological cooperation [40]. In addition, some scholars integrate exploration from different dimensions and view regional integration as a comprehensive integration of space, industry, and market composition [41,42].

Second, regarding the development impacts of regional integration, it is interesting to note that it corresponds to the concept of regional integration. Scholars initially focused more on the impact of economic development, but as research deepened, it gradually expanded to include aspects such as enterprise development, environmental protection, and the impact of urban quality development. Some scholars pointed out that the implementation of economic integration by the European Union has to some extent reduced the average level of inequality among member states [43]. Crescenzi et al. also acknowledged the positive effect of regional integration on narrowing regional gaps [44]. Muthoga et al., based on the theory of region and development, adopted the method of moments and found that integration does indeed have a significant promoting effect on regional economic development [45]. Zhang et al. and Yu et al. believe that regional integration can unleash potential market demand, effectively integrate the market, improve market integration, and thereby enhance regional labor productivity and promote economic development [46,47]. Brodzicki also pointed out that in the process of continuous regional integration, the per capita GDP of the region has increased [48]. In addition, the economic impacts of regional integration development can help the government adjust the prices of enterprise emission rights [49,50,51], force polluting enterprises to upgrade production technology [52], reduce cross-regional emissions of pollution [53,54], and improve the regional ecological environment [55,56]. Huang et al.’s research pointed out that regional integration not only improves economic growth efficiency, but also promotes high-quality urban development [57]. In addition, some academics have also concentrated on the following effects of regional integration: enterprise development [58], industrial structure upgrading [59], innovation level [60], urban land use efficiency [1], regional planning [61], etc.

Third, regarding methods for measuring the degree of regional integration, Parsley et al. first proposed a measurement method that measures the level of economic integration based on the variance of goods relative to retail prices in two regions using the commodity price index [62]. Engel et al. measured the degree of economic integration between the two regions based on their transaction volume and labor mobility [63]. Poncet used the trade flow method to measure the level of regional integration in China based on regional trade data [64]. Qian used the gap between regional actual output and theoretical output to measure the integration level of the Yangtze River Delta from 1978 to 2008. The study found that the development center of the Yangtze River Delta is Shanghai, and markets and institutions are indispensable factors in the integration process [65]. As regional integration research intensifies, regional integration not only consists of economic integration, but also in the integration of all fields. Therefore, scholars also need to build a comprehensive system of measurement. For example, Estrada measured the degree of regional integration by selecting relevant indicators from the economic, social, political, and technological aspects [66]. Sotirov et al. selected 26 indicators from six major categories of finance, industry, infrastructure, trade and investment, urban–rural development, and population mobility to measure the level of regional integration [67]. Zeng et al. selected four dimensional indicators for measuring the degree of regional integration in the Yangtze River Delta, including technological innovation, ecological environment, communication services, and economic development [68]. Similarly, Gu et al. and Liu et al. also constructed a comprehensive indicator system for gauging the level of regional integration [69,70].

Fourth, regarding the development path of regional integration, it is precisely because regional integration plays a significant role in enhancing regional economic efficiency, optimizing regional urban structure, and enhancing regional competitiveness, that many academics have been interested in the strategies and routes for establishing regional integration. Research has found that the “new regionalism” that emerged in the late 1990s is closely related to the study of the development path of regional integration, advocating that the way to coordinate different entities within the region is through governance rather than establishing formal regional governments [71]. On this basis, current research focuses more on regional planning [72], cooperative organizations [73], cooperation agreements [74], administrative divisions, etc. Sullivan et al. [75] also specifically pointed out that the resolution of cross-domain problems requires attention to important political, financial, and operational factors, and the establishment of cooperation mechanisms for networks, partners, and contracts. In addition, research on promoting regional integration paths in industries, environmental protection, and infrastructure has also received attention from some scholars. For example, infrastructure is considered the foundation for achieving regional integration and must be managed in a coordinated manner to form an integrated comprehensive transportation network [76], thereby providing support for regional cooperation.

Fifth, regarding policy research on regional integration, foreign research on policies mostly focuses on EU cohesion policies, and many scholars believe that EU cohesion policies can increase the per capita GDP of economically underdeveloped countries and narrow regional development gaps [77]. However, some scholars pointed out that the effectiveness of implementing EU cohesion policies varies in different regions. For example, Becker believed that EU cohesion policies can continuously eliminate economic disparities between different regions and enhance the level of EU integration [78]. However, some scholars believe that the EU cohesion policy is just a redistribution role, and its effect on narrowing the gap between countries and regions and enhancing overall economic development is weak [79]. However, overall, foreign research on policies also tends to focus on policy effects, and the same is true in China when focusing on the Yangtze River Delta. The integration of the Yangtze River Delta is a regional development case with Chinese characteristics that has not been researched abroad. There is a small amount of research on the integration policies of the Yangtze River Delta region from a quantitative policy perspective in China. For example, Zhou et al. analyzed the differences in the use of air pollution control policy tools in the Yangtze River Delta region from 2001 to 2018 from the perspective of policy tool changes. They suggested increasing the use of economic and information policy tools, improving policy coordination, and solving the fragmentation dilemma of air pollution control [80]. Zhao et al. revealed the development context of environmental governance policies in the Yangtze River Delta, found the transformation of policies from decentralization to centralization, and proposed a more precise positioning for future environmental policies [81]. Ma analyzed the integration policy texts of the Yangtze River Delta region from 2003 to 2018 and found that the current policy coverage in the Yangtze River Delta is relatively small, which is not conducive to further promoting integration [82].

Through the above literature review, existing research has focused on the connotation, implementation effects, integration level measurement, development paths, and other aspects of regional integration, covering important topics in regional integration research. Although these studies provide a research foundation and have certain reference value, there are still shortcomings, mainly a lack of systematic research on regional integration policy texts. Especially in the Yangtze River Delta, which is the subject of this study, although there are a few studies that analyze it from a quantitative perspective of policy texts, they only organize policy texts in a certain field and cannot display the overall development of integrated policies in the Yangtze River Delta. At the same time, the Yangtze River Delta’s integration is not restricted to only one type of integration, but rather a balanced integration in the economic, political, and social fields. Additionally, based on knowledge of the Yangtze River Delta’s process, it is discovered that every advancement in integration receives government policy support, demonstrating the close connection between policies and the realization of regional integration. Therefore, based on the importance of policy status and the shortcomings of current research, this article takes policy texts as the starting point and selects policies related to promoting regional integration in the Yangtze River Delta released from 2003 to 2022 as the research object. Using policy texts and social network methods, we quantitatively analyze the external characteristics and evolution laws of integration policies. Not only does this offer experience and a point of reference for the integrated development of other regions, but it also explores the problems and reasons of the Yangtze River Delta integration policy. Based on the actual development, corresponding adjustment suggestions are proposed to offer reference and guidance for the enhancement of existing policies and the formulation of future policies, ultimately enabling the rapid and stable realization of a high-quality development of regional integration in the Yangtze River Delta.

3. Policy Text Selection and Research Methods

3.1. Data Source and Text Selection

Policy texts include policy documents such as notices and opinions, laws and regulations, and plans issued by national or regional authorities at all levels, as well as official documents such as minutes, consensus, or suggestions formed by policy makers during the policy-making process [83]. The policy text actually carries the content of policy information, and by analyzing the policy text, it can truly reflect government behavior [84].

The selection of policy texts is an important part of text analysis, which requires strict adherence to the principles of authority, relevance, openness, and uniqueness to achieve the comprehensiveness and representativeness of policies. Authority means that policy texts must be formulated and published by government administrative agencies at the national or local level; relevance refers to the policy content that must be closely related to or capable of promoting the Yangtze River Delta’s integration; publicity refers to the fact that policy texts must be publicly disclosed and distributed to the public; and uniqueness means that duplicate texts must be eliminated to ensure that each policy text has only one copy.

In order to conduct a more comprehensive search for policies related to the Yangtze River Delta’s integration, we not only collected text data from the official websites of the People’s Government of China, the official websites of The State Council of China, etc., but also visited the websites of the people’s governments of Jiangsu, Zhejiang, Anhui, and Shanghai in the Yangtze River Delta region. Additionally, the government regulations, normative documents, and co-signed documents published by China’s “Peking University Magic Weapon” policy database and White Deer database and other websites were collected. The time range for selecting policy texts was from 2003 to 2022 (December 31). This is because 2003 is known as the “first year of the Yangtze River Delta”. After the release of the “Regulations of the Yangtze River Delta Urban Economic Coordination Committee”, cities in the Yangtze River Delta region were to hold regular meetings using the Urban Economic Coordination Committee as a platform to reduce fragmentation and achieve scale and concretization of regional cooperation.

In the process of collecting policy texts, the following steps were taken in this study: first, the keywords “Yangtze River Delta region” and “regional integration” were used to search official websites of governments at all levels and collect relevant policy documents. At the same time, to ensure the comprehensiveness of policy texts, relevant policy databases were also searched and local policy texts were collected. Second, in order to ensure the relevance of the policy text, the policy texts were organized and carefully read, and the policy texts on regional integration and cooperation formulated by the central government or the provincial and municipal levels of the three provinces and one city in the Yangtze River Delta as well as various prefecture-level cities were selected, including documents such as agreements, schemes, opinions, memorandums, projects, plans, and notifications. Policy texts that only mention “regional integration” but do not actually have substantive or relevant content were deleted, and meaningless texts such as letters, approvals, requests for instructions, key points, and lists were also removed. Third, it was necessary to ensure the uniqueness of policy texts, delete duplicate texts, and eliminate policy documents related to the Yangtze River Delta’s integration forwarded by various national ministries and local governments. Fourth, we removed policy texts that have lost their legal effect.

In the initial stage of policy text collection, a total of 939 policies were obtained in this study. Based on the criteria for selecting policy texts mentioned above, the collected policy documents were carefully screened, resulting in a total of 803 valid policy texts regarding the Yangtze River Delta’s integration.

3.2. Research Methods

In order to deeply analyze the policy texts dealing with the Yangtze River Delta regional integration promotion, the research methods used mainly included policy text analysis and social network analysis. The content research method called policy text analysis combines qualitative and quantitative analysis, and it can objectively and accurately explain policy variability [85], reduce the subjectivity of policy qualitative analysis [86], and attract significant attention in the policy field. Therefore, by using software tools such as Nvivo 12 and Excel 2003, analysis can be carried out from five perspectives: the type of policy text, the number of policy texts, the situation of policy makers, the fields of policy concentration, and the use of policy tools. It is possible to understand the development trajectory of the Yangtze River Delta’s integration at a macro level, and explore the main characteristics and existing problems in the promotion process of the Yangtze River Delta’s integration. The social network method mainly uses Gephi software version 0.9.2 to analyze the collaboration of policy makers, presenting the cooperation between policy makers in order to provide a reference for policymakers to better create policies and achieve regional cooperation.

Among them, Nvivo qualitative analysis software is a coding tool developed by the QR company to mine material information [87]. Therefore, in order to examine the evolution of policy tools, we mainly relied on Nvivo to analyze the content of the 803 policy texts, and used the software’s query text search function and human reading assistance to encode Nvivo. The search and coding object was a certain year’s policy text. For the selection of policy tools, different scholars have different classification standards. We mainly drew on the classification of the scholar Zeng and divided policy tools into contractual economic tools, structural forcing tools, and interactive impact tools [88]. Contractual economic tools refer to government departments’ management of public affairs based on contracts and agreements, which have strong flexibility; the structural forcing tool refers to a top-down coercive tool based on authority, with a single subject of action as the main body; the interactive impact tool refers to a tool used by government departments to manage public affairs based on influence. Based on the Yangtze River Delta’s integration development, 803 policy texts were further refined into 13 policy sub-tools through a search. The specific policy tools, search keywords, and reference point examples can be seen in

Table 1. List of policy tools and coding examples for the Yangtze River Delta’s integration.

Policy Tool Categories	Sub-Tool Name	Keywords	Example of Reference Points
Contractual economic tools	Government procurement	Procure, contract	Improve procurement policies for innovative products. Enhance the purchasing power of innovative products.
	Tax incentives	Taxation, deduction, finance and taxation	High-tech enterprises transferred to the demonstration zone and settled in it will be subject to income tax at a rate of 15%; enterprises that transfer comprehensive resource utilization enjoy preferential policies for comprehensive resource utilization in terms of corporate income tax.
	Strategic measures	Encourage, incentives, rewards	Cities and counties that carry out comprehensive land consolidation, ecological engineering restoration, and land conservation will be rewarded for increasing construction land use plan indicators.
	Financial investment	Finance, support, investment	Cities and counties are promoting greater investment in science and technology throughout society. In the next five years, provincial finance will allocate around CNY 60 billion, and municipal and county finance will allocate around CNY 60 billion.
Structural forcing tools	Establishing public sector	Establishment, department, institution	Establish a coordination team and office. The Joint Training Plan Coordination Team is composed of Shanghai Municipal Education Commission and Jiangsu Provincial Department of Education to determine the relevant policies and measures of the project.
	Law	Laws, regulations	Formulate regulations on source water protection of drinking water in the demonstration area, establish a unified ecological red line management and control system.
	Goal Programming	Goal, planning, vision	Long term goals: by 2030, the Yangtze Delta region will play a more important role as a global resource distribution center with important international competitiveness and influence.
	Working system	System	Establish an international talent shortage inventory system and an immigration career inventory system, with a focus on attracting the most valuable talents in technology, investment, marketing, and innovation.
Interactive impact tools	Public welfare promotion	Propaganda, news, media	Establish benchmark enterprise “quality story” promotional columns in major media, open high-quality promotional trains dedicated to subways and public transportation, and release “quality month” public welfare advertisements.
	Public facility construction	Facility, base, center	Comprehensively promote the construction of infrastructure such as transportation, information, energy, and water conservancy, and enhance infrastructure connectivity.
	Corporate communication	Enterprise, undertaking, transfer	Strengthen inter-provincial industrial cooperation, promote regional industrial transfer and orderly two-way flow of production factors.
	Information support	Network, data information	Promote information-sharing mechanisms, report community correction object information in a timely manner, and promote the connectivity of the information management system.
	Intergovernmental communication	Communication, temporary employment, cooperation	Establish a joint meeting system for the tourism associations of three provinces and one city in the Yangtze River Delta, and hold a meeting every year

.

4. Results and Discussion

4.1. Policy Types: Mainly Based on “Agreement” Policies

Through a statistical analysis of 803 titles of policy texts on the Yangtze River Delta’s integration, it was found that the policy texts issued from 2003 to 2022 have 21 types of forms, including agreements, schemes, opinions, memorandums, projects, plans, notifications, and decisions, reflecting the diversity of promotion methods for the Yangtze River Delta’s integration, as seen in Figure 1.

From the statistical results of the above policy types, it can be seen that there are various forms of regional integration policies in the Yangtze River Delta region. Among them, the main form is the “agreement” policy, which is a policy characteristic of the Yangtze River Delta region. The main policy makers are specialized institutions and various provinces and cities in the region dedicated to the integration. The increase in this characteristic policy demonstrates the increased initiative, enthusiasm, and cooperation awareness of various provinces and cities in the region during the promotion of integration. The number of formal and specific “project” and “plan” policies is relatively small compared to agreements; however, through understanding the process of the Yangtze River Delta’s integration, this does not indicate a decrease in the Chinese government’s willingness to guide at the macro level. On the contrary, it indicates that the Chinese government does not have too many restrictions on the promotion of the Yangtze River Delta’s integration, giving the region more autonomy, making it more flexible in policy formulation and more conducive to inter-regional cooperation. In addition, policies such as agreements, schemes, projects, plans, opinions, and notifications are more formal than other policy types and can comprehensively use various policy tools in policy formulation. Therefore, their specific content mostly includes parts related to regional cooperation such as “cooperation objectives”, “cooperation content”, and “cooperation priorities”. In terms of quantity, there are 609 formal and specific policy texts, accounting for 75.84% of the total policy volume. These policies are also presented in various forms, not only indicating the maturity of Yangtze River Delta regional integration development, but also demonstrating the diversity and flexibility of policies.

4.2. Number of Policy Annual Releases: Closely following the Trajectory of National Policies, Showing a Trend of First Fluctuating and Then Stabilizing Growth

According to the policy release time, the statistics of the number of policies from 2003 to 2022 are depicted in Figure 2. Analyzing Figure 2, it is clear that the number of policies introduced from 2003 to 2017 showed a “W”-shaped wave shape, while from 2018 to 2022, they showed a sustained growth trend. Although the number of policies has fluctuated, the overall trend still showed significant growth. Especially from 2003 to 2017, a total of 219 policies were issued, while 586 policies were issued in the three years from 2018 to 2022, which is more than twice the number of policies issued in the 15 years before 2018, indicating that regional cooperation has achieved significant results in recent years.

Specifically, on the one hand, the wave pattern from 2003 to 2017 indicates that the number of policies during this period is characterized by fluctuations and instability. This indicates that the progress of cooperation during this period was slow, the depth of cooperation was insufficient, and the cooperation among various entities was not strong enough. The wave pattern reached its maximum in 2003, 2010, and 2016, which is closely related to the relevant policies issued and the promotion of the cooperation process. For example, 2003 has always been regarded as the “first year of the Yangtze River Delta”. In this year, Zhejiang signed cooperation agreements with Nanjing and Shanghai. Subsequently, a regular meeting mechanism was established between the main leaders of the three provinces and cities of Shanghai, Jiangsu, and Zhejiang, which opened up frequent exchanges and visits between high-level officials of the three provinces and cities. In the same year, the concept of “people from the Yangtze River Delta” was first mentioned, which strengthened the awareness of collaboration among the region’s many provinces and cities. Therefore, the number of policies introduced in that year was particularly large. In 2008, the Yangtze River Delta absorbed the Anhui Province. Under the direction of government policies, the three provinces and cities of Jiangsu, Zhejiang, and Shanghai also continuously issued corresponding policies to promote regional cooperation. Following the introduction of the 2010 cross-provincial regional plan, the “Yangtze River Delta Regional Plan”, the Yangtze River Delta’s integration was once again promoted. Therefore, Figure 2 shows the trend of stable growth in the number of policies from 2008 to 2010. The “Yangtze River Delta Urban Agglomeration Development Plan” was released in 2016, further expanding the Yangtze River Delta’s scope and increasing the number of integrated policies. On the other hand, the number of policies showed a steady upward tendency from 2018 to 2022 mainly due to the fact that the Yangtze River Delta’s integration development rose to China’s national strategy in 2018. With the support of national policies, the enthusiasm and initiative of various provinces and cities in the region have greatly increased, and regional cooperation has been deepened.

Therefore, through the analysis of the number of annual policy publications from 2003 to 2022, it is evident that the changes in the number of policies are consistent with the time trajectory of the country’s introduction of important policies. At the same time, the number of policies is divided by the rise of the Yangtze River Delta as a national strategy in 2018, before which the stability of the number of policies was insufficient, and regional cooperation relied too much on the central government’s policy leadership, leading to passive cooperation driven by the central government. Afterwards, various provinces and cities in the region responded to the central call and increasingly valued regional cooperation, dedicating preferential resources and policies to it, resulting in a consistent rise in the number of policies.

4.3. Policy Makers: Cross-Departmental, Cross-Level, and Cross-Administrative Multi-Department Cooperation Are the Main Methods, Supplemented by Individual Provinces and Cities under the Guidance of the Central Government

4.3.1. Analysis of Independent Policy Makers

In order to effectively analyze the characteristics of independent policy makers in the Yangtze River Delta’s integration, the policy texts from 2003 to 2022 were collated and statistically evaluated. The results are displayed in Figure 3.

We found that the number of policies independently issued by the central government, three provinces, and one city was 355, accounting for 44.21% of the total policy volume. Among them, Zhejiang Province had the highest number of documents issued, with 118. The other three provinces and cities had a lower level of initiative and enthusiasm in regional cooperation compared to Zhejiang Province, and their policy content was mostly the implementation of central policies, with a lower level of active participation in the Yangtze River Delta’s integration. In addition, we found that the departments involved in regional policy formulation in the three provinces and one city included various levels of government, environmental protection departments, medical insurance bureaus, economic and information technology commissions, courts, social information offices, transportation departments, and other departments, presenting a diversified feature of policy formulation entities, and to some extent expanding the field of integrated cooperation, effectively promoting the regional integration process.

At the central level, more than ten ministries and commissions, including the National Development and Reform Commission, the Ministry of Industry and Information Technology, the Ministry of Transport, the Ministry of Finance, the Ministry of Science and Technology, and the Health Commission, are responsible for issuing documents. At the same time, observing their policy types, it can be seen that most central policies were “planning” and “guidance opinions”, while provincial policies were “promotion opinions”, “action plans”, “implementation plans”, etc. This suggests that the central government directs planning for various provinces and cities from the level of the Yangtze River Delta area as a whole, and that each province and city formulates policies in accordance with the viewpoints of the central government and local circumstances. The central government plays a crucial guiding role in the integration project of the Yangtze River Delta. From this, it is evident that the policy makers promoting the Yangtze River Delta’s integration not only exhibit the characteristics of joint issuance of documents by multiple provinces and departments, supplemented by separate issuance of documents by various provincial and municipal government departments, but also demonstrate diverse participation characteristics of local government departments from top to bottom under the guidance of the central government.

4.3.2. Analysis of Joint Policy Makers

In order to accurately understand the joint decision makers of regional integration policies in the Yangtze River Delta, the analysis was mainly conducted from two aspects: internal joint decision makers within administrative regions and cross-regional joint decision makers in different administrative regions.

(1)

Joint policy makers within administrative regions: cross-level, cross-departmental, and multi-subject collaboration led by authoritative departments of the central government

The joint formulation of policies within administrative regions mainly involves analyzing cooperation within the central government and within various provinces. Through further organization, it was learned that the number of jointly formulated policies within the central government and Zhejiang Province was 10 and 20, respectively. The number of jointly formulated policies within Jiangsu Province was four, and the number of jointly formulated policies within Shanghai and Anhui Province was five and three, respectively. The specific policy formulation entities are seen in

Table 2. Internal joint publications between the central government and the Yangtze River Delta’s three provinces and one city.

Year	Policy Name	Joint Policy Makers
2003	Several Opinions on Actively Connecting with Shanghai and Actively Participating in Cooperation and Exchange in the Yangtze River Delta Region	Zhejiang Provincial Committee of the Communist Party of China and Zhejiang Provincial People’s Government
2010	Framework Agreement on Strengthening Strategic Cooperation between the Two Cities	Nantong Municipal People’s Government, Wuxi Municipal People’s Government
2012	Opinions on Further Promoting Regional Cooperation in Transportation in the Yangtze River Delta Region	Shanghai Municipal Bureau of Transportation and Port Management
2016	The 13th Five Year Plan for the Development of Comprehensive Transportation in Zhejiang Province	Zhejiang Provincial Development and Reform Commission and Zhejiang Provincial Ministry of Transport
2016	Innovation driven industrial transformation and upgrading plan for the Yangtze River Economic Belt	National Development and Reform Commission, Ministry of Science and Technology, Ministry of Industry and Information Technology
2017	Ecological Environment Protection Plan for the Yangtze River Economic Belt	Former Ministry of Environmental Protection, National Development and Reform Commission, and Ministry of Water Resources
2017	13th Five Year Plan for Railway Development	National Development and Reform, Ministry of Transport, National Railway Administration
2018	The People’s Government of Xuancheng City printed and distributed the “Yangtze River Delta Integrated High-Quality Development Xuancheng Action Plan”	CPC Xuancheng Municipal Committee and Xuancheng Municipal People’s Government
2019	Cooperation Framework Agreement for Co construction of Metropolitan Area under the Background of the Hangzhou Jiaxing Mayor Triangle Integration Strategy	Hangzhou Municipal People’s Government and Jiaxing Municipal People’s Government
2019	Suzhou Wuxi Changzhou Integrated Development Action Plan (2020-2025)	Suzhou government, Wuxi government, Changzhou government
2020	Implementation Plan for Constructing the Yangtze River Delta Ecological Green Integrated Development Demonstration Zone in Wujiang District	Wujiang District Committee and District People’s Government of Suzhou City
2020	Special Action Plan for Promoting the Integration of the Yangtze River Delta Market System in Zhejiang Province	Office of the Leading Group for Promoting the Integrated Development of the Yangtze River Delta in Zhejiang Province
2021	Strategic Framework Agreement for Jointly Building the International Innovation Center for Green Development in the Yangtze River Delta Integration Demonstration Zone	Jiangsu Provincial Department of Ecology and Environment, Suzhou Wujiang District Government
2021	Water Resources Planning for the Jiashan Area of the Yangtze River Delta Ecological Green Integration Development Demonstration Zone	Zhejiang Provincial Development and Reform Commission and Zhejiang Provincial Department of Water Resources
2022	Implementation Opinions on Accelerating the Open and Shared “One Network Office” and “One Finger Office” of Large Scientific Research Instruments	Eight departments including Zhejiang Provincial Department of Science and Technology and Zhejiang Provincial Development and Reform Commission
2022	Shanghai Industrial Carbon Peak Implementation Plan	Shanghai Economic and Information Technology Commission, Shanghai Development and Reform Commission, Shanghai Science and Technology Commission, and Shanghai Ecological Environment Bureau

below.

Table 2 lists the policies jointly formulated by the central government, three provinces, and one city to promote the Yangtze River Delta’s integration. Specifically, the cooperation between central authorities and administrative departments was mainly led by the National Development and Reform Commission, in collaboration with departments such as the Ministry of Transport and the Ministry of Ecology and Environment, to promote the integrated development of the Yangtze River Delta in the fields of economy, transportation, and environmental protection. Within the provincial scope of the three provinces and one city, the main administrative bodies are their internal administrative body, which are led by the people’s governments of each province and city, in conjunction with relevant departments such as the Provincial Development and Reform Commission and the Ministry of Transport to formulate policies. Alternatively, the main leaders of each provincial government are responsible for controlling and drawing government personnel from relevant departments to form a working group to promote the Yangtze River Delta’s integration, in order to achieve cross-departmental joint policy formulation. This is particularly evident in Zhejiang Province. Overall, the joint issuing entities within the administrative region have begun to exhibit a trend of multiple entities across levels and departments, and a cooperation network between different departments at the provincial level has been formed. However, it should be noted that the number of joint publications within some provinces and cities is still relatively small, which to some extent affects their internal integration construction, thereby hindering the realization of comprehensive integration inside and outside the Yangtze River Delta.

(2)

Cross-regional joint policy makers from different administrative regions: a cross-domain multi-sectoral alliance led by the Executive Committee of the Yangtze River Delta Eco-Green Integrated Development Demonstration Zone

The policies jointly formulated across different administrative regions mainly include informal joint policies and formal joint policies. The informal joint policy refers to the regular or irregular meetings convened by government officials from various provinces and cities in the Yangtze River Delta region to discuss the Yangtze River Delta’s integration. After statistical analysis, we found that there were 19 instances of this special form of policy development carried out by the Yangtze River Delta Economic Coordination Committee, seven by 16 cities in the Yangtze River Delta, three by the Executive Committee of the Yangtze River Delta Integration Demonstration Zone, one by 18 cities in the Yangtze River Delta, one by the Yangtze River Delta Cooperation Office, one by the Joint Office for Cooperation and Development in the Yangtze River Delta, and one by the Joint Office for the Construction of the Yangtze River Delta Regional Innovation System. These forms of cooperation not only innovate the method of cross-regional cooperation in the Yangtze River Delta, but also promote the process of regional integration in the Yangtze River Delta.

The formal joint policy is an open cooperation document signed between the main leaders of various provinces and cities. According to the analysis of statistical results, the degree of regional joint decision-making was relatively high. The number of policies jointly formulated within the region was 448. Excluding intra-provincial and informal cross-regional collaborations, the number of formal cross-regional cooperation policies was 373, accounting for approximately 46.45% of the total policy volume. This indicates that the intensity of cross-administrative cooperation is greater than that of intra-administrative cooperation, and the various regions in the Yangtze River Delta have been managed in a subordinate manner towards collaborative cooperation. In fact, the joint formulation of policies by multiple entities can effectively solve the game problem of urban agglomeration development [89].

Due to the excessive number of policies, in order to better present the collaboration between formal cross-domain cooperation entities, social network analysis methods and Gephi software were used to analyze the decision makers of formal joint policies and create a cooperation network graph, as shown in Figure 4. In the cooperative network graph, “nodes” represent policy makers in cross-domain cooperation, and the cooperation relationship between entities is represented by line segments between nodes. The size of nodes and the thickness of line segments represent the number of policies jointly formulated by policy makers in cross-domain cooperation and the degree of cooperation.

Overall, the makers of cross-regional joint policies exhibit a characteristic of multi-departmental cooperation. From Figure 4, it can be understood that cross-domain cooperation is mainly focused on departments with consistent work content, which not only indicates the professionalism of integrated construction, but also has the characteristics of diverse entities. Among the 373 cooperation policies, more than 50 departments are involved, including the Science and Technology Department, Education Department, Human Resources and Social Security Department, Economic and Information Technology Department, Ecological Environment Department, Forestry Bureau, Port and Waterway Administration Bureau, etc., of three provinces and one city. On the one hand, this indicates that these departments have a high willingness to cooperate between provinces. On the other hand, the diversification of the main body indicates that local governments at all levels in the Yangtze River Delta are exploring and extending the scope of cooperation to achieve integration in more fields, which has a beneficial impact on advancing the integration process. However, it should also be noted that the line segments and nodes between certain cross-domain entities are relatively thin, and the cooperation intensity between entities is not high. The cooperation relationship still needs to be further strengthened.

Specifically, a multi-departmental and cross-regional cooperation centered on environmental protection has been formed. The administrative level of key cooperation departments between the central government, provinces, and cities is relatively high, providing guidance for regional cooperation. From Figure 4, it can be seen that the Executive Committee of the Yangtze River Delta Ecological and Green Integrated Development Demonstration Zone has the largest number of nodes, with the highest number of policies formulated. It is the center of many line segments, connecting the people’s governments, medical insurance bureaus, health commissions, municipal supervision bureaus, courts, and ecological environment departments (bureaus) of various provinces and cities. It is the core node of the entire cooperation network. This feature is related to the Chinese government’s emphasis on environmental protection in recent years and the construction of the Yangtze River Delta’s ecological integration. From the perspective of nodes and node line segments, policy formulation at the central level has formed a network structure centered around the Development and Reform Commission, the Ministry of Transport, and the Ministry of Environmental Protection. They have extensive connections with the people’s governments and ecological and environmental departments of three provinces and one city, while they have few connections with other government departments. This also indicates that the central government is paying increasing attention to ecological and environmental issues in the Yangtze River Delta region. Cross-regional cooperation among local policy makers is concentrated among the people’s governments, science and technology departments (committees), education departments (bureaus), economic and information technology departments (committees), ecological environment departments, transportation departments, quality supervision bureaus, public security departments (bureaus), and social information offices of three provinces and one city, with the highest cooperation density among these areas.

In summary, through the analysis of the cooperation network graph, it can be seen that all levels of departments within the administrative region of the Yangtze River Delta attach great importance to the “cross-border” issue of regional integration, and the cooperation between various entities has been strengthened. A cross-level, cross-departmental, and multi-agent cooperation network led by authoritative departments within the government has been formed. The cross-regional cooperation among different administrative regions in the Yangtze River Delta presents a cross-regional and multi-departmental cooperation led by the Executive Committee of the Ecological Green Integration Development Demonstration Zone, indicating the important position of environmental protection and the diverse characteristics of the main body in the integration construction. At the same time, the administrative level of key cooperation departments between the central government, provinces, and cities is relatively high, which to some extent guides and promotes the regional cooperation process. At this point, the degree of joint decision-making in the Yangtze River Delta region is relatively high, and various regions in the Yangtze River Delta have moved towards collaborative management. However, it is worth noting that in the graph of cooperation networks, nodes such as education, environmental protection, economy, and technology are relatively large, and the connecting line segments are thick, indicating that regional cooperation is generally concentrated in these areas, resulting in relatively few policies and resources obtained by other departments and fields, which can easily dampen the enthusiasm of other entities for cooperation and hinder the comprehensive development of integration. To this end, while maintaining the existing cooperation network, balanced allocation of policy resources in various fields should be carried out to enhance the enthusiasm of participants and ultimately promote better, faster, and higher-quality regional integration.

4.4. Policy Fields: The Scope of Cooperation Is Constantly Expanding, and the Integration Coverage Rate Is Increasing

From the collected data, it is evident that the fields covered by the Yangtze River Delta regional integration policy are constantly changing and expanding every year. For example, the initial focus on economic policies changed to the fields of infrastructure and technology, and in recent years to the promotion of environmental protection, healthcare, intellectual property, talent development, and other fields; this indicates that the Yangtze River Delta region is continuously expanding the scope of integration and striving to achieve full field integration. Specifically, as seen in Figure 5 below, the Yangtze River Delta integration policy covers 27 fields, including the comprehensive field, environmental protection, infrastructure, technological innovation, economy, law, education, sports, health care, and information. The largest amount of policies are in the comprehensive field, which mainly provides advice and guidance to the Yangtze River Delta’s integration in various aspects, including transportation, technology, environmental protection, etc. The second is the field of environmental protection and infrastructure. “Clear waters and green mountains” has reflected the importance of the ecological environment for human survival and development, and infrastructure is the cornerstone of integration, so they are two important items following comprehensive policies. The policies in the fields of technological innovation and economy have always been two important themes for the Yangtze River Delta’s development. At the same time, the comparison of economic and environmental policies not only indicates that the Yangtze River Delta is increasingly emphasizing the protection of the ecological environment, but also reflects the balance between economic development and environmental protection in the Yangtze River Delta. Finally, the emergence of policies in specialized fields such as law, education, credit, and logistics precisely demonstrates the diversification and diversity of the Yangtze River Delta’s integration.

However, further research has found that Jiangsu, Zhejiang, Anhui, and Shanghai place varying degrees of emphasis on policy fields, as shown in Figure 6. From the data in the figure, it is obvious that the number of policy releases in various fields varies among the three provinces and one city; however, except for Anhui, the other three provinces and cities attach the most importance to the field of comprehensive affairs, with a much higher number of policies than other fields. In addition to this field, specifically, Jiangsu attaches great importance to environmental protection, infrastructure, and scientific and technological innovation; Zhejiang pays more attention to environmental protection, law and government affairs, medical affairs and health care, and social security; and Shanghai focuses on the fields of tourism, finance, technological innovation, education, culture and sports. The industrial economy in Anhui is most prominent, followed by the comprehensive field, environmental protection, and tourism. The above results are in line with the actual social development degree of each province and city. Anhui is relatively weak, so it pays more attention to economic development, while the other three provinces and cities have a higher economic level, so they pay more attention to comprehensive development. In fact, this also implies that regional integration needs to be coordinated according to the different needs of the development of various provinces and cities.

4.5. Use and Evolution of Policy Tools

4.5.1. Overall Analysis of Policy Tools

Based on the coding content in Table 1 above, Nvivo software 12 was used to analyze the content of each coding point, resulting in the statistical results of the use of various policy tools and sub-tools, as seen in

Table 3. Statistics on the use of policy tools and reference points for the Yangtze River Delta’s integration.

Policy Tool Categories	Sub-Tool Name	Number of Policy Text Sources	Number of Reference Points	Percentage (%)	Total (%)
Contractual economic tools	Government procurement	42	52	0.66	11.71
	Tax incentives	94	153	1.96
	Strategic measures	170	439	5.62
	Financial investment	166	270	3.46
Structural forcing tools	Establishing public sector	84	97	1.24	29.45
	Law	187	318	4.07
	Goal Programming	350	883	11.32
	Working system	322	1000	12.82
Interactive impact tools	Public welfare promotion	175	231	2.96	58.84
	Public facility construction	285	747	9.58
	Corporate communication	305	849	10.88
	Information support	477	1332	17.07
	Intergovernmental communication	536	1432	18.35

. According to the statistical findings in the table, there is a significant difference in the amount of use between structural forcing tools, contractual economic tools, and interactive impact tools. Moreover, there is an imbalance in the use of policy tools and their internal sub-tools, with interactive impact tools having the highest usage, mainly relying on intergovernmental communication and information support; the use of structural forcing tools is relatively low, mainly relying on goal planning and work systems; and the usage of contractual economic tools is a bit too low, mainly relying on strategic measures. However, this also indicates that the process of the Yangtze River Delta’s integration is in the initial stage of development, with interactive impact tools dominating the use of policy tools, and that the awareness of collaborative cooperation among various regions is gradually increasing. However, institutionalization and market methods are not widely used, so in the process of promoting the Yangtze River Delta’s integration, while giving autonomy to each region, it is also essential to strengthen and attach importance to the guidance of structural forcing tools and the regulation of contractual economic tools.

4.5.2. Evolution of the Use of Policy Tools

In order to effectively analyze the usage of the three policy tools, we examined the number of times policy tools were used from 2003 to 2022. The specific results are shown in Figure 7. From the results, it can be seen that during the entire process of policy tool evolution, the use of early interactive impact tools and structural forcing tools was basically in a balanced state, while contractual economic tools were used, but the frequency of use was relatively low, and the gap between the three was not significant. However, since 2018, the gap between the three policy tools has been increasing, and interactive impact tools have always been in a leading position. The main reason for this pattern is that in the early stage of the Yangtze River Delta’s integration, it was still in the exploratory stage and could only adopt a balanced strategy of using three policy tools. Moreover, 2003 was the first year of regional cooperation in the Yangtze River Delta, and there was already a sense of cooperation among various regions. In the later stage, with the enhancement of coordination and cooperation awareness, the development of the Yangtze River Delta’s integration rose to the level of a national strategy and the Chinese government simplified and decentralized government power in various regions of the Yangtze River Delta. Moreover, these developments enhanced their autonomy and enthusiasm, resulting in the highest frequency of use of interactive impact tools, even far exceeding the other two policy tools.

4.5.3. Use of Policy Tools in Three Provinces and One City

From the above results, it is clear that there are differences in the use of the three policy tools. Therefore, in order to further analyze the characteristics of policy tool use, it is essential to analyze the usage of the sub-regions of the Yangtze River Delta region, namely the three provinces and one city. The specific statistical results are shown in Figure 8, Figure 9, Figure 10 and Figure 11, which are for Shanghai, Zhejiang, Anhui, and Jiangsu, respectively. From the statistical results, it is evident that, first, all three provinces and one city used the most interactive impact tools, and the usage was significantly higher than that of structural forcing tools and contractual economic tools after 2018. Second, the use of contractual economic tools in the three provinces and one city has been consistently low, and it did not show an upward trend until 2019. In particular, Anhui Province, due to its late accession to the Yangtze River Delta integration, did not start using contractual economic tools until 2006, which was the latest among the other three provinces and cities. This suggests that the three provinces and one city attach low importance to contractual economic tools. The use of contractual economic tools should thus be strengthened. Third, in terms of the stability of policy tool use, contractual economic tools were the most stable, followed by structural forcing tools, and interactive impact tools had the greatest volatility. Fourth, in terms of the number of policy tools used by each province and city, the difference in the number of three policy tools used by Zhejiang Province and Shanghai City was relatively small, indicating that the two provinces and cities have more experience, higher maturity, and stronger coordination in promoting regional integration. However, Jiangsu Province and Anhui Province still need to improve in these aspects. Fifth, the three provinces and one city had four peak periods in the use of three policy tools, namely 2003, 2006, 2010, and 2018. Interestingly, there are corresponding policy releases promoting regional integration at these peak periods, indicating that the frequency of policy tool use varies with policy releases.

5. Conclusions, Recommendations, and Limitations

5.1. Conclusions

Taking 803 policy texts on promoting regional integration in the Yangtze River Delta issued from 2003 to 2022 as the research object, the policy texts were analyzed from five different dimensions: policy types, policy quantity, policy makers, policy fields, and policy tools. The main characteristics of the policy texts on regional integration in the Yangtze River Delta were revealed, and the following research conclusions were drawn.

First, from the perspective of policy text types, the types of the Yangtze River Delta’s integration policies have diversity and flexibility, with agreement policies being the main focus and regional integration development being more mature. Specifically, there are 21 forms of policies for the integration of the Yangtze River Delta, which can be roughly divided into three categories based on quantity and form. The first category includes agreements, schemes, opinions, projects, memorandums, and notifications. These types of policies typically utilize various policy tools comprehensively, making the formulated policies more formal in form and specific in content, reflecting the authoritative guidance and proactive coordination characteristics of policies. The second type mainly includes declarations, plans, methods, decisions, measures, etc. These policies consist of task decomposition under the guidance of the first type of policies, with a larger emphasis on policy implementation norms. The third type of policy includes letters of intent and consensus, programs, guides, and other types, mainly serving as a supplement and innovation to regional cooperation forms. As a result, the Yangtze River Delta has formed a policy system that combines coordination, authority, standardization, and autonomy, and regional integration has a high maturity.

Second, the number of annual policy releases for the Yangtze River Delta’s integration follows the trajectory of national policies, with the growth first fluctuating and then stabilizing. Taking the rise of the Yangtze River Delta’s integration in 2018 as a national strategy as a boundary, the number of policies from 2003 to 2017 showed a “W”-shaped wave shape, with peaks in the number of policies in 2003, 2010, and 2016. Importantly, there were guiding policies and cooperation promotion events at this time point, indicating that regional cooperation during this period relied more on the central government’s policy leadership and to some extent belonged to passive cooperation driven by the central government. From 2018 to 2022, with the improvement of the strategic position of the Yangtze River Delta countries, various provinces and cities in the region seized the opportunity, increasingly valued regional integration, actively explored cooperation in various fields, and steadily increased the number of policies during this period.

Third, the policy makers of the Yangtze River Delta’s integration are mainly based on multi-department joint formulation across departments, levels and administrative regions, supplemented by individual provinces and cities under the guidance of the central government. Overall, they exhibit diversified characteristics. Specifically, on the one hand, for individual decision makers in regional integration policies, the single departments involved in the three provinces and one city include various levels of government, environmental protection departments, human resources and social security departments, social information offices, medical insurance bureaus, courts, economic information technology commissions, transportation departments, and other departments. The central level includes departments such as the Development and Reform Commission, the Ministry of Ecology and Environment, the Ministry of Transport, the Ministry of Finance, the Ministry of Science and Technology, and the Ministry of Health, presenting diversified characteristics of a single department. In addition, in the promotion of specific policies, the types of central policies are mostly “planning” and “guiding opinions”, while provinces and cities have “opinions”, “plans”, and “actions”, which are the implementation of central policies and reflect the important guiding role of the central government in regional integration construction. On the other hand, there are two types of joint decision makers in regional integration policies. One type is the cooperation between the central government and various provinces, forming a cross-level, cross-departmental, and multi-agent joint network led by authoritative departments within the government. Another type is cross-regional cooperation between the central government and provinces and cities, as well as between different provinces and cities. It presents a cross-regional and multi-departmental joint feature led by the Yangtze River Delta Ecological Green Integration Development Demonstration Zone. Overall, the degree of cross-regional joint decision-making in the Yangtze River Delta is relatively high, and various provinces and cities have shifted from territorial management to collaborative cooperation. However, it should be noted that in the cooperation network graph, there are significant differences in the size of each node and the thickness of each line segment, and the degree to which each entity receives policy resources and support also varies. To avoid dampening the enthusiasm of the entities, it is necessary to allocate policy resources in a balanced manner to ensure the full participation of each policy entity in regional cooperation.

Fourth, the scope of cooperation in the Yangtze River Delta region is becoming increasingly broad, involving 27 fields such as comprehensive integration, environmental protection, infrastructure, economy, technology, law, and education, and the coverage of integration is gradually increasing. At the same time, policy content in various fields mentions keywords such as regional collaboration, collaborative cooperation, regional linkage, and joint prevention and control, and the concept of regional collaborative cooperation is gradually strengthening. However, while expanding the field of integration, there is a problem of imbalanced development in many fields; for instance, the number of policies in the fields of police, civil affairs, logistics, and other fields is lower than 10, while the number of policies in the fields of comprehensive integration, environmental protection, infrastructure, economy, and technology exceeds 70. Such a large difference can easily promote the negativity and inertia of low-level sectors. At the same time, the number of policies issued by the Yangtze River Delta’s three provinces and one city varies in various fields, and there are also differences in the level of emphasis on development in each field. Therefore, there must be development contradictions between each province and city. To achieve comprehensive integration in the Yangtze River Delta region, it is essential to balance the development of various fields while paying attention to the differences in development needs and basic resources among provinces and cities.

Fifth, the policy tools for the Yangtze River Delta’s integration include structural forcing tools, contractual economic tools, and interactive impact tools. However, there is a serious imbalance in the overall and internal use of these three policy tools, with interactive impact tools being the most frequently used and consistently leading, with an internal bias towards intergovernmental communication and information support. The use of structural forcing tools is relatively low, and their usage has always been between the two other tools, relying internally on goal-planning and work systems. The use of contractual economic tools is too low and has always been the lowest among the three tools, relying mainly on strategic measures internally. In addition, based on the evolution of policy tools, there was not much difference in the use of the three policy tools from 2003 to 2017. Since 2018, although the use of various policy tools has increased, the gap in use has become increasingly large. This indicates that the synergy and integration between policy tools in the Yangtze River Delta are relatively low, and the stability and balance of policy use still need to be strengthened.

5.2. Policy Recommendations

Based on the above research conclusions, the following policy recommendations are proposed:

The first recommendation is to have a correct understanding of the differences in the development of various provinces and cities in the Yangtze River Delta, and prioritize the integration of ecology, technology, economy and other fields, while also promoting comprehensive integration in education, law, food safety, and other fields, in order to narrow the development gap in these fields, and mobilize and enhance the development enthusiasm of provinces and cities. Due to differences in geographical location, development level, and resources, the key fields of development within each province and city in the Yangtze River Delta are different. Based on the results in the policy field, Jiangsu, Zhejiang, and Shanghai pay more attention to the field of comprehensive affairs. This is because the three provinces and cities have explored the Yangtze River Delta’s integration earlier and have rich experience in various aspects. With the support of economic strength, they seek more balanced and stable development, so they attach relative importance to the field of comprehensive affairs. Due to its relatively late accession to integration and low-level of economic development, Anhui Province needs to seize opportunities to develop its economy and enhance its own strength in the development strategy of Yangtze River Delta integration. Therefore, Anhui Province focuses more on the industrial economy. However, precisely because of the differences in strength and development fields among the three provinces and one city, there are inevitably development contradictions among them, which will to some extent reduce the enthusiasm of individual provinces and cities. From the results of the number of policies made independently by the three provinces and one city, it can be seen that Anhui Province has the lowest number, which is not only related to its late accession to integration, but also a problem of participation enthusiasm. In the process of promoting integration, if certain fields are too concentrated, it is easy to cause imbalances in the cooperation relationships of other entities. Therefore, it is necessary to correctly understand the differences in development among different provinces and cities, coordinate the importance of field development, narrow the gap in field development, and improve the enthusiasm of each province and city to participate in the integrated construction, thus achieving full integration of internal coordination and external cooperation.

The second recommendation is to increase the use of contractual economic tools, maintain the trend of structural forcing tools, enhance the stability of interactive impact tools, and ensure the balance and effectiveness of policy tool use. The process of the Yangtze River Delta’s integration is in its early stages of development, so interactive impact tools are used most frequently and scientifically in the integration process, and the frequency of intergovernmental communication among sub-tools is also the highest. This indicates that the cooperation awareness of various provinces and cities in the Yangtze River Delta is constantly increasing in the integration development. However, from the evolution of policy tools, there is an imbalance in the use of the three policy tools, which must be adjusted. For interactive impact tools, their volatility is the highest, reflecting to some extent the instability of cooperation intentions among provinces and cities. Therefore, it is necessary to continuously enhance the concept and awareness of regional cooperation among provinces and cities, increase information disclosure efforts, explore new ways of information sharing, improve the degree of information sharing among regions, and enhance the stability of interactive impact tools. For structural forcing tools, the government is currently acting appropriately in streamlining administration and delegating power. Therefore, it is necessary to continue to maintain the current frequency of use or make appropriate adjustments with the increase in the use of the other two policy tools to ensure that the gap in the use of the three policy tools remains at a certain level. At the same time, the use of legal and regulatory tools within structural forcing tools should be appropriately increased to avoid obstacles to regional integration. Decision makers should increase the use of contractual economic tools, fully leverage the role of market leverage, strengthen subsidies to enterprises through tax incentives, and positively encourage enterprises to actively practice behaviors that are conducive to the integration of the Yangtze River Delta. At the same time, it is essential to increase financial investment, support and encourage governments and enterprises to increase their investment in integrated construction, and use market means to promote the specific implementation of integrated platforms and projects. In summary, continuous exploration and appropriate adjustments of the three policy tools can ensure the effectiveness of their use and effectively promote the process of the Yangtze River Delta’s integration.

5.3. Limitations and Prospects

This study provides a new perspective for the study of regional integration in the Yangtze River Delta and fills a research gap. However, there are still some limitations to this article. First, this study only selected the Yangtze River Delta region and did not involve regions with high levels of regional integration such as the Pearl River Delta and Beijing–Tianjin–Hebei. Therefore, the extrapolation of the conclusions of this study needs to be verified, and subsequent research can expand the scope of the case to promote and reference the research conclusions. Second, the research materials in this study are not comprehensive enough, as some policy texts are not publicly available or are in a state of pending development and improvement. In the future, the integration policy texts in the Yangtze River Delta region can be tracked and supplemented to enrich research materials. Finally, this study will inevitably be subject to subjective judgment by the authors, and will aim to remain neutral and comprehensively and objectively analyze the research case in the future.