Effects of informal institutions on stakeholder and public participation in public infrastructure megaprojects: a case study of Shanghai

Public participation in public infrastructure megaprojects (PIMs) is ineffective, and research on the issues of informal institutions’ influence on stakeholders is limited. The present study answered how informal institutions influence the practices of public participation while conflicts occur among stakeholders. Two PIMs in China were used as case studies to investigate the effects of informal institutions. The paper suggests that the adversarial relationships among stakeholders can be reconciled by recognizing that informal institutions encompass the social responsibility of PIMs (SR-PIMs) and culture. Results also showed that effective public participation entails the fulfillment of SR-PIMs by responsible behaviors of stakeholders and the positive effect of cultural tension, enabling participatory awareness of stakeholders. This study improves understanding of how to mobilize stakeholders in practice with responsible behaviors to reach a consensus.


Introduction
In recent decades, many governments worldwide have launched many public infrastructure megaprojects (PIMs) to accelerate economic development and social welfare. PIMs are large-scale projects in which governments have invested more than USD 10 billion or have a considerable technical or functional complexity. PIMs also serve the public, involve multiple public and private stakeholders, take many years to develop and build, and affect tens of thousands of people (Flyvbjerg 2014;Wu, Jia, and Zhang 2019). Examples of PIMs include Heathrow Airport and California High-Speed Rail. To reduce stakeholder conflicts, promote democracy, and increase public acceptance (Sun, Zhu, and Chan 2016b;Liu et al. 2018), PIMs need to solicit comments from the public during the decision-making process (Brombal, Moriggi, and Marcomini 2017). Such interaction is called public participation and is usually involved in the procedures of environmental impact assessment (EIA).
The definition of public participation holds that stakeholders who are affected by the decisions of PIMs have a right to be involved in the decision-making process, and the public's contribution will influence the decisions (Arnstein 1969;Kung and Zhu 2022). However, in PIMs, ineffective public participation is always an issue. To guarantee effectiveness, institutions have been set up for public participation of PIMs, but the enforcement of formal institutions must also be incorporated into informal institutions (Li, Ng, and Skitmore 2016). Informal institutions are the informal constraints that organizations or people must follow in pursuit of their goals (North 1990;John and Sarianna 2008). Examples of informal institutions include norms, cultures, and social responsibility, and they exert latent effects on the practice of public participation. Thus, in PIMs, the effects of informal institutions on public participation should be investigated to achieve effectiveness.
The remainder of the article is structured as follows. Section 2 reviews the literature of informal institutions for public participation in PIMs. Section 3 describes the methodology in which a double-case study was designed by selecting two cases in Shanghai. Section 4 presents case studies to examine the fulfillment of the social responsibility of PIMs (SR-PIMs) and explain the effects of cultural tension. Section 5 discusses the effects of informal institutions. Section 6 concludes.

Literature review
As part of the "rules of the game," institutions are divided into informal and formal institutions (North 1990;Scott 2007). The latter involves a set of formal rules, such as laws, regulations, and policies, to constrain or stipulate the behaviors of people. Although related laws and regulations are already in place in China, effective public participation in PIMs remains difficult to achieve (Tang, Wong, and Milton 2008;Cicmil and O'Laocha 2016). Ineffective public participation fails to address the concerns of stakeholders effectively and even results in project failure by exacerbating stakeholder conflicts (Sun, Zhu, and Chan 2016b;Wu, Jia, and Zhang 2019). To achieve effectiveness, from the perspective of formal institutions, many scholars have investigated laws (Shan and Yai 2011), institutional arrangements (Wu, Jia, and Mackhaphonh 2019), appropriate participatory rules (Li, Ng, and Skitmore 2016), and implementation mechanisms (Xie et al. 2017). However, under certain circumstances, the distinguishing factor is informal institutions (Williamson 2000;Sauerwald and Peng 2013), which overwhelm formal institutions to influence effectiveness.
Informal institutions affect public participation by various informal rules that cultural differences and SR-PIMs take on in practice (Tang, Wong, and Milton 2008;Shan and Yai 2011;Sinclair and Diduck 2017). Zhou and Mi (2017) defined SR-PIMs as that which "involves the policies and practices of the stakeholders participated through the whole project life-cycle that reflects responsibilities for the well-being of the wider society." Wu, Jia, and Mackhaphonh (2019) found that pertinent institutional arrangements follow rules and that the fulfillment of SR-PIMs guides stakeholders to adopt positive behaviors to enable substantive public participation. In PIMs, high public concern results in the fulfillment of SR-PIMs (Lin et al. 2018), and SR-PIMs take on different issues of public participation in initialization phases (Zeng et al. 2015).
Formal institutions that do not fit their cultural settings lead to poor enforcement (Creighton 2004). Therefore, culture becomes a substitute for formal institutions and increases the significance of informal institutions (Helmke and Levitsky 2004;Sauerwald and Peng 2013). In China, the cultural and sociopolitical heritage and practices for implementing public participation are distinct (Liu et al. 2018). Compliance and standards of officialdom serve as the core elements of culture (Li, Ng, and Skitmore 2012;Li, Ng, and Skitmore 2013), in which Chinese people are seldom involved in the decision-making process (Plummer and Taylor 2004;Tang, Wong, and Milton 2008). In traditional Chinese culture, most people are used to being dependent on paternalistic governments that protect their welfare and make reasonable decisions on public affairs (Tang, Wong, and Milton 2008;Shan and Yai 2011;Chi, Xu, and Xue 2014). In the context of China, cultures may be barriers to effective public participation (Petts 2003;Kranz et al. 2007;Sun et al. 2016a). Therefore, studying how cultures influence public participation is necessary.
Certain studies have found that effective public participation is largely dependent on the awareness and behavior of stakeholders (Sagie and Aycan 2003;Whitton et al. 2017;Wu, Jia, and Mackhaphonh 2019). Here, informal institutions would take on effects, such as culture (Li, Ng, and Skitmore 2012;Liu et al. 2018;Dai et al. 2022) and social responsibility (Zeng et al. 2015;Wu, Jia, and Mackhaphonh 2019). Although previous studies have found that informal institutions would influence effectiveness, no in-depth study has focused on the effect mechanism of informal institutions on public participation, and the causal links between informal rules needs to be elaborated. Therefore, in PIMs, effective public participation requires an understanding of the effects of informal institutions. To narrow this gap, the present study investigated cultures and SR-PIMs and their causal links to reveal the effect mechanism of informal institutions.

Theoretical framework
When "how" or "why" questions are being raised, the case study method is the preferred research strategy (Eisenhardt and Graebner 2007;Yin 2009). A theory must be posed to explain the prevalence of a phenomenon and understand how the explanations could apply to other situations (Yin 2009). Compared with a single-case study, a multiple-case study has advantages in that the evidence is more compelling. The overall study is therefore regarded as being more robust. In this paper, a double-case study has been designed to follow the replication logic. The principles used in selecting the cases include differences in the type of PIMs and geographical positions, but the most important principle is the phenomenon that culture and social responsibility affect public participation.
In PIMs, effective public participation is influenced by informal institutions. Therefore, SR-PIMs and culture are crucial in practice. This paper investigates the causal links of SR-PIMs and culture on public participation and how to use them to help alleviate conflicts. Three key research questions were posed to discuss the issues of informal institutions in public participation in PIMs.
1. How do SR-PIMs influence the behaviors of stakeholders? 2. How does culture influence the awareness of stakeholders? 3. How do informal institutions help alleviate conflicts? Question (2) explains the awareness of stakeholders while question (1) answers how to turn this into responsible behaviors. Questions (1) and (2) are prerequisites for (3), that is, the causal links of awareness and behaviors is helpful to answer Question (3). Figure 1 shows the theoretical framework. SR-PIMs and culture are composed of informal institutions for public participation in PIMs. SR-PIMs are important for public participation (Zeng et al. 2015;Ma et al. 2017) and could be evaluated by the participatory behaviors of stakeholders (Wu, Jia, and Mackhaphonh 2019). The core elements of culture can generate cultural tensions that influence the participatory awareness of stakeholders (Boyle 1998;Shan and Yai 2011;Li, Ng, and Skitmore 2012).

Data collection and analysis
The Airport Extension Project (AEP) and Chest Hospital Extension Project (CHEP) were used as study cases, for the following reasons. (1) informal institutions have an effect in dealing with conflicts during the process of public participation. (2) In practice, social responsibility reconciled stakeholders' behaviors. (3) Shanghai regional culture generates a positive effect on the local community to influence decisions.
The paper created a database from the following sources. First, the author conducted semi-structured interviews with staff (as seen in the appendix [online supplementary material]) who served in the lead agencies of the two PIMs to investigate public participation regarding results, reasons, benefits, issues, and suggestions. Second, the author implemented complementary surveys via communication tools (i.e. QQ, WeChat) to investigate the effects of social responsibilities and the potential effect of cultures. Third, secondary data, such as Internet posts, EIA documents, and news reports, were used to reveal the behaviors and attitudes of stakeholders during the process of public participation. The objectives are to evaluate the fulfillment of SR-PIMs in the two PIMs and reveal the effects of cultural tension through inductive logic by processing the database as construct coding in Table 1.
Following the tactics of Yin (2009) to improve the credibility and validity of case study, this paper uses the principle of triangular verification that used multiple firstand secondhand data sources (Table 1). A time-point chain of evidence was then built ( Table 4). The double-case study was designed to collect the data of AEP and CHEP to achieve external validity and replication logic. Here, an evaluation indicator system was used to investigate the identical effects of SR-PIMs and cultures that existed in the two cases (Table 3).

Case studies 4.1. Public participation in AEP and CHEP
The AEP is located 30 km away from the downtown area of Shanghai (Figure 2), and its total collective investment is approximately USD 2.9 billion. The construction aims to renovate Terminal 1. With the AEP, the transport capacity will be expanded, and the air transport capacity of the region can be improved to promote socio-economic development. The Airport Construction Headquarters (ACH) is the lead agency formed to implement public participation and is the decision maker of the PIM. The key environmental  issues are noise and radiation. Both factors would affect the life and health of affected communities adjacent to the PIM. Figure 3 shows Residential Areas I and II. The CHEP is located in the center of Shanghai ( Figure 2) and has recorded stateowned investments worth USD 22 million. The goal of the extension project is to meet the urgent demands of patients and medical research and development in the area of thoracic diseases. The Shenkang Hospital Development Center (SHDC) is in charge of decision making for the project and is the lead agency to implement public participation. The construction plan is to build a new high-rise multi-functional medical building that will radically change the living environment of nearby communities and limit their solar access and block their view. Figure 4 shows Residential Areas III and IV. The construction stage will generate noise and vibrations, which could adversely affect communities' daily life and cause occasional traffic jams.
The existing Chinese laws or regulations of public participation in PIMs are as follows. The Environmental Protection Law of the People's Republic of China (PRC) was enacted in 1989 to protect the living environment and was revised in 2014 to strengthen public participation in the process of EIA. In 2002, the EIA Act of the PRC further stipulated that lead agencies must solicit public comments before compiling an EIA report and circulating the draft report. This law was further revised in 2016 with no changes in the guidelines for public participation. The Interim Measures for Public Participation in EIA was enacted in 2006 to guide public participation in EIA. The Ministry of Ecology and Environment has revised it (effective 2019) to guide lead agencies in effectively implementing public participation.
According to these laws and regulations, public participation of ACP and CHEP should seek public comments as much as possible to achieve the objectives of environmental protection and social stability. ACH and SHDC expected that effectively involving the public, obtaining their wide support and understanding, increases the success rate of PIMs (Creighton 2005;Wu, Jia, and Zhang 2019). Although pursuant to the laws and regulations, in these cases, public participation was still ineffective to meet the objectives of the two PIMs (Table 2), thereby causing conflicts among stakeholders and affecting the success of the PIMs.

Fulfillment of social responsibility in AEP and CHEP
According to the different claims of interest, including diverse accountability, professional backgrounds of various types of stakeholders (Mok, Shen, and Yang 2015; Table 2. Ineffectiveness in public participation of the two PIMs.

Project
Effects on the project AEP Environmental protection measures and compensation plans were not accepted by affected communities The affected communities kept protesting to the government and the superiors of ACH, affecting the schedule of the project and social stability The public was absent from the process of decision making CHEP The affected communities directly petitioned the leader of SHDC rather than engage in public participation The final design scheme showed partial impairments in the medical functions of Building 3 The public was absent from the process of decision making Anti-corruption Insufficient concern over social and regional influence Anti-corruption Insufficient concern over social and regional influence    Given the importance of public participation in the societal governance of SR-PIMs, an evaluation indicator system needs to be developed Ma et al. 2017). This system evaluates the social responsibility of the two PIMs in the aspects of public participation through the behaviors of stakeholders . SR-PIMs are categorized into the following four groups according to Zeng et al. (2015) and Lin et al. (2017): legal responsibility (LR), political responsibility (PR), ethical and environmental responsibility (EER), and economic responsibility (ER). On the basis of interviews and secondary data, the authors created Table 3, which demonstrates how social responsibility was being fulfilled by the stakeholders during public participation in the two PIMs.
LR: ACH and SHDC met the basic legal requirements to implement public participation and passed the government examination of the results of public participation. The government did not endeavor to promote public participation, information disclosure was incomplete and untimely, and the EIA report was the abridged version. The affected communities would adopt unofficial ways to defend their interests rather than engage in public participation. For instance, ACH received complaints or petitions from affected communities regarding the noise produced by the airport. No public comments were raised when they conducted public participation. The media only reported positive information about the AEP and CHEP, but neglected to report the adverse effects on the affected communities.
PR: Given the Chinese government's pressure on the anti-corruption of PIMs, no corruption was observed in the two PIMs. The government was insufficiently concerned about the adverse effects of PIMs on local communities, and such disregard caused protests by the affected communities. ACH collected 230 questionnaires from the affected communities and found that 71.7% were supportive, 20% were indifferent, and 8.3% opposed those who petitioned the government and the superiors of ACH. ACH consistently endeavored to maintain a favorable relationship with the local communities, although they sometimes experience protests. For the CHEP, more than 50 affected residents filed petitions to oppose the design scheme of CHEP. SHDC stated that the affected communities ought to elect representatives to express their opinions through the channel of public participation. After several rounds of negotiation, SHDC and affected communities reached a consensus with a major adjustment for the design scheme and compensation plan.
EER: SHDC and ACH conducted the EIA in 2008 and 2014, respectively, to reduce the project's adverse effect on society and the natural ecology. SHDC and ACH adopted green construction techniques and schemes following a green technical standard. The affected communities were concerned that the projects would affect their living environment and property value. SHDC implemented extra noise reduction measures during the construction stage and staggered working times to guarantee communities' life quality. ACH invested considerable resources to protect the natural ecology and entrusted third-party organizations to provide expertise. However, noise and radiation constantly affected the living environment of the affected communities who were constantly complaining to the superior of ACH (Noise of Airport 2017).
ER: In the initial stage, the governments censored the economic feasibility of the two PIMs, and the economic effect of the projects on stakeholders emerged as a concern. SHDC and ACH adopted environmental protection measurements and economic compensation to ensure the quality of the local living environment. Both also employed third-party professional organizations, providing expertise to control construction costs and schedules of PIMs. The media reported the economic benefits of the AEP to regional development. However, certain affected communities claimed that ACH should buy or compensate the real property or life of the community, which were seriously affected by the project. ACH refuted these claims as being groundless in the legal context. SHDC reached a consensus with the affected communities with regard to the compensation plan, which was sufficient to cover the loss of the affected communities caused by construction noise and traffic inconvenience.
The social responsibilities of the two PIMs were not fulfilled thoroughly such that public participation was ineffective to deal with the issues of stakeholders. The government and lead agencies focused on macro-level social responsibilities, including applying the law, promoting anti-corruption measures, maintaining social stability, guaranteeing environmental protection, and ensuring the economic benefits of the PIMs. The affected communities were concerned about their living environment and economic interests. Such concerns have become a formidable part of public participation in PIMs and the fulfillment of social responsibility. By contrast, the public did not fulfill their social responsibility well and were inactive in the decision-making process of the PIMs (Table 4). Therefore, the evaluation results of the social responsibility of the two PIMs are consistent with the self-evaluations of ACH and SHDC. These findings revealed that the results of public participation only met the basic legal requirements but failed to achieve the expected objectives.
In PIMs, the stakeholders were motivated by compulsory legal requirements or their private interests to participate in the decision-making process. ACH and SHDC implemented public participation given the compulsory legal requirements and administrative regulations, including the government's approval of the results of public participation. The affected communities were essentially positive when protecting their private interests, potentially contradicting public interests. The public was indifferently involved in the decision-making process in PIMs because they had no legal obligations and direct interest conflicts. On these bases, the participatory awareness of the stakeholders was inadequate to support effective public participation in the PIMs.
The majority of the public has minimal technical knowledge and a sense of social responsibility, increasing the challenges in public participation. Furthermore, the affected communities thought that ACH was being irresponsible about the adverse effects of the project on the living environment, and the compensation scheme or environmental protection measurements could not offset their losses. Similarly, SHDC needed to change the design scheme of the hospital project according to the requirements of the affected communities, although the change would affect the medical functions of Building 3 (Figure 4). The reason for these changes is that the affected communities lacked medical expertise to understand the rationale of the original design scheme. The conflicts between private and public interests and professional and unprofessional backgrounds are inevitable in the process of public participation in PIMs. They cannot be merely solved by formal rules.

Effects of cultural tension on stakeholders
In both PIMs, the participatory awareness of the stakeholders was insufficient to achieve effective public participation. In particular, the public was absent and minimally contributed to the decisions of PIMs. One reason for this deficiency is traditional Chinese culture, in which compliance and a top-down decision model minimize the willingness of stakeholders to engage in public participation. Compliance is the core element of feudal Confucian culture (Shan and Yai 2011;Li, Ng, and Skitmore 2012), which continues to exert a profound influence on Chinese people who are unwilling to be positively involved in the decision making of PIMs. The hierarchical structure of the Chinese government also generates a political-administrative culture (Sun, Zhu, and Chan 2016b), which is contradictory to the spirit of democratic deliberation of public participation. This structure also benefits a top-down decision model.
Culture naturally generates tension to force people to behave in extensive compliance with specific cognition and norms. This phenomenon is referred to as cultural tension (Yan 2008). Negative cultural tension would harm the participatory awareness of stakeholders, whereas positive cultural tension would increase the participatory awareness of stakeholders. The positive and negative dimensions of cultural tension are determined by the core elements of culture, that is, whether culture is favorable to the people involved in the decision-making process and is adaptive to an inclusive decision model. For AEP and CHEP, traditional Chinese culture emphasizes compliance and top-down decisions in cultural value orientation, under which cultural tension negatively affects public participation in PIMs in China. Cultural tension explains the weak participatory awareness and inactive participation of the public during public participation in the two PIMs.
Traditional Chinese culture is a dominant culture that has evolved into subcultures (Tang, Wong, and Milton 2008;Shan and Yai 2011), such as organizational and local cultures, to affect stakeholders' awareness toward public participation in PIMs (Table 5). Organizational culture exerts a negative effect on formal organizations that fail to fully implement public participation, even though new formal institutions have already raised the requirements (Warrick 2017). Traditional Chinese culture exerts a negative effect on citizens and informal organizations in which people are unwilling or unused to being involved in the decisions of PIMs. However, the affected communities in AEP and CHEP are active in defending their private interests in the decision making of PIMs. In this study, the Shanghai regional culture exerts a positive effect on affected communities' behaviors.
Laws require the sufficient solicitation of public comments when making decisions related to PIMs (Shepherd and Bowler 1997;Sun et al. 2016a). The discretion to do so lies in the lead agencies and governments, which still hold the final decision power in PIMs. Lead agencies and governments are under the dominance of the organizational culture, in which economic and technical concerns outweigh social ones when making the decisions of PIMs. Furthermore, in practice, the priorities of ACH and SHDC were to meet the basic legal requirements rather than mobilize the public and solicit their comments. The psychological expectation of lead agencies and governments is that public participation is a mere formality with little benefit to decision making and the construction of PIMs. The organizational-cultural tension caused the unwillingness of lead agencies of the two PIMs to fully implement public participation. An organizational culture that prioritizes economic development is prevalent in governments (Boyle 1998); such a culture focuses on the economic and technical aspects of PIMs and relevant performance appraisals (Souhu News 2013). Under a similar organizational culture, the final EIA reports of AEP and CHEP could still be approved by the governments, although they knew that public participation was still ineffective.
In AEP and CHEP, Shanghai regional culture overwhelmed traditional Chinese culture to exert positive effects on affected communities. The public was absent in the process of public participation because Chinese citizens scarcely engage in decision making on public affairs (Plummer and Taylor 2004;Shan and Yai 2011). This weakness indicated that traditional Chinese culture continues to be the dominant ideology, where Chinese citizens were unfamiliar with the practice of public participation. Therefore, certain affected communities protested to the government and the superiors of ACH, stating that the airport noise would affect their lives and health. Similarly, affected communities protested to the leaders of SHDC that the design scheme of the new building would affect their solar access and block their view. However, affected communities were willing to be involved in the process of public participation when Shanghai regional culture generated positive effects that lift their participatory awareness. By contrast, the majority of the public still lacked participatory awareness and were inactive in practice.

Influences of SR-PIMs on stakeholder behavior
Effective public participation that moves beyond the requirements of the law can benefit the participants and the outcome (Shepherd and Bowler 1997;Wu, Jia, and Mackhaphonh 2019). Motivation needs to exceed the compulsory legal requirements and private interests so that all participants endeavor to achieve decisions by PIMs that would maximize public interest and social welfare. Public participation in PIMs aims to maximize not only social responsibility by involving stakeholders but also public interest by reducing the adverse effects (Maddaloni and Davis 2017;Wu, Jia, and Zhang 2019), particularly for affected communities. In practice, SR-PIMs are the motivations of stakeholders to achieve effective public participation and high-quality decisions by PIMs. SR-PIMs guide stakeholders who actively implement, or are involved in, public participation and adopt responsible behaviors (Wu, Jia, and Mackhaphonh 2019). The public was inactive in the practices of AEP and CHEP because they lacked motivation and were unaware of their social responsibility. Sun et al. (2016a) showed that lead agencies and governments must shoulder more social responsibilities instead of focusing on meeting economic and technical requirements (Ninan, Mahalingam, and Clegg 2019). The affected communities ought to negotiate with other stakeholders (specifically the lead agency) through public participation rather than petitions or protests.
SR-PIMs reconciled the relationship between stakeholders by establishing a balance between public and private interests and professional and unprofessional backgrounds. Wu, Jia, and Mackhaphonh (2019) found that effective public participation depends on the maximization of public interests, which often contradicts that of private interests, such as the economic interests of corporations, the political purposes of officials, and personal selfishness. As the representatives of the cognition among stakeholders, SR-PIMs make stakeholders increasingly concerned over public interests while pursuing their private interests (Zeng et al. 2015). The public does not fully understand certain decisions of PIMs on complex and technical levels (Flavio et al. 2018), whereas experts and decision makers cannot comprehend the claims of the public and affected communities (Sun, Zhu, and Chan 2016b). Decision makers are responsible for explaining their professional decisions in understandable ways, and the public and affected communities are responsible for learning certain special knowledge of PIMs. SR-PIMs serve as a motivation for the responsible behaviors of stakeholders and address the limitations of formal institutions.

Influences of culture on stakeholder awareness
Culture influences the participatory awareness of stakeholders and the distribution of power in decision making in PIMs. To some extent, the elements of culture forge the power structure in decision making. Cultures with the elements of democracy and a bottom-up decision model, along with cultural tension, exert a positive effect on the participatory awareness of stakeholders (Boyle 1998), who are willing to be involved in the decision-making processes of public affairs. By contrast, compliance and topdown decision models continue to be dominant in traditional Chinese cultures (Tang, Wong, and Milton 2008;Shan and Yai 2011), and these elements negatively affect the participatory awareness of stakeholders.
In AEP and CHEP, participatory awareness of stakeholders is changing with the proceeding of public participation, and the influence of culture has altered different stages of the practice. Figure 5 shows the change in participatory awareness of stakeholders during the lifecycle of public participation and the critical value of cultural tensions that determine the dimension of cultural tension. Here, governments and lead agencies are consistently negatively affected by organizational cultures, and the public is consistently negatively affected by traditional Chinese culture. Affected communities experienced a change from the negative effects of traditional Chinese culture to the positive effects of Shanghai regional culture. Public participation follows the process of experience from start, conflict, negotiation, and finish, in which different types of culture affect the participatory awareness of stakeholders. Evidence from the influence of culture in AEP and CHEP suggests that participatory awareness of affected communities could be significantly raised in practice. Culture determines the model of decision-making and the way of power distribution that influences the participatory awareness of stakeholders (Dai et al. 2022). The Chinese government and state-owned enterprises (e.g. ACH and SHDC) were organized in a hierarchical structure that is fundamentally adaptive to the top-down decision model in public affairs. Top-down decision models of PIMs have been incorporated into organizational cultures. Thus, governments and lead agencies try to maximize their decision-making power by meeting the basic legal requirements (Johnson 2010). Moreover, in China, the government has the paternalistic authority to make decisions. The compliance in cultures enables Chinese people to be accustomed to accepting the arrangements of the government (Li, Ng, and Skitmore 2012), and their participatory awareness in public participation is weak, as shown by the public in AEP and CHEP.

Informal institutions coordinating stakeholder relationships
Informal institutions are the component of the institutional environment that establishes the rule structure for the practice of public participation in PIMs and gain importance once formal institutions are absent or weak (Sauerwald and Peng 2013). The case studies of AEP and CHEP showed that informal institutions through culture and SR-PIMs influence the participatory awareness and behaviors of stakeholders (Wu, Jia, and Mackhaphonh 2019;Dai et al. 2022), respectively, in the practice of public participation. In Figure 6, the appearance frequency of the circles represents the odds of participatory awareness and responsible behaviors of stakeholders under the different effects of SR-PIMs and cultural tension, respectively. That is, effective public participation entails that a high level of SR-PIMs guides stakeholders to undertake responsible behaviors and that positive cultural tension enables broad participation by generating participatory awareness. The Shanghai regional culture makes local residents form shareholder coalitions, which is the shared understanding among shareholders regarding the central and enduring characteristics of the group (Sauerwald and Peng 2013). In the cases of AEP and CHEP, inclusive and personal rights as the elements in the Shanghai regional culture make the affected communities emerge as stakeholder coalitions to petition the leaders of ACH and SHDC to influence the decisions of the two PIMs. To alleviate the conflictual relationship, lead agencies have guided the affected communities to be involved in the process of public participation and redistribute the power in decision-making processes. That is, cultures must be compatible with the spirit of public participation, and cultural tension generates a positive effect on the participatory awareness of stakeholders.
Effective public participation in PIMs entails that participatory awareness turns into responsible behaviors (Wu, Jia, and Mackhaphonh 2019), which is essential to coordinate the relationship of stakeholders. In the cases of AEP and CHEP, the leaders of ACH and SHDC emphasized the importance of SR-PIMs when laws and regulations were weak to confine the irresponsible behaviors of stakeholder coalitions. ACH and SHDC realized that the results of public participation must meet the legal requirements and fulfill the contents of SR-PIMs. That is, stakeholders understand the necessity of PIMs and adopt responsible behaviors (Kirkman and Voulvoulis 2017). Moreover, Figure 6. Effect mechanism of informal institutions. evidence of SR-PIMs in the AEP and CHEP showed that social responsibility partly helps cultural tension to have positive effects on stakeholders.

Conclusions
The paper designed a double-case study and selected two cases from Shanghai to investigate the effects of informal institutions on stakeholder and public participation in PIMs. The case studies of AEP and CHEP have produced answers to the three key research questions. (1) SR-PIMs guide participants to adopt responsible behaviors beyond the basic legal requirements and reduce the contradictions between private and public interests, professional and unprofessional knowledge. (2) Culture determines the decision model and distribution of power in PIMs. Core elements in cultures determine the dimensions of cultural tensions that exert effects on the participatory awareness of stakeholders.
(3) Advocating SR-PIMs and using positive effects of cultures are the ways for informal institutions to help to alleviate the conflicts in PIMs by reconciling the relationship among stakeholders.
The present study contributes to the body of knowledge by explaining the effects of informal institutions on stakeholders and public participation of PIMs by investigating the effects of SR-PIMs and culture. For the stakeholders in public participation in PIMs, SR-PIMs must be fulfilled in guiding responsible behaviors, and culture should generate a positive tension to enable participatory awareness. The findings help policymakers revise laws and develop pertinent strategies to promote participatory awareness and responsible behaviors by stakeholders, to which the effects of informal institutions must be inclusive in the practice. Lead agencies and governments should act beyond the legal requirements and change their decision modes to mobilize the public and affected communities should be positively involved in the practice.
The findings from this study are not conclusive. Two PIMs were investigated in the context of China, but different national conditions and legal systems entail diversity and differences in the effects of informal institutions. In the future, additional data should be collected and further case studies should be conducted to validate the proposed theoretical framework and enhance its generality. The challenge is to determine how to develop a participatory culture and SR-PIM evaluation system to form participatory awareness and responsible behaviors, which is the key to practice.

Disclosure statement
No potential conflict of interest was reported by the author.

Supplemental data
Supplemental data for this article can be accessed online at https://doi.org/10.1080/09640568.

2022.2038094
Funding This research is supported by the "Fundamental Research Funds for the Central Universities" No. 30921012208, "Excellent Youth Project of Hunan Provincial Department of Education"