Policy Reinvention in Diffusion: Evidence from Municipal Solid Waste Classi�cation Policy in China

While research on policy diffusion has attracted the attention of many scholars, little attention has been given to policy reinvention in diffusion. With the aim to explore the in�uencing factors and combination paths of policy reinvention in the Municipal Solid Waste Classi�cation Policy (MSWCP), this study constructs a theoretical framework concerning internal factors, intergovernmental relations and external in�uence, and carries out an empirical analysis on the MSWCP of 31 large and medium-sized cities in China using the Qualitative Comparative Analysis. Based on the empirical results, this study identi�es the different combination paths that induced local governments to reinvent policies and clari�es the various roles of �nancial resources, government attention, policy experience, peer competition, learning, and social demand in achieving policy reinvention, which is expected to provide new theoretical and practical enlightenment for policy reinvention research.


Introduction
Municipal solid waste classi cation (MSWC), regarded as one of the most important strategies to eliminate the "waste siege" and the dilemma of Municipal Solid Waste (MSW) management (Li et al., 2020), has received great attention in China.After the rst round of the policy pilot in 2000 [1], this action gained few successful outcomes (Xiao et al., 2017).Therefore, in March 2017, the National Development and Reform Commission and the Ministry of Housing and Urban-Rural Development jointly released The Implementation Plan of Municipal Solid Waste Classi cation System [2], marking the o cial introduction of the top-level design of MSWC and designating 46 key cities for MSWC.In January 2019, the Shanghai Municipal People's Congress approved the Regulation of Shanghai Municipal Solid Waste Management, indicating that for the rst time, local governments in China have raised the MSWC to the level of local regulations.In April 2019, the Ministry of Housing and Urban-Rural Development and other departments jointly issued a document requesting comprehensive waste classi cation work in cities at the prefecture-level and above across the country.
Due to the high levels of urbanization in developed countries, MSWC has been a concern among scholars for a long time (Starr & Nicolson, 2015).The management of MSW should be regarded as a public governance issue due to its increasing signi cance in the process of China's urbanization and the construction of a modern domestic waste management model (Xue & Fan, 2017).Azevedo et al. (2021) found that clear legal rules, regular public awareness campaigns, and waste charges are important for waste management.Two main pillars of the EU solid waste policy are the proximity principle and the self-su ciency principle (Reggiani & Silvestri, 2017).Donald C. Taylor (2010) concluded three types of policy incentives, including commandand-control regulations, social-psychological incentives, and economic incentives.As an objective re ection of the policy process, the policy text is also included in the important perspective of the MSWCP ( Existing research includes both single-link policy process research (such as policy formulation and implementation) and overall insights from the perspective of policy diffusion.However, a new perspective, policy reinvention, has been overlooked.Existing research mainly focuses on the determinants and mechanism of policy diffusion at the initial stage and pays little attention to the innovations during policy diffusion (Shipan & Volden, 2008;Walker, 2008;Yang, 2016).China's reforms experience a gradualist path of "crossing the river by feeling the stones", and its essence is a process of continuous policy innovation and a typical form of the "pilot-promotion" model (Zhu, 2010).The MSWCP is one of the products of the "pilot promotion" model, which has experienced a long evolution from eight pilot cities to 46 key cities and then to prefecture-level cities.To date, most cities in China have issued implementation plans or management measures or regulations aimed at promoting MSWCs.However, on a closer look, the MSWCP issued by various local governments is not completely convergent but has been adjusted on the basis of the documents at the central level and combined with the actual situation of the region.In other words, its policy diffusion process is accompanied by policy reinvention.Therefore, in the process of MSWCP diffusion, what factors contribute to the emergence of policy reinvention?Furthermore, the complexity of real society determines that the appearance of a certain result is often caused by a combination of factors.What are the combination paths for policy reinvention in MSWCP?
To answer the questions abovementioned, this study will explore policy reinvention in the MSWCP and use the organizational analysis framework to construct the in uencing factor model of policy reinvention in the MSWCP.Taking 31 large and medium-sized cities in China as research samples, this study uses qualitative comparative analysis (QCA) to explore the combined path of policy reinvention in the MSWCP.
Finally, based on the combination path, it summarizes the logic of Chinese local governments in promoting MSWCP innovation, which provides useful thinking for understanding policy reinvention in the Chinese context and then enriches the theoretical connotation of policy diffusion.From the perspective of responding to the actual demand, exploring the causal path of policy reinvention in MSWCP in China can help guide and promote the environmental policy innovation behavior of Chinese local governments, thus promoting the real implementation of China's environmental policy, and is expected to provide some experience for the vast number of developing countries. [

Literature review
The research on policy reinvention is a subset of the policy diffusion literature.As a process of communication and dissemination of certain policy innovations in the social system of time dimension, policy diffusion needs to rely on certain channels for its realization (Rogers et al., 2003).In most early research, it was assumed that the policy remained unchanged in the process of diffusion, so the policy adoption was coded by dichotomy (Scott et al., 1996).Although this assumption may be correct because some innovations are not suitable for reinvention in nature, for those that are bene cial to reinvention, checking this reinvention can add another important dimension to the research of innovation (Scott et al., 1996).Policy reinvention refers to the degree to which innovation is changed or modi ed by users in the process of adoption and implementation (Rogers et al., 2003)."Reinvention" is a process in which policy followers use the knowledge gained from other governments to modify the content of the new policy after its implementation (Clark, 1985;Guo & Ba, 2019;Mooney et al., 1995).
Research on the in uencing factors of policy diffusion and reinvention has attracted great attention.These factors were mainly the internal characteristics and external in uences of the government.Characteristics focused on the internal incentive factors of the system itself, mainly including the government's own social, economic, political and historical traditions(J.L. Walker, 1969;Berry & Berry, 1990).External in uences were related to policy diffusion mechanism, including horizontal and vertical diffusion mechanism (Shipan & Volden, 2006).Internal characteristics could greatly in uence policy reinvention, and even dominate the decision of policy revision (Carley et al., 2016).To be speci c, the internal characteristics could be the political system, such as the degree of democratization, ideological differences, interest groups, etc. (Tolbert et al., 2010;Glick & Hays, 1991), and economic considerations (Carley et al., 2016).Hays comprehensively took the in uence of social learning, ideology, and social context on reinvention into consideration (Hays, 1996).
Some scholars have pointed out that most of the previous theoretical achievements were made under the background of electoral democracy and developed economies (Boushey, 2010;Desmarais et al., 2017).
Therefore, some researchers have turned to the authoritarian background (such as China) to examine the phenomenon of policy diffusion.China has a unique Party-state system and hierarchical control and command chain (Ma, 2012), which all had a profound in uence on policy reinvention.On the one hand, the central government could maintain control over the provincial governments through the nancial and cadre assessment systems; On the other hand, the central government provided provincial governments with a high degree of administrative autonomy to promote economic growth (Lin & Xu, 2017)

Analytical framework
In line with previous studies, this study holds that the factors contributing to policy reinvention are not single but the combinations of many factors.Policy reinvention is a collective action within organizations.The New Institutionalism of organizational sociology holds that the organizational environment includes the technical environment and institutional environment, so organizations should follow both e ciency mechanisms and legitimacy mechanisms.The e ciency mechanism emphasizes that the adaptive behavior of the organization is based on the consideration of its own resource endowment, organizational operation e ciency and actual demand, while the legitimacy mechanism attributes the change in organizational behavior to the shaping of the environment (Powell, 1983).In addition, intergovernmental relations play an important role in the process of China's economic system reform.The political foundation of China's economic development achievements should be attributed to political decentralization, which has promoted economic vitality through innovation(Gabriella et al., 1995), an opposite view, however, is that the central authority under centralization is the real driving force to promote local pilot projects, thus promoting the wide adoption and innovation of policies (Cai & Treisman, 2006).Therefore, this paper divides the in uencing factors of policy reinvention into three categories: internal factors, intergovernmental relations and external in uences.

Internal factors
The internal factors include nancial resources, government attention and policy experience.Policy reinvention is a decision made by the resource endowment, such as public income, organizational resources and organizational capacity of adopters(J.Chen & Huang, 2021).Previous literatures have studied the impact of nancial resources, but paid little attention to the role of government attention as an organizational resource in policy reinvention.Organization could be regarded as an agenda setting system, and attention distribution can well explain why some events enter the agenda while others are ignored (Bouquet & Birkinshaw, 2008).The degree of attention referred to the concentration degree of speci c information, while the degree of government attention referred to the degree of attention given by the government to speci c information in complicated information, and then decided whether to take corresponding governance actions (Hogan & Eileen, 2001).Under multiple pressures, the administrative actions of local governments were highly related to their attention (Pang, 2019).Finally, the government's policy experience could also promote policy reinvention.As the investment cycle of MSWCP was long and the return is relatively lagging behind, compared with the explicit performance of investment and construction, it was unlikely to become the rst choice of local governments, and it faced great resistance in policy implementation (Chu & Wang, 2019).It was easier for local governments with previous policy experience to promote policy innovation (Zhang & Lin, 2022).

Intergovernmental relations
Compared with the research focused on adoption, intergovernmental relations were the core of policy reinvention literature (Carley et al., 2016).Intergovernmental relations could be divided into two categories: one was the vertical mechanism between local governments and the central government, and the other was the horizontal mechanism between governments at the same level.As China's municipal solid waste treatment has entered the era of compulsory classi cation, local governments might face the same compulsory pressure from higher authorities.Therefore, this article would not consider this factor.Economic competition and social learning were two main forces to promote horizontal policy diffusion (Boehmke & Witmer, 2004).Under the pattern of China's political centralization and scal decentralization, similar to market players, there was erce competition among governments, and they would take the initiative to gain the rst-Mover advantage or maintain the existing competitive advantage through some kind of innovation(Drezner, 2001).
Apart from competition, however, policy learning was another key mechanism of policy diffusion (Shipan & Volden, 2008).Policy reinvention originated from a social learning process, and the latecomers learned from the predecessors and modi ed the policies accordingly (Glick & Hays, 1991).Policy makers were often unable to grasp all the decision-making information, and policy learning could help policy makers avoid mistakes, emulate successes, and adapt innovations to local needs(Rice & Rogers, 1980).Where there were a lot of policies spreading, there were usually a lot of visitors (Ma, 2017).Through browsing the websites of local governments, we found that study tours between different local governments do exist.Therefore, we subdivided intergovernmental relations into two factors: peer competition and organizational learning.

External in uences
External in uences may lead to the expansion or inclusive growth of policies throughout the communication period, because later adopters were constantly developing on the basis of policies adopted earlier in the process (Clark, 1985).Policy was basically a response to societal needs, and we should take the social context into consideration (Hays, 1996).The policy reinvention adopted by the government was to deal with new social problems and try to nd new ideas and methods to realize the effective interaction between the government and society (Spender, 1994).Besides, the external driving effect of "promotion and appraisal tournament" on local government could even strengthen the in uence of social demand on policy reinvention of small and medium-sized enterprises.The construction of ecological civilization has been incorporated into the overall layout of the " ve in one" since the 18th National Congress of the Communist Party of China, and the "one-vote veto" rule of political promotion made it di cult for local governments to ignore environmental governance (Zeng & Zhu, 2021).In summary, we believed that social demand can exert an in uence on policy reinvention in the MSWCP.

Research method: crisp-set qualitative comparative analysis (csQCA)
Qualitative comparative analysis is a case-oriented research method that can be widely applied to exploratory and inductive research, as well as to con rmatory and deductive research (Eliason et al., 2009).It was created by Charles Ragin in 1987 for empirical studies with small samples.The outcome often occurs because of the combination of multiple conditions that give rise to the same result (Smith, 1990).The basic idea of this method is to explore how the combination of antecedents and conditions leads to observable changes or discontinuities in the interpreted results based on set theory and Boolean algebra (Ragin, 2008).The main interpretation of the results of QCA is based on two key concepts: consistency and coverage.Consistency is the extent to which similar causal con gurations give rise to the outcome, whereas coverage refers to the number of cases for which a given combination is valid (Smith, 1990).According to the difference in variable assignment, it is divided into clear set qualitative comparison analysis (csQCA), multivalue set qualitative comparison analysis (mvQCA) and fuzzy set qualitative comparison analysis (fsQCA).
The reasons for choosing csQCA are as follows: First and foremost, through theoretical analysis and literature review, policy reinvention should be the product of the comprehensive effect of various in uencing factors, and its causal relationship is rather complex, not purely linear.QCA is based on conditional combination analysis, which can gain insight into the complex causal relationship behind this phenomenon.Second, the number of cases to be selected in this research is not suitable for large-scale statistical analysis.QCA just breaks through the limitation of statistical analysis on large samples and can be applied to the analysis of small and medium samples (10-50 samples).Third, the judgment standard of the conditional variable and result variable assignment in this paper was a binary variable, which meets the requirements of csQCA for variable assignment.

Case selection
We preliminarily selected 35 large and medium-sized cities as case samples for the reinvention in the MSWCP.Considerations: First, based on the current situation of policy innovation and diffusion in MSWCP, MSWCP in China has spread to the municipal level.Moreover, compared with the policies at the provincial level, the policies at the municipal level are more detailed and easier to implement, and it is convenient to observe the degree of policy reinvention.The second one is based on the heterogeneity of cases.The 35 large and medium-sized cities have certain gaps in economic development level, resource endowment and administrative level, and their radiation scope is wide, covering different regions in eastern, central and western China.This makes the cases present different combinations of conditions, thus explaining the behavior choice of the local government's innovation diffusion.The third is the representativeness of the case.
In 2017, the central government identi ed 46 key cities for MSWC, requiring 46 key cities to explore practical experiences that can be replicated and popularized.The 35 large and medium-sized cities we selected were all key cities for MSWC.Fourth, this is based on the csQCA method.CsQCA requires the dependent variable to be binary (i.e., 0 or 1).Judging from the innovation degree in the sample cities, 35 large and medium-sized cities have heterogeneity in policy reinvention, which provides favorable conditions for using the QCA method.Last but not least, in terms of the number of samples and conditions, it is also suitable to take 35 cities as samples.However, the 35 large and medium-sized cities include 4 municipalities directly under the Central Government, which have a higher administrative level and better resource endowment.To avoid the bias of research, 4 municipalities directly under the Central Government were excluded, leaving 31 large and mediumsized cities [3] at last.

The outcome
The policy reinvention explored in this research refers to the policy innovation of a municipal government on the top-level document of MSWCP issued by the central level.This innovation is re ected not only in the content of policy text but also in concrete practice.To improve the accuracy of judgment, we adopt a mixed method to judge whether the adopters have recreated.
Firstly, the text content analysis method was applied.Policy text is the natural mark of government activities with traces to follow, including the formulation and implementation of policy (J.Chen & Huang, 2021).We collected the MSWCP in 31 large and medium-sized cities, and the selection follows the following two principles: (1) These policies are all o cial public documents, and the release time is after 2017.( 2) There is only one policy in each city, and the text selected needs to meet the two standards of the latest time and the most detailed content.Bennett once pointed out that the three elements of goal, content and tools constitute a complete policy (Bennett, 1991), which guides the text analysis in this part.This part of the work was independently completed by two authors, and the results were checked after the rst round and nally reached an agreement.Secondly, we must admit that the policy text cannot cover all recreation practices and that the real implementation should be considered.The central government has made o cial reports on cities with excellent policy practice to show its a rmation.Therefore, we used the news reports of government websites (mainly from the website of Ministry of Housing and Urban-Rural Development, PRC and some provincial websites) as secondary data resources to determine if reinvention was carried out.After that, we coded the city with policy reinvention as "1"; otherwise, it was "0".

Conditions
Condition 1: Financial resource (Finance).To promote the implementation of MSWCP, local governments need certain nancial resources to provide guarantees.This study used "per capita scal revenue" (the ratio of local general public budget revenue to the population) to measure the nancial resources of local governments.
The data come from the China Urban Statistical Yearbook and were collected from 2016 to 2019.The average of four years was used as the actual nancial resource capacity of the local government.If the value was higher than the average, the code was 1; otherwise, the code was 0. and word frequency (the judgment standard is that similarity is greater than 0.7 and word frequency is greater than 100), and the iteration was repeated continuously.Finally, 25 seed words, such as "environmental protection" and "waste classi cation", were determined.After importing the seed words into the local government's text database for word frequency statistics, the measurement of the local government's attention on MSWCP in each year was over.The nal data of each city were the average of four years from 2016 to 2019.If it was higher than the average of all sample cities, the code would be 1; otherwise, it would be 0.
Condition 3: Policy experience (experience).By browsing the website of the government on the o cial website, we determined the time when each city rst introduced the MSWCP, calculated the time difference in years (compared with 2021), and used this value as a measure of the policy experience of each city.
Condition 4: Peer competition (Competition).Referring to the practice of Ma (Ma, 2012), we used the percentage of other cities in the same province adopting MSWCP in 2020 to measure peer pressure.If it was higher than the average value of the sample cities, it was coded as 1; otherwise, it was 0.
Condition 5: Organizational learning (learning).This study rst used the news reports on the government's o cial website as a basis to judge whether the local government has studied from other cities.Second, we also used the policy text as the judgment basis.Some cities (such as Luoyang City and Zhanjiang City) explicitly mentioned in their policy text that they referred to the experience of some cities, so we used it as the symbol for learning.In terms of coding, the city with learning experience was coded as 1, and the city did not have such learning experience was coded as 0.
Condition 6: Social demand (Demand).MSW refers to solid waste generated in daily life or activities for providing services for daily life.Therefore, we used the total population of the region to measure the social needs of the region.The data were derived from China's Urban Statistics Yearbook, which took the average population from 2016 to 2019.Finally, the city above the average was coded as 1; otherwise, it was 0. Table 1 summarizes the measurement of the outcome and conditions in this study.

Necessity Conditions Analysis
Before the path combination analysis, single factor analysis is needed.In this study, the single factor analysis explored the in uence of a single conditional variable on the reinvention in the MSWCP.Generally, consistency higher than 0.9 is regarded as a necessary condition(C.Q. Schneider & Wagemann, 2012).Table 2 shows the results of the necessary condition analysis.The consistency of all the condition variables is less than 0.9, indicating that these six condition variables are not the necessary conditions leading to reinvention in the MSWCP and cannot explain the difference in the reinvention results alone.Therefore, it is necessary to further investigate its con guration.

Conditional Combination Analysis
Conditional combination analysis the effects of different combinations of conditional variables on the results when a single conditional variable does not constitute a necessary condition.In line with established research, we conducted a su ciency analysis by using a minimum case frequency benchmark ≥1 and raw consistency benchmark ≥0.8 (Fiss, 2011).In the conditional combination analysis, researchers will analyze the nonexistent state of the result as well as the existing state of the result.However, some scholars put forward a warning that the existence of results and the nonexistence of results are completely different concepts, events or phenomena in nature, which also means that the theoretical explanations and antecedents behind them will be different(C.Q. Schneider & Wagemann, 2012).Therefore, in this study, we only explored the combination of conditions that led to reinvention in the MSWCP and did not conduct counterfactual analysis.

gurations for the outcome of policy reinvention
There are three in QCA analysis: complex solution (without any logical remainder), intermediate solution (with only logical remainder that meets the theoretical direction expectation and empirical evidence) and parsimonious solution (with all logical remainder included without evaluating its reasonableness).Intermediate solution for its reasonability and moderation in complexity and presence of necessary conditions is considered to be the rst choice for interpretation in QCA research (Rihoux & Ragin, 2009; C. Schneider & Wagemann, 2013).Therefore, we carried out the analysis based on the intermediate solution (see table 4).Raw coverage in this table indicates the proportion of cases that can be explained for this reason combination in the total cases, and Unique coverage indicates the proportion of cases that can only be explained for this reason combination in the total cases.According to Table 3, there are nine combined paths that contribute to the innovation of domestic waste classi cation policy.Nine paths of policy reinvention explain approximately 76% of the results of policy reinvention.
We rst examined the similarities and differences in different paths.Path 3 is similar to Path 9, which reveals the path of local government policy reinvention under the situation of good nancial resources, certain policy experience and great government competition pressure.In other words, the existence of social demand can make up for the lack of government attention and learning to some extent and then promote policy reinvention.Path 8 re ects the important role of government attention in policy reinvention.When local governments have good nancial resources, abundant policy experience and extensive social demand, although there is no mutual investigation and learning between governments, they can also promote policy reinvention by increasing government attention resources.Path 1 further veri es the important role of government attention in policy reinvention.Without learning, the existence of government attention and social demand can promote policy reinvention, even regardless of the existence of government nancial resources and policy experience.Paths 4 and 6 highlight the impetus of intergovernmental learning and social demand for policy reinvention.When the local government learns more advanced policy experience, combined with social needs, the combination of good nancial resources and previous policy experience can make up for the unfavorable conditions of the absence of attention.In addition, even in the absence of nancial resources, government attention, experience and peer competition, as long as intergovernmental learning and social demand exist, policy reinvention can still happen.Paths 5 and 7 reveal the combination of the conditional variable of peer competition.When more cities in the same province adopt the MSWCP, to compete for scarce resources, local governments will form peer competition pressure for policy reinvention.This competitive pressure can contribute to policy reinvention through government attention or intergovernmental learning.
Finally, Path 2 shows the importance of government nancial resources.When the other ve conditional variables do not exist, government nancial resources may be an important factor for local government policy innovation.Note: "And", and "~" means the absence of the condition.

Further discussion
In this section, we conducted further discussion on the different paths that lead to policy reinvention in the MSWCP.Table 4 shows the conditional combination path drawn based on the parsimonious solution and intermediate solutions.The results reveal that the six conditional variables covered in this study are all the core factors that contribute to the reinvention in MSWCP, but these different core conditions need to work together with different conditional variables to contribute to the results.We summarized the paths of reinvention in the MSWCP among local governments in China, and they are "Internal resources and external pressure-driven", "Internal resources and intergovernmental relations -driven", "External pressure and intergovernmental relations driving", "Intergovernmental relations -driven" and "Comprehensive action -driven".
The rst pattern is "Internal resources and external pressure-driven" policy reinvention, which caused by the internal resources and external pressure of the government.Paths 1 and 8 provide good data support, and the cases include Qingdao, Zhengzhou, Nanning, Chengdu, Xi'an and Nanjing City.In path 1 and path 8, the four conditional variables, government nancial resources, government attention, policy experience and social needs, were core conditions leading to the reinvention in the MSWCP.Xi'an City is a typical case representative of Path 1.The government in Xi'an has always attached great importance to the city's environmental outlook."If the cigarette butts don't fall, Xi'an will be more beautiful" is an environmental improvement activity initiated by Xi'an for a long time.Furthermore, since Shanghai introduced local regulations on MSWC in 2019, Xi'an has also put related legislation on the policy agenda.All of these results indicate that government attention can promote policy reinvention.Secondly, the case of Nanjing City provides evidence for Path 8, which is a relatively ideal condition con guration with a high level of nancial resources, government attention, policy experience and social demand, moderate levels of peer competition and the absence of intergovernmental learning.As a provincial capital city, Nanjing has higher nancial resources than the average level.It can better guarantee the construction and maintenance of domestic waste sorting infrastructure through nancial resources and provide favorable policies and incentives to attract enterprises and citizens to consciously practice domestic waste sorting.Simultaneously, the performance of ecological environment management was included in the evaluation criterion for local governments, which has attracted the attention of the Nanjing Municipal Government.Additionally, as early as 2000, Nanjing was listed as the rst pilot city of MSWC by the central government, which helped it accumulate policy experience and gain insight into the di culties and shortcomings in the practice of MSWC.
Then is the "Internal resources and Intergovernmental relations -driven" pattern, referring to the policy reinvention promoted by the coexistence of internal government resources and intergovernmental relations.This is summarized based on Paths 3 and 5, and the cases include Hangzhou, Xiamen and Xining City.In Path 3. Xiamen City is a representative case of this con guration path.Xiamen enjoys preferential policies for special economic zones, and its government nancial resources are at a high level.With regard to the MSWCP process, Xiamen is also on the list of the rst round of pilot cities to try out the MSWCP and has accumulated some policy experience.Additionally, other cities in the province where Xiamen is located have successively implemented the MSWCP, resulting in greater peer competition pressure.All of the above promoted the emergence of Xiamen's policy reinvention.As for the Path 5, it shows the results of policy reinvention triggered by government attention and peer competition.Xining City, for example, is located in the western part of China, with a relatively low level of government nancial resources, lagging behind in implementing the MSWCP, and a relatively small population.However, driven by the attention of the government and the pressure of peer competition, Xining can still enhance its willingness to innovate the MSWCP.
The third one, "External pressure and intergovernmental relations -driven", refers to the path of policy reinvention driven by external pressure and intergovernmental relations.Shijiazhuang and Jinan City are case representatives of Path 6, which shows that when local government is faced with a shortage of nancial resources, government attention, policy experience and peer competition, its policy reinvention is mainly driven by intergovernmental study and social demand.The population of Shijiazhuang, for example, ranks at the forefront of the whole country, which re ects its strong social needs.Despite the disadvantages of nancial resources, government attention, policy experience and peer competition, MSWCP reinvention can be promoted through intergovernmental learning.Furthermore, it is consistent with the progress of MSWCP in China.China has experienced two rounds of MSWCP, trying to explore a more popularized domestic waste classi cation model through the experience summary of pilot cities and the mutual learning among governments.
In the fourth one, the pattern of "Intergovernmental relations-driven" explains the role of intergovernmental relationships in promoting policy innovation.This type is summarized based on Path 7, and Lanzhou City is the case representative.Competition and learning in intergovernmental relations constitute the driving force of local government policy innovation when local governments do not have the advantages of nancial resources, attention and policy experience, and the social demand is not obvious.Interestingly, compared with "external pressure and intergovernmental relations-driven", "intergovernmental relationship-driven" veri es the important role of peer competition in promoting policy reinvention.It assumes such a path of policy reinvention, that is, peer competition can replace social demand to some extent.As social demand is not obvious enough, the pressure of peer competition among governments can also stimulate the vitality of policy reinvention, thus winning a relative competitive advantage in a certain policy eld.
The nal one is so-called "Comprehensive action-driven", which reveals that the path of policy reinvention is caused by the coexistence of the interaction of internal government resources, external pressure and intergovernmental relations.It is supported by Paths 4 and 9, and the cases include Ningbo, Guangzhou, Nanjing and Hangzhou City.Financial resources, policy experience, peer competition, learning and social demand are regarded as the core conditions in Paths 4 and 9. Path 4 shows that policy reinvention bene ts from the advantages of nancial resources, policy experience, extensive social demand and intergovernmental learning.Taking Guangzhou city as an example, as one of the developed cities along the eastern coast and the provincial capital, its local government pays more attention to economic development, which may weaken the concern for the improvement of the domestic waste problem to some extent.However, thanks to its strong economic foundation, being included in the rst batch of pilot cities, and the policy demand generated by its huge population, it can still contribute to policy innovation through learning among governments.However, Path 9 provides an alternative choice.For local governments with the same advantages in nancial resources, policy experience and extensive social demand, the driving force that induces them to carry out policy reinvention is not only from intergovernmental learning but also driven by peer competition.Hangzhou City is a case representative of this path.With a high level of economic development, Hangzhou, located in the eastern coastal area of China, has a good nancial resource base.Also, as one of the rst pilot cities of MSWC in China, it has certain policy experience.Meanwhile, due to the population and the demand for urban transformation and development, its motivation for improving urban appearance is relatively high.What is different from Guangzhou, however, is that although Hangzhou municipal government has not learned experience from other cities (actually Hangzhou is often regarded as an example for other cities in practice), it is still able to promote policy reinvention under the pressure of erce peer competition.Notes: "•" indicates the occurrence of the precursor condition; "X" indicates the precursor condition does not appear; and a blank space indicates the precursor condition may or may not appear.

Robustness checks
used robustness test methods in QCA analysis include adjusting the calibration threshold, changing the consistency threshold, adding or removing cases, changing the frequency threshold, and adding other conditions (Zhang & Du, 2019).This study adopted the robustness test methods of changing the consistency threshold and deleting cases respectively.We rst increased the consistency threshold to 0.9, and found that the con guration result was still consistent with the previous one, indicating that it passed the robustness test.Then, we randomly deleted two cases (Shenyang and Dalian City), and found that the con guration results were basically the same as before, and the intermediate solution and complex explanation were exactly the same.Although the simple solution had one more path (~Attention*~Demand) than before, it did not affect the judgment of the original core conditions, which indicated that the research results of this study are relatively stable.

Conclusion
While the existing research is quite rich in the discussion of policy diffusion, the research on policy reinvention needs to be further deepened.The MSWCP in China has experienced the innovative diffusion process of "pilot-experience summary-repilot-promotion", which has revealed the relatively different local governance situation in China.The process of policy diffusion is not a single policy convergence but a policy reinvention in policy diffusion.To con rm this, this study started by exploring the combined path of policy reinvention in the MSWCP in China and constructed a theoretical model of policy innovation covering the three dimensions of internal factors, external in uences and intergovernmental relations.The main conclusions are as follows: a) Government nancial resources, government attention, policy experience, peer competition, learning, and social demand are the important in uencing factors promoting policy reinvention in the MSWCP.However, they do not constitute the necessary conditions but need to be combined with other factors to lead to policy reinvention.b) According to the differences in core conditions, nine combination paths that induce local governments to reinvent policies can be summarized as "Internal resources and external pressure-driven", "Internal resources and Intergovernmental relations -driven", "External pressure and intergovernmental relations driving", "Intergovernmental relations -driven" and "Comprehensive action -driven".c) When there is a good internal resource base (especially nancial resources, government attention and policy experience in this study), there are three ways to achieve local government policy reinvention: increasing extensive social demand, horizontal competition and learning mechanisms, and the nal is an ideal state with the combined function of all factors.d) Intergovernmental relations have strong explanatory power for policy diffusion in China since single-dimensional intergovernmental relations can even contribute to policy reinvention.In addition, its interaction with external social needs can also lead to policy reinvention.e) Only a good internal resource base of the government or strong social demand cannot realize policy reinvention, but it needs to further rely on the competition or learning mechanism of intergovernmental relations or realize the combination of internal resources and social demand.

Theoretical practical implications
terms of implications, this expands the traditional policy innovation and diffusion literature by adding policy reinvention as a dependent variable.Compared with those studies that only focused on policy adoption, we are more concerned about the follow-up of policy adoption, that is, whether the policy adopters have innovated on the basis of the original policy.Policy reinvention can show a more vivid process of how governments adapt and change when the diffusion of policy occurs.In terms of the administrative logic of local governments, it is di cult to escape the trap of "false adoption" from the perspective of dichotomy, while the study of policy reinvention may provide further explanation for local government behavior.Through this study, some instructive re ections have emerged.From the inside of the government, the difference in local nancial resources, the differentiation of government attention and the policy experience will affect the willingness of the local government to carry out policy reinvention.External in uences, such as social demand, are more like external pressures.China has a democratic election system different from that in the Western political system, and the administrative logic of local governments is often mistaken for "being responsible to the superior".However, in fact, external pressure from the public can be the driving force for local governments to carry out policy reinvention.Under the in uence of the Communist Party of China (CPC)'s ruling philosophy of "people-centered", the combination of "being responsible to the upper level" and "being responsible to the lower level" is the administrative logic that local governments uphold.
Intergovernmental relations provided a powerful explanation for deepening policy reinvention in China.Our research shows that even when local governments lack a good internal resource base and external pressure at the same time, intergovernmental relations can still drive policy reinvention behavior to a certain extent.Finally, our research on policy reinvention is expected to further enrich and expand the existing research on policy diffusion.
For practical implications, by taking MSWCP as an example, we summarize the development path of policy reinvention in policy diffusion, which can not only bring bene cial reference to local governments in China but also provide some inspiration to countries with similar governance situations.Local governments with good nancial resources seem to have won the opportunity for policy reinvention, but in fact, these alone are not enough.On the one hand, they should attention to adjust their attention resources in a timely manner and allocate their limited attention to the right areas.Meanwhile, they should make full use of the existing policy experience of the organization, re ect on it and carry out a more suitable and comprehensive one.On the other hand, competition and learning among different local governments are also important driving forces for policy reinvention, which can stimulate the enthusiasm of local governments for policy innovation and minimize the waste of policy resources caused by policy trial and error.For those local governments that did not have a good nancial resource base, assumptions should not be made that they cannot carry out policy innovation.In fact, by adjusting the government attention allocation, learning the advanced experience of other regions, and facing up to the social demand of the public in the jurisdiction, it can be possible to trigger the local government's policy reinvention.
Zheng & Chen, 2021; Wan & Wang, 2020).To explore the implementation of MSWCP, Zhou et al. (2019) took Shanghai as a case to introduce the current situation and existing problems of the implementation of the waste classi cation policy in Shanghai, while other scholars introduced the "Ambiguity-con ict model" (Chen et al., 2016), "Smith model" ( Li& Yang, 2020), perspective of attention( Li& Lu, 2020), and social mechanism perspective(Wang & Xu, 2020).Finally, a few studies introduced the perspective of policy diffusion into the research on MSWCP, analyzed the diffusion process of MSWCP in different levels of local governments in China, and summarized the in uencing factors of whether local governments adopted the MSWCP (Li & Gu, 2020; Lei & Wang, 2019; Tang & Tan, 2021).

Condition 2 :
Attention resource(Attention).We adopted the measurement referred to by Chen et al. and Huang et al. and took the frequency of relevant keywords in government work reports as a measure of government attention(Chen et al., 2018; Huang et al., 2022).In this study, we used the local government text database in WinGo[4]  as the data source of the government work report and applied its deep learning function of similar words and word frequency statistics.First, the Environmental Protection Law of the People's Republic of China, Law of the People's Republic of China on the Prevention and Control of Solid Waste Pollution and Regulations on Urban Scenery and Environmental Hygiene Management were used as the source of seed word screening.Second, the similar words of seed words were obtained based on the deep learning similar word module, and the seed words were further expanded by the statistical results of similarity

Table 1
Description of the outcome and conditions in the study

Table 2
Analysis of necessary conditions Notes: The symbol " " refers to the absence of the condition.

Table 4
Su cient leading to policy reinvention (based on solution and intermediate solution)