The role of fairness in multi-tier sustainable supply chains

Fairness is an important topic that forms part of an organisation’s sustainability practice and agenda, particularly from a social dimension. However, past studies have rarely considered the role of fairness as a driver of sustainability in multi-tier supply chains. The purpose of this paper is two-fold. First, it examines the impact of fairness perceptions on the relationship between multi-tier supply chain partners. Second, it investigates the dynamics of on-going fairness formations in different stages of the vibrant multi-tier supply chain relationship development process. These gaps have been addressed by reporting the findings of qualitative research. Primary data were obtained from 18 procurement and supply practitioners of buying firms and their top tier-1 & 2 suppliers. Findings show that fairness perceptions have an impact on collaborative activities between multi-tier supply chain partners. These collaborative responses such as information sharing, joint relationship effort, and dedicated investment can also impact critical aspects of the multi-tier supply chain relationship such as trust, commitment, satisfaction, and conflict resolution. The findings show that multi-tier supply chain partners have different expectations but usually evaluate fairness at the review phase of the relationship development process. These considerations offer theoretical and practical guidance towards the advancement of sustainable multi-tier supply chain relationships.


Introduction
Establishing multi-tier supply chain (MTSC) relationships globally have become very popular for organisa tions seeking to save costs or create a potential competitive edge (Jia, Gong, and Brown 2019;Sarkis, Gonzalez, and Koh 2019;Villena and Gioia 2020). However, such MTSC relationships do not often meet their set targets because of possible reputational risks arising from actions linked with triple bottom line standards (Siano et al. 2017). Literature has stressed the significance of exhibiting socially sustainable practices that will enhance the growth of MTSCs (Mena, Humphries, and Choi 2013;Sarkis, Gonzalez, and Koh 2019). From a social supply chain management (SSCM) perspective, such actions include unfair practices, opportunistic acts, corruption, fraud, and behaviour that hinder fair outcomes in relationships (Alghababsheh, Gallear, and Rahman 2018;Alghababsheh and Gallear 2020).
A few studies (e.g. Mena, Humphries, and Choi 2013;Bai et al. 2019;Orji, Kusi-Sarpong, and Gupta 2019;Kusi-Sarpong, Gupta, and Sarkis 2019;Govindan, Shaw, and Majumdar 2020) have considered the social dimension of supply chain (SC) relationships in the MTSC context. However, from a social perspective, scant studies in the literature have taken further steps to examine how perceptions of fairness influence MTSC relationships. The concept of fairness is an important notion that influences all social and economic exchanges (Liu et al. 2012). Likewise, SC relationships as social transactions require partners to behave in a manner that is fair, in order to be beneficial (Narasimhan, Narayanan, and Srinivasan 2013). Accordingly, attitudes and behaviour are pursuant to fairness, which if neglected, can nurture opportunism (Trada and Goyal 2017;Tran, Gorton, and Lemke 2021), weaken trust (Kumar 1996;Samaha, Palmatier, and Dant 2011), increase potential conflicts, stir relationship problems and unrest (Tóth et al. 2018;Tura, Keränen, and Patala 2019), and ultimately affect relationship outcomes (e.g. terminations intentions) (Yang et al. 2012;Fawcett et al. 2015).
Based on the social exchange theory (SET), transacting parties interact with each other because they expect rewards and anticipate the avoidance of punishment (Emerson 1976). SET explains that the behaviour of SC partners is determined by their perceived relationship quality (Blau 1986), which usually entails comparing the rewards and costs involved in these interactions (Luo et al. 2015). Thus, social forces such as fairness are crucial for maintaining MTSC relationships, since SC partners often judge their received profits in relation to their investments (Kumar, Scheer, and Steenkamp 1995). SET adds to the fairness agenda by viewing SC relationships as social exchange systems where SC partners expect to receive rewards from interactions with their partners. Such events can positively influence relational attitudes and behaviour which can improve the strength of communication, trust, commitment, and others, between SC partners. Thus, SC partners' behaviour and attitudes are stimulated through their perception of fairness.
Most studies have focused considerable attention on the relationship between single firms and their direct customers or suppliers (Martins and Pato 2019), whilst only a few have considered the perspective of MTSCs (Tachizawa and Wong 2014;Wilhelm et al. 2016;Bai et al. 2019;Govindan, Shaw, and Majumdar 2020). This study examines the exchange relationship between U.K. manufacturers (buyers) and their Tier-1 and Tier-2 suppliers in India. This context is important because many leading manufacturers continue to expand their supply base in India due to their recent and future development prospects (Mehta and Rajan 2017). Likewise, having suppliers situated in different regions of the world, and those suppliers having their own suppliers makes the supply network complex to manage, difficult to meet expectations of others, and stresses the need to go beyond the Tier-1 supplier in the approach to managing supply chains (Gong et al. 2018;Villena and Gioia 2020;Yoon, Talluri, and Rosales 2020). Respecting and upholding dimensions of fairness becomes a crucial aspect when managing the relationship between multi-tier SC partners (Hartmann and Moeller 2014;Alghababsheh, Gallear, and Rahman 2018;Zhou, Govindan, and Xie 2020).
The notion of fairness has attracted increased significance in organisational research (Adams 1965), and has become an increasingly visible construct in social sciences over the past four decades (Colquitt et al. 2001). Prior to 1975, research on fairness was predominantly focused on the distribution of outcomes (distributive fairness) (Adams 1965). After 1975, Thibaut and Walker (1975) introduced the study of process (procedural fairness) to the literature on fairness. In 1986, Bies and Moag (1986) advanced fairness literature with a focus on the significance of the quality of interpersonal treatment that people receive, when procedures are implemented (interpersonal fairness). In recent years, scholars have become increasingly concerned with the idea of fairness, in the SC context since SC partners are often in different positions of power (Gorton et al. 2015), which often exposes the weaker party to vulnerabilities (Kumar 1996;Duffy et al. 2013). Fairness is concerned with how SC partners treat one another in their social and economic interactions. Based on the above discussion, this research aims to expand knowledge on social issues such as fairness to the multi-tier SC level. Specifically, it draws on the relevant fairness literature in the SC domain and uses the SET to develop a conceptual model in which we propose that fairness (i.e. distributive, procedural, and interactional), as perceived by members of the MTSC relationship can serve as a driver of collaboration, and potential relationship development. It also highlights the different stages of relationship development which MTSC partners' experience, and reveals how the perceptions of fairness evolve, are formed, and are manifested in these different stages.
In doing so, this study addresses the following research questions: This study holds theoretical and practical contributions. For theory: (1) it is one of the first, if not the first empirical effort that applies the lens of SET to investigate SSCM in the MTSC context (2) it adds to the current debate on the social dimension of MTSC relationships by revealing how fairness perceptions influence behaviour and attitudes of MTSC partners in the exchange relationship setting; (3) it reveals the different phases of MTSC relationship development (initiation, implementation, and review), and highlights how perceptions of fairness are manifested at these different phases; For managers: (4) it reveals why more investment and effort should be allocated to promoting fairness in MTSC relationships for the development of long-term advantages; (5) the MTSC perspective also gives managers a wider approach to promoting fair practices since it is extremely difficult to control the unfair practices at a multi-tier level.
The paper proceeds as follows: firstly, the theoretical underpinnings and a review of relevant literature; secondly, the research design and methodology adopted, the data collection technique used, and the data analysis approach; thirdly, the findings of the study and concluding remarks with implications for theory and practice which can indicate directions for future research.

Social exchange theory
Social sustainability considers the aspects of product and process that influence the people involved in supply chains, focusing on the human aspect (Hussain et al. 2018;Mani and Gunasekaran 2018). SET (Emerson 1976) is adopted as a theoretical lens to understand the role of fairness in MTSC relationships. The logic is linked with the idea of sustainable long-term relationship development. From this perspective, two main concepts are considered: the level of collaboration, and the relationship quality and development between MTSC partners. SET claims that individuals or corporate firms interact for rewards or with the expectation of a reward from their interchange with others and avoidance of punishment (Emerson 1976). SET argues that attitudes and behaviour are determined by rewards of interaction between individuals in relationships. Thus, boundary spanners (relationship managers) are willing to commit to such relationships because cooperation is initiated based on the expectation that an individual firm's contribution will be reciprocated in the future by its receptor (Lu 2006;Luo 2007). The reciprocity between SC partners is an independent transactional exchange (Gouldner 1960), where one party's actions depend on another party's behaviour. This implies that firms are more likely to maintain relationships if they perceive themselves to be receiving fair treatment (Lind and Tyler 1988).
The concept of fairness is an important dimension of SSCM because it is a social force that can help MTSC partners maintain long-term orientation (Govindan, Shaw, and Majumdar 2020;Zhou, Govindan, and Xie 2020). A MTSC partner will be encouraged to share more information, put more effort, and dedicate higher investments into a relationship based on their perceptions of fair treatment. In such circumstances, a manufacturer (buyer) may decide to increase the percentage of a category to be sourced from the supplier, subject to the dependency level (Zaefarian et al. 2016). This profound effect may also influence the supplier's behaviour, possibly resulting in continuous commitment and relationship development (Liu et al. 2012).
As emphasized in the current literature, considerable theoretical frameworks have been adopted to examine the issues of sustainability in the multi-tier SC context (e.g. Tachizawa and Wong 2014;Dubey et al. 2017). However, most published studies lack an inclusive framework which considers the social behaviour in interactions between parties in an exchange relationship from a distributive, procedural, and interactional perspective. SET is relevant in the context of this research as it lays emphasis on the significance of fair interactions during exchanges between MTSC partners. SET emphasizes the vital role of fairness as a factor that can influence the behaviour of MTSC partners, while creating more socially sustainable supply chains. Since MTSCs require the involvement, coordination, and collaboration of SC partners, the role of people and decisionmakers in the relationship development process becomes important in the development of sustainability in MTSC relationships.

Fairness in the multi-tier supply chain context
The extant literature has focused considerable attention on socially sustainable SC practices in tackling current social issues of suppliers, but the root causes of these issues have unexpectedly been neglected (Alghababsheh, Gallear, and Rahman 2018). It has been highlighted that such social issues such as weak regulations, high labour intensity, and poor payment schemes (Huq, Chowdhury, and Klassen 2016), are often motivated by the buyer's unfair trading practices. In turn, suppliers may feel the need to transfer part of the pressure down to their second-tier suppliers to cope with persistent cost cutting measures from buyers (Klassen and Vereecke 2012). Changes in the market such as demand uncertainty, technological landscape, consumer requirements, and diminishing product life cycles, also drive buyers towards exhibiting practices that may be perceived as unfair by suppliers (Awaysheh and Klassen 2010;Lu et al. 2018). The value derived from fairness perceptions in the SC context has been evidenced, based on the extent to which distributive, procedural and interactional fairness are established (Bouazzaoui et al. 2020).
Distributive fairness (DF) was defined by Adams (1965) as equity, signifying its existence when a person, for his or her own situation, perceives that the ratio of outcomes to inputs are equal to the ratio of outcomes to inputs of others. In the SC context, the performance outcomes in the relationship are deemed fair, if investments in effort and resources compare favourably with outcomes. The focus of distributive fairness relates to how the benefits and risks are shared between the buyer and supplier (Griffith, Harvey, and Lusch 2006). This aspect of fairness is linked with the idea of equity theory, which emphasizes that MTSC partners want fair and equal distribution of resources and relationship outcomes.
Procedural fairness (PF) which is derived from the idea of instrumentality (Luo 2007), focuses on the consistency in decision-making. It suggests that people are often concerned about fairness in the process, and they will view procedures as fair if they perceive that they have control over the process (Gibson 1989). In the MTSC context, procedural fairness relates to the following activities: the consistency of the buyer's purchasing policies, the degree to which a supplier can question and challenge a buyer's policies, or the extent to which a buyer or supplier provides rational explanations for certain decisions made (Kumar 1996).
Interactional fairness (IF) is anchored in the idea of social exchange (Luo 2007), representing the social aspects of fairness, which relates to people's reactions during interpersonal and social interactions (Colquitt et al. 2001). The interpersonal treatment and communication received during interactions are important factors which lead to perceptions of fairness (Tyler and Bies 1990). This social dimension of fairness concentrates on interpersonal treatment, conduct during human interactions, and concerns of open communication of information (Tyler and Bies 1990). In the MTSC context, interactional fairness refers to the actions, and the degree of interpersonal sensitivity that a supplier's employees exhibit towards the representatives of a buyer and vice versa (Zaefarian et al. 2016). It relates to the social glue of the inter-firm exchange such as politeness, honesty, dignity, and empathy (Greenberg and Cropanzano 1993).
Overall, these dimensions of fairness are critical for developing the social dimension of MTSCs relationships as they focus on ethical rules and fair standards. For example, DF can minimise the likelihood of opportunism in the relationship and stimulate efforts between MTSC partners (Luo 2007;Trada and Goyal 2017). Similarly, PF can aid in providing a 'voice' to the MTSC partners, especially the weaker parties, and help in promoting superior performance (Folger 1977). Likewise, IF can promote harmony, reduce conflict, and improve collaboration between MTSC partners (Luo 2007). Although these factors are important, they have not frequently appeared in the literature on the social factors of MTSC management (Alghababsheh, Gallear, and Rahman 2018).

Collaboration and relationship quality between multi-tier supply chain partners
The relationship between MTSC partners requires a close collaboration to achieve sustainability targets (Bai et al. 2019;Villena and Gioia 2020;Yoon, Talluri, and Rosales 2020). Collaborative activities represent each party's willingness to give and take in the relationship, which allows it to adapt over time, and creates an avenue for ongoing administration of the exchange (Tyrrell 2020). In this research, three key collaborative activities are considered: information sharing, joint relationship effort, and dedicated investment, as they represent value-adding relational norms (Cao and Zhang 2011).
MTSC relationships require some form of information sharing (Viswanathan, Widiarta, and Piplani 2007). It is considered one of the building blocks of a solid MTSC (Yoon, Talluri, and Rosales 2020), and a critical factor if SC partners want to realise relationship benefits (Kembro, Näslund, and Olhager 2017). To meet set targets in the relationship, a joint effort is required by MTSC partners (Viswanathan, Widiarta, and Piplani 2007). A joint relationship effort has an impact on the success of MTSC relationships through the working together of SC partners towards decision-making and joint-problem-solving, planning and coordinated activities (Nyaga, Whipple, and Lynch 2010). MTSC relationships also require dedicated investments which have a huge impact on sustainable relationships through sufficient resource investments (Min et al. 2005). These investments have been recognised to communicate a strong commitment to the relationship, because of the economic consequences that SC partners will incur if it ends (Nyaga, Whipple, and Lynch 2010). In this research, it is argued that fairness perceptions may influence the level of collaboration between MTSC partners.
The relationship quality between MTSC partners is also crucial for long-term sustainability (Huntley 2006). Most studies in relationship marketing view this quality as a concept that echoes issues relating to trust (Morgan and Hunt 1994), commitment (Kumar, Scheer, and Steenkamp 1995), and satisfaction (Garbarino and Johnson 1999). Trust constitutes the belief, attitude, or confidence in another party (De Ruyter, Moorman, and Lemmink 2001). It is the belief that another company will perform actions that will result in a positive impact for the firm (De Ruyter, Moorman, and Lemmink 2001). The presence of trust in SC relationships has been revealed to reduce transaction costs and establish a positive environment for doing business (Qian et al. 2020). Commitment refers to how exchange partners are willing to make short-term sacrifices to develop and maintain long-term, stable, and profit-making relationships (Anderson and Weitz 1992). Satisfaction is a positive state which involves an evaluation of all aspects of a firm's working relationship with another firm (Anderson, Håkansson, and Johanson 1994). Overall satisfaction has been revealed to guide decision-making and predicting behaviour in relationships (Garbarino and Johnson 1999).
Through collaboration, MTSC partners can work as if they were a part of a single enterprise. To ensure that MTSC partners work in close collaboration, a strong relationship between MTSC partners characterised by high levels of trust, commitment and satisfaction are essential. However, by collaborating with autonomous firms, SET emphasizes that concerns can arise about the fairness between SC partners (Huo, Wang, and Tian 2016). Thus, we argue that perceiving fairness plays an important role in the relationship development process, promoting the development of trust, commitment, and overall satisfaction in such MTSC relationships.

Relationship development process in the multi-tier supply chain context
From a process viewpoint (Dwyer, Schurr, and Oh 1987), a MTSC relationship can be observed as a sequence of relationship stages through which interactions happen (Liu et al. 2012). An inter-organisational relationship framework was developed by Frazier (1983), and Frazier, Spekman, and O'Neal (1988). It was divided into three phases: initiation, implementation, and review stages.
The initiation phase focuses on why and how firms seek to initiate exchange relationships (Frazier 1983). It commences with the buyer when they perceive a need which creates the motive to form an exchange relationship (Foa and Foa 1974). The implementation phase starts when products, services, and related information are initiated between the exchange partners, and ongoing interactions occur between each firm's representatives (Frazier 1983). In the MTSC context, the buyers will start forming perceptions of the suppliers' role performance, how well they carry out their chain role, and vice versa. When the role performance of a MTSC partner is below prior role expectations, this can lessen the dependence on the exchange partner from the initial level (Frazier 1983). The review process involves an appraisal of the rewards or losses realised by each exchange firm in the exchange. It is suggested that fairness perceptions are developed mostly in the review stage, when rewards (losses) are compared to inputs (Frazier 1983;Frazier, Spekman, and O'Neal 1988).
A contrasting perspective divides the relationship development process into five general phases; awareness, exploration, expansion, commitment, and dissolution (Dwyer, Schurr, and Oh 1987). Each phase represents a major transition in how parties regard one another. The dissolution is the last phase which entails the possibility of withdrawal or disengagement from the relationship (Dwyer, Schurr, and Oh 1987). At this point, the basic exchange calculus theory is relied upon, which could result in consequences such as relationship termination (Emerson 1976). See (e.g. Dwyer, Schurr, and Oh 1987;Frazier 1983;and Frazier, Spekman, and O'Neal 1988) for a comprehensive overview of inter-organisational relationship development.
These studies seem to propose that the perceptions of fairness are formed in a single (and different) stage of exchange relationships. However, past research has not investigated whether this is the case, or whether the perceptions of fairness are formed at every single stage but exert different degrees of importance in affecting the behaviour of exchange partners (Liu et al. 2012). Likewise, the role of MTSC partners in managing the dissemination of social SSCM practices (e.g. exhibition of fairness) through the relationship development process is an important consideration. Even though past studies (e.g. Wilhelm et al. 2016;Gouda and Saranga 2018;Hannibal and Kaupi 2019;Jabbour, Jabbour, and Sarkis 2019;Feng, Hu, and Orji 2021) investigated possible solutions to sustainability issues in MTSC relationships from different angles, to date, no available published study has proposed a comprehensive theoretical framework which includes issues relating to perceptions of fair treatment. This study is different from past studies in the MTSC context, as it includes considerations relating to how perceptions of fairness can impact collaborative responses and relationship development, and how perceptions of fairness are manifested in different phases of the MTSC relationship.

Research context
This research focuses on the exchange relationship between U.K. manufacturers (buyers) and their Tier-1 and Tier-2 suppliers in India. The manufacturing industry is one of the largest and fastest developing industries in the U.K. and India, and both countries are among the top manufacturing nations in the world with a combined manufacturing output of more than US$500 billion (Innovate UK 2017). Recognising the U.K. Government's effort to halt its long-run decline, manufacturing still makes a disproportionate contribution to the U.K. economy (Harris and Moffat 2019). Evidence shows the U.K. retained its position globally as the 9th leading manufacturer and 10th in terms of global exports with output, totalling £191 billion in 2019, revealing an increase of 7% over the last five years (Tyrrell 2020). Although India is an emerging market and developing economy, its place in global manufacturing has risen to 6th position with more potential for future growth (World Economic Forum 2020). India's manufacturing sector is one of the fastest growing in the world with a revenue potential of 1 trillion USD by 2025. Thus, U.K. manufacturers are constantly seeking opportunities to expand their supply chains to the rapidly growing Indian market, with increasing demand for high-quality products. As a result, there are several inter-organisational exchanges and collaborations that occur between U.K. manufacturers (buyers in this context) and suppliers in the 1st and 2nd tier in India.

Philosophical stand and research methods
A qualitative approach was adopted because we wanted to obtain rich insights from an examination of the 'multitier' level of analysis (Merriam and Tisdell 2015;Creswell and Poth 2016). Given the fact that limited research has been done in this area, we believed this approach would allow us to uncover the role of fairness perceptions in the development process of MTSC relationships, and explore how fairness impacts on the collaboration between MTSC partners. Our philosophical stand also informed our choice of research method. Since our belief is that knowledge is shaped by culture and society (Brunt, Horner, and Semley 2017), we adopt the nominalism ontology which implies that reality does not exist independently of our perceptions and meanings (Easterby-Smith et al. 2021). Based on our constructivist epistemology, we believe that our reality is socially constructed by social actors who require engagement to explain how and why reality is formed the way they see it (Lincoln and Guba 2013). Our research strategy was inductive in nature (Blaikie 2010;Collis and Hussey 2014), utilising semi-structured interviews, and analysing and comparing the insights obtained from SC and procurement practitioners.

Research process and sampling strategy
An invitation letter was chosen to approach participants about the nature of the research. This allowed them to read and acknowledge an informed consent document which stated how the data would be stripped of all identifying information, and kept in strict confidence (Easterby-Smith et al. 2021). We obtained a list from the industrial database of the British Chamber of Commerce which consisted of firms in the U.K.'s manufacturing sector. We also created criteria to guide the selection of respondent firms such as: • being able to voluntarily disclose information to assist the research; • having a multi-tier SC structural arrangement (i.e. buyer-supplier-supplier relationship) with tier-1 and tier-2 suppliers in India; • having a multi-tier collaboration more than 2 years old, for sufficient depth to cover the different aspects of the research; • focal companies willing to give access to their SC members in at least two tiers of suppliers, and these firms further down the chain willing to participate in the research.
The semi-structured interviews offered in-depth insights about the topic (Pietkiewicz and Smith 2012). We utilised an interview guide to ensure that all aspects of the research questions were covered, and to ensure comparability of answers. The prior literature on MTSCs (Viswanathan, Widiarta, and Piplani 2007;Tse and Tan 2011;Lyons and Ma'aram 2014;Yoon, Talluri, and Rosales 2020) was used to develop the interview questions. We conducted all interviews in English and each interview lasted between 45 and 60 minutes. The questions discussed were related to the impact of perceptions of fairness on the MTSC relationship, and how the perceptions of fairness are manifested in different stages of the MTSC relationship.
A purposive sampling strategy was adopted in this research (Blaikie 2010). The sample consisted of participants (SC practitioners) who volunteered to take part in the research by answering requests to participate in the study. The unit of analysis was a buyer-suppliersupplier relationship involving the interaction between manufacturers (buyers) and their Tier-1 and Tier-2 suppliers in India. The suppliers were responsible for sourcing and procurement of raw materials essential for the production and onward movement of finished goods down to the manufacturer (buyer). We selected Tier-1 and Tier-2 suppliers based on the closed structure of their MTSC, where Tier-2 suppliers also have a formal linkage and interaction with the buyer (Mena, Humphries, and Choi 2013). A total of thirteen manufacturing companies (focal buying firms) in the U.K. were approached, but some companies were dropped due to their inability to meet the set criteria for data collection. Eventually, six U.K. manufacturing firms (Buyers A to F) participated and gave us access to their MTSC, which consisted of their suppliers (Tier-1 suppliers for Buyers A to F), and their supplier's supplier (Tier-2 suppliers for Buyers A to F). Table 1 illustrates the basic details of the companies that took part in this research. Due to the promise of anonymity and confidentiality, we could not reveal any names of the participants' firms at all levels of the MTSC.
To reduce respondents' bias, we interviewed multiple subjects who had adequate knowledge regarding MTSC management. A total of eighteen interviews conducted between April 2019 and July 2020 were eventually utilised. The interview sessions were audio-recorded and transcribed for accuracy and clarity of information ( Table 2).
The interviews were concluded when we reached theoretical saturation, where subsequent interviews would offer no new insights towards understanding the research question (Eisenhardt 1989). Apart from formal interviews, a member of the research team also had informal discussions and field trips with buyers in the U.K., while another member did likewise with suppliers in India.

Data analysis
After obtaining our data, we analysed it following a deductive process using the thematic analysis approach (Easterby-Smith et al. 2021). The researchers familiarised themselves with the data through a transcription process. The task was divided into three steps: data reduction, data display, and conclusion, as suggested by Miles and  Kumar, Scheer, and Steenkamp (1995) The effects of perceived interdependence on dealer attitudes Automobile industry in the U.S.A.
Distributive fairness and procedural fairness moderator -environmental uncertainty Willingness to invest in the relationship, expectation of continuity Survey: regression analysis Procedural fairness is valued by resellers more than the distributive fairness in evaluating their relationship with the manufacturer or supplier Griffith and Lush (2000) An examination of the influence of procedural justice on long-term orientation in wholesalersupplier relationships   Huberman (1984). We grouped and coded the raw transcribed data (word, sentences and paragraphs) related to the research questions (first-order codes).
In line with the research questions, we divided the analysis process into two main parts. The first part analysed data in relation to how perceptions of fairness impact the relationship between MTSC partners. At this stage, the analysis focused on the specific impact of fairness perceptions on collaborative activities between MTSC partners in line with the reviewed literature. We broke down first-order codes into descriptive second-order categories such as 'on-time communication and information sharing', 'relationship investments', and 'working together' (see Table 3 for examples of coding). We then juxtaposed the two-independent analysis in relation to SC collaborative activities (Cao and Zhang 2011), and dimensions of fairness (Narasimhan, Narayanan, and Srinivasan 2013) to explore how specific dimensions of fairness influence collaborative activities. This enabled us to understand the different collaborative activities that were related to fairness dimensions.
Towards an understanding of the impact of fairness on MTSC relationships, a further aspect of the data analysis focused on the specific impact on the relationship between MTSC partners. First-order codes were placed into descriptive second-order categories such as 'going the extra mile', 'breach of trust', 'satisfaction level', 'minimising conflicts', 'continuity', 'length of the relationship', and 'credibility and reputation'. Next, we juxtaposed the two-independent analysis in relation to SC relationship success measures (Palmatier, Scheer, and Steenkamp 2007), and fairness perceptions to explore how dimensions of fairness impact relationship outcomes (see Table 4 for examples of coding).
The second part analysed data in relation to how perceptions of fairness are manifested in different stages of the MTSC relationship development process (see Table 5 for examples of coding). Accordingly, we summarised initial conclusions on this aspect for each respondent firm in narratives by identifying patterns that could explain the specific stage that perceptions of fairness are formed in line with the reviewed literature.
Measures were taken to safeguard the trustworthiness of the data and their analysis. We related our data and findings to the pertinent literature and theoretical frameworks. The findings were also cross-checked by two anonymous researchers (independent coders) with experience in analysing qualitative interviews, to help achieve reliability of data through an inter-coder exercise (Miles and Huberman 1994). The process of inter-coder reliability began with the random evaluation of interview transcripts by the independent coders using a coding outline. Afterwards, the interview transcripts were coded independently and the views of the independent coders were deliberated with the research lead. In the final coding phase, the inter-coder reliability index was calculated based on a division of the overall number of agreements for all codes by the total number of agreements and disagreements for all the codes (Campbell et al. 2013). The reliability score was 84% (above the 80% threshold) which is deemed to be satisfactory for exploratory research (Miles and Huberman 1994). We then shared the coding summary with the study participants and asked them to comment on the overall conceptualisation and the proposed codes. Twenty-two participants responded and suggested minor changes to wording of the codes. After making these changes, we presented our work in various academic conferences and received several recommendations. These steps confirmed that the codes and categories represent the key variables of this study.
Because of the in-depth qualitative rather than quantitative nature of the obtained data, the emphasis in this

Risk sharing and problem solving
If a buyer has a problem and they resolve it very quickly, I will use them time after time again. (Tier-1 Supplier for Buying Firm C)

Problem solving
We have had buyers purchase our product with a fantastic price and a fantastic quality but when something went wrong, they start blaming us for everything and it takes months to sort out, I'll think twice before using them again. (Tier-1 Supplier for Buying Firm E)

Problem solving
Our perception of fairness will also influence on the motivation to work together in the supply chain mainly.
(Tier-2 Supplier for Buying Firm B)

Mutual working together
But it just showed to us that when a problem arose, they weren't prepared to be fair to us even though they had agreed to our terms and conditions when it came to a critical point, they didn't respect the terms and conditions they signed up to. (Buying Firm F)

Knowing situations and processes
So, taking ownership and responsibility is a vital collaborative activity which links to some sort of relationship effort. (Buying Firm E)

Responsibility and ownership
These problems are mostly because some supply chain partners (especially powerful buyers) don't adhere to the initial agreements on the contracts signed before we begin our relationship and collaborations is very inappropriate, unprofessional and unfair. (Tier-1 Supplier for Buying Firm F)

Adherence to agreements
Working together is also another aspect that could be affected by perceiving fairness. (Tier-2 Supplier for Buying Firm F) Working together Table 4. Excerpts relating to how fairness perceptions impact multi-tier supply chain relationships.
Data reduction (first-order codes) Descriptive code (second-order categories) Fairness components (third-order theme) We are more inclined to go the extra mile for someone that is treating you fairly. (Tier-2 Supplier for Buyer E) Going the extra mile Relationship commitment Yes, our perception of fairness impacts on our collaboration with our supply chain members particularly with the behavioural aspect as your attitude changes towards aspects such as effort and commitment. (Tier-1 Supplier for Buyer E)

Effort and commitment
For example, of one of our supply chain partners (supplier), as far as we are concerned regardless of the fact that we are in a relationship with them, they are not entirely fair to us because they don't meet deadlines, they don't meet lead times, they don't meet delivery dates and KPIs, and for these reasons we don't believe they are committed to the relationship, in fact it is very clear. (Buying Firm E) Effort and commitment Our perception of fairness will also influence on the motivation or commitment to work together in the supply chain. (Tier-1 Supplier for Buying Firm A)

Motivation and commitment
The first impact is having a trust level, but once you have got a level of trust, your ability to try and evaluate and understand fairness between two businesses becomes easier. (Tier-2 Supplier for Buyer F)

Trust level Trust level
Businesses don't often do things for the good anybody, they are doing it for business reasons so would I terminate contract if there was a breach of trust, the answer is absolutely. (Buying Firm F)

Breach of trust
For example, if a supplier has let us down, it can be because they have handed over confidential information from their company onto a third party which wouldn't go down very well with us because some of the work that we do is highly confidential, so trust is the biggest factor that our perception of fairness would link to the most. (Buying Firm F) Breach of trust I know trust builds over time but when we perceive unfairness, it influences on the trust level straight away and if I had to endure due to lack of options, then I would be very careful with them. It will obviously take time and a series of unfair or fair treatments to know which direction the trust impact would lead to.

Satisfaction level Relationship satisfaction
When they give us fair price, we tend to work more closely with them, and you have that feeling they are being fair, and they aren't ripping you off. (Tier-1 Supplier for Buying A)

Ripping off
So, if there is a lot of fairness, we will bond with them and the relationship and partnership will flourish and our overall satisfaction as a firm and with the relationship is also key.

Minimising conflict Conflict resolution
When our buyers exhibit fair behaviour, it reflects on minimisation of potential issues that may occur particularly with product specification because of the data they are willing to release to us. (Tier-2 Supplier for Buyer B) Minimising potential issues Why perceiving fairness in contrast to unfairness is very important is because it can help with avoiding any misunderstanding that would usually occur in the process. (Buying Firm C)

Avoiding misunderstanding
We have had our buyers treat us very badly in the past which resulted in a lot of arguments and conflicts regarding different disputes which we thought were unfair. (Tier-1 Supplier for Buyer B)

Arguments and conflicts
Perceiving fairness is like changing the gear from gear 1 to gear 2 if you were riding a car, it does have a very significant role on how we value that business through seeing that they value us with their fair dealings with us. (Tier-1 Supplier for Buying Firm D)

Relationship value Future collaboration intentions
Based on our past experience as a business and my own individual experience with individuals I dealt with before, I will not anymore transact with businesses who are not fair, I just wouldn't do it because it's just too difficult. (Tier-2 Supplier for Buying Firm D)

Continuity
We have terminated relationships with supply chain partners in the past based on how unfairly we were being treated by them, especially over time.

Reputational viewpoint
It also has an impact on firm reputation and image within the supply chain. (Buying Firm D)

Reputation and image
Asides from the reputational damage on the end consumers angle, don't forget that supply chain partners are also customers in some sense and reputation also glows along the chain as supply chain partners or businesses in general which make up a supply chain could perceive us to bad reputation in trading or dealing with businesses. (Buying Firm C) Reputation research is on analytical generalisation towards theoretical concepts, rather than statistical generalisation of quantitative type studies.

Findings
After analysing our data, we were able to unravel specific details on how fairness perceptions of distribution of rewards, processes and policies, and interpersonal treatment impact collaborative activities and the development of MTSC relationships. Furthermore, we found that perceptions of fairness are formed particularly at the evaluation stage of the MTSC relationship development process, where decisions are based on developed perceptions regarding the status of the relationship. The key results of the study are presented concisely in tables and figures.

Impact of perceptions of fairness on collaborative activities between multi-tier supply chain partners
Our findings indicate that collaboration between MTSC partners can be highly influenced by perceptions of fairness, and those perceptions can influence collaboration. The literature has stressed that collaboration between firms will normally include key activities not limited to information sharing, joint relationship effort and dedicated investments (Nyaga, Whipple, and Lynch 2010). We found that when fairness is perceived, either by the first or second tier supplier, the perception impacts strongly on the level of communication (information sharing), investment and contribution towards the relationship (dedicated investment), and determination to collectively work with the buyer (joint relationship effort). These perceptions of fairness by individual firms, are based on a series of exchanges and interactions in the closed MTSC, and which have a critical role in improving the level collaboration and partnership in the multi-tier channel. The interviews revealed that whilst the perceptions of fairness can impact on collaboration between MTSC partners through these activities, the impact of a 'fair' perception always generates a positive relationship atmosphere. For instance, if fairness is perceived based on the impartiality of a buyer in areas of rewards allocation, decision and process enactment, and interactive conduct, their collaborative activities with the specific buyer will improve, which can develop best practices in the relationship. The illustrative quotes from Tier-2 and Tier-1 level suppliers of a buyer (Buying Firm A and Buying Firm B) highlight this point:  We measure and review these relationships by KPIs (key performance indicators) which forms a whole part of the process such as are they delivering what they say they are going to deliver. (Tier-1 Supplier for Buying Firm A) Regular and structured meetings on project risks and different aspects of the relationship which would happen before, in-between, and after phase.
Yes, it is something we do, and we do it in different ways. So, within a project, there would be regular and structured meeting review that looks at project risks and different aspects of the relationship. So generally, we tend to put things in contract because that helps to ensure when there is a drift or shift.
(Tier-1 Supplier for Buying Firm F) Measuring relationship progress monthly and quarterly.
So, we have a number of major or substantial supply chain partners that we work with and we review those on a monthly basis face-to-face at various levels within the organisation. So, there is a meeting carried out monthly and then we go in a bit more detail in the quarterly meeting and then we go into a huge amount of detail in the six-monthly review meeting as well. (Buying Firm F) Reviewing the buyer's ability to meet values set at the start of the relationship With our big buyer, we will talk to them regularly basis about how they are meeting our values or not and conversations would be framed into that context. (Tier-1 Supplier for Buying Firm A) When we perceive fairness, we are motivated to share more information with our buyer. (Tier-2 Supplier's perspective towards Buying Firm A) Because they treat us fairly, we have now invested in technology systems like SAP to allow our key partners to have access to certain elements which would help them have a flow of information that they can use for better planning. Furthermore, we noted that collaborative activities in MTSC relationships are critical for improving specific perceptions of fairness. Distinct collaborative activities exhibited by MTSC partners can advance specific perceptions of fairness. For example, common SC activities such as information sharing, communication, and electronic data exchange can boost mutual interactional fairness since interactions require these key activities. Other collaborative activities such as dedicated investment to the MTSC were found to improve aspects of distributive fairness, as partners perceive such investments into the relationship as a fair distribution of efforts invested. Joint relationship effort was also found to improve the procedural and decision-making aspect of fairness. The illustrative quotes from a Buyer (Buying Firm B) and their Tier-1 and Tier-2 suppliers explain this point: It would impact on the additional services we would offer such as sending out our own field salespeople to assist theirs. If we feel we have a fair deal and we are being treated fairly, we will be more inclined to have more dedicated investment through our additional services. If we find that the buyer is being difficult and not wanting to share the risks, or if something happens, they are hiding it because they don't want to be seen to be creating problem, then that does have a negative effect. (Tier-2 Supplier's perspective towards Buying Firm B)

Impact of perceptions of fairness on multi-tier supply chain relationships
Our findings indicate that perceptions of fairness have an impact on factors critical to the success, sustainability and long-term development of MTSC relationships. We particularly identified relationship quality measures such as relationship commitment level, trust level, relationship satisfaction, and conflict resolution to be heavily influenced by perceptions of fairness. First and second tier level suppliers also agreed that the fairness of their buyer or manufacturers will drive the quality of their MTSC. As a result, a supplier will be willing to go the extra mile for the manufacturer and vice versa due to social responsibility and good sustainable practices throughout the network.
These perceptions of fairness serve as an enabler of sustainability throughout the MTSC through SSCM practices, which are exhibited and perceived by other multi-tier partners. Such sustainable practices which promote fairness, also reduce conflicts and tensions, and minimise the likelihood of potential issues. The following exemplary quotes from a Buyer (Buying Firm E) and their Tier-1 and Tier-2 suppliers explain how perceptions of fairness have impacted on commitment level in their MTSC relationship: For example, of one of our supply chain partners (supplier), as far as we are concerned regardless of the fact that we are in a relationship with them, they are not entirely fair to us because they don't meet deadlines, they don't meet lead times, they don't meet delivery dates and KPIs, and for these reasons we don't believe they are committed to the relationship, in fact it is very clear.

(Buying Firm E)
Yes, our perception of fairness impacts on our collaboration with our supply chain members particularly with the behavioural aspect as your attitude changes towards aspects such as effort and commitment. (Tier-1 Supplier's perspective towards Buyer E) We are more inclined to go the extra mile for someone that is treating you fairly. (Tier-2 Supplier's perspective towards for Buyer E) Perceiving fairness in the MTSC relationship also helps in developing high levels of trust which serves as an enabler for attaining sustainability from a multi-level perspective. The following exemplary quotes from a Buyer (Buying Firm F) and their Tier-1 and Tier-2 suppliers explains how perceptions of fairness have impacted on trust in their MTSC relationship: For example, if a supplier has let us down, it can be because they have handed over confidential information from their company onto a third party which wouldn't go down very well with us because some of the work that we do is highly confidential, so trust is the biggest factor that our perception of fairness would link to the most. (Buying Firm F) I know trust builds over time but when we perceive unfairness, it influences on the trust level straight away and if I had to endure due to lack of options, then I would be very careful with them. It will obviously take time and a series of unfair or fair treatments to know which direction the trust impact would lead to. (Tier-1 Supplier's perspective towards Buyer F) The first impact is having a trust level, but once you have got a level of trust, your ability to try and evaluate and understand fairness between two businesses becomes easier. (Tier-2 Supplier's perspective towards Buyer F) Furthermore, we found that perceiving fairness plays a key role in the overall satisfaction of all MTSC partners in their relationships. Considering the closed structure of the MTSC, the perception of fairness could influence behaviour and attitudes of individual firms which could in turn impact sustainability standards. The following exemplary quotes from a Buyer (Buying Firm A) and their Tier-1 and Tier-2 suppliers, explain how perceptions of fairness have impacted on their satisfaction level in their MTSC relationship: Fairness would also impact on how satisfied you are with the partner showing that you are happy with the individual firm moving forward and want to continue the relationship with them. (Buying Firm A) When they give us fair price, we tend to work more closely with them, and you have that feeling they are being fair, and they aren't ripping you off. (Tier-1 Supplier's perspective towards Buyer A) Achieving the price point you want at the detriment of the supplier would be perceived as unfair and then that affects my satisfaction level in the relationship. (Tier-2 Supplier's perspective towards Buyer A) In our analysis, we also found that perceptions of fairness decrease the prospects of potential conflicts and misunderstanding between MTSC partners. Conflict resolution is important for long-term sustainability of MTSC relationships; the following exemplary quotes from a Buyer (Buying Firm B) and their Tier-1 and Tier-2 suppliers explains this point: By treating people fairly, openly and the transparent side of things, you are actually minimising conflict and getting the best value because you can then have those open discussions about how to meet expectations, and maintain the profit margins for the suppliers but in the same instance making sure you get best value. (Buying Firm B) We have had our buyers treat us very badly in the past which resulted in a lot of arguments and conflicts regarding different disputes which we thought were unfair. (Tier-1 Supplier's perspective towards Buyer B) When our buyers exhibit fair behaviour, it reflects on minimisation of potential issues that may occur particularly with product specification because of the data they are willing to release to us. (Tier-2 Supplier's perspective towards Buyer B)

The expectations and evaluation of fairness in different stages of the MTSC relationship
Our findings reveal that the perception of fairness and the evaluation of fairness are two different things that occur during the MTSC relationship development process. The former is often formed after a series of interactions, exchanges, and relationship activities. A MTSC representative would usually perceive fairness based on the favourable behaviour and actions of their other party. This belief of being treated fairly occurs through the relationship development process based on the action of another party.
However, the latter usually occurs when important decisions are to be made regarding the status of an existing relationship at the review process (Frazier 1983), or dissolution stage (Frazier 1983;Frazier, Spekman, and O'Neal 1988). This exercise may occur as a result of a possibility of withdrawal, disengagement, or discontinuing the existing MTSC relationship based on a number of factors; these include better prices offered by similar providers, service level quality, level of expertise, potential risks, and varying levels of expectation. Thus, there is usually an appraisal of gains and losses from the MTSC relationship and a comparison with invested time, money, efforts, and resources.
Our findings highlight that this appraisal often involves the use of key performance indicators (KPI's) to determine whether a member of the MTSC is delivering what was anticipated. In line with the relationship framework developed by Frazier (1983), our findings indicate that the evaluation/manifestation of fairness usually occurs throughout the development process. However, great emphasis was made on this evaluation taking place at the review stage of the MTSC relationship where individual firms compare their rewards with their inputs. The following exemplary quotes from a Buyer (Buying Firm C) and their Tier-1 and Tier-2 suppliers explain how perceptions of fairness manifested in their MTSC relationship: Again, if you are looking at the supply chain maturity curve, you get to a certain level on that (level 3), where you've got supplier reviews in place. (Buying Firm C) We still evaluate how fairly we are being treated especially after a series of transactions . . . in fact, we as a business (and I as the boss) will not do business with people who we thought were unscrupulous which is another word for unfair. (Tier-1 Supplier's perspective towards Buyer C) In our small business, we are all involved and that way it is easier to keep a record and ensure that we are always treated fairly. If we get treated really badly, we would resolve our situation by not dealing with that person or company again, and not supply them again. (Tier-2 Supplier's perspective towards Buyer C) In our analysis, we also found that the evaluation of fairness in the MTSC relationship is a critical evaluation exercise. This process might not be useful for transactional and arms-length relationships, where multi-tier SC partners transact with no core relational framework. At the review stage, an individual firm in the MTSC might decide to terminate a relationship, if they perceive that their losses are higher than their expected rewards based on their perception of fairness.
The findings highlight that even though the three dimensions of fairness are significant for MTSC partners, they are all different in their level of significance, and individual firms often have different expectations in the MTSC relationship. For instance, individual firms regularly require information to be conveyed for different aspects of the relationship especially on how and why certain decisions, procedures, or standards have been put in place, or why apportionments have been allocated in a particular approach (Greenberg and Cropanzano 1993). These different levels of expectations are also a result of the loose coupled system (Orton and Weick 1990;Beekun and Glick 2001) of MTSCs where firms are independent, but they are still dependent on each other for sharing resources and work closely to undertake functions of the MTSC. Thus, what is important to a buyer may be different from that of their Tier-1 and Tier-2 suppliers. This may often lead to a disagreement or disparity of fairness perceptions as individual parties may operate with different goals, and varying circumstances (Luo 2005). The following exemplary quotes from a Buyer (Buying Firm C) and their Tier-1 and Tier-2 suppliers shows their expectations: Critically you've got to be able to trust your supplier. So, they have got to be honest and open as much as commercially available and they have got to demonstrate integrity around what they promised and what they deliver. (Buying Firm C) When dealing with our buyer, one of the essential things in terms of fairness is ensuring that we are given an opportunity to present our best price or best product or best service level agreement, ensuring that we are given equal opportunity to put that across and we are treated and evaluated in the exact same way. (Tier-1 Supplier's perspective towards Buying Firm C) Information sharing is the most important collaboration activity or practice, building a good rapport and having a good connection and getting to know your supply partners. (Tier-2 Supplier's perspective towards Buying Firm C) Our findings show that these different expectations are an important consideration for the management of MTSC relationships, particularly towards attaining social sustainability goals and longevity. Different expectations will often lead to different behaviour which influence the demonstration of fairness in the MTSC relationship.
All dimensions of fairness were revealed to be essential in the relationship building process. However, the interactional and distributive dimensions were mentioned repeatedly as vital for the MTSC. This is not surprising considering that SET already stresses the social and economic nature of such inter-firm relations (Emerson 1976;Lind and Tyler 1988). The following exemplary quotes from a Buyer (Buying Firm D) and their Tier-1 and Tier-2 suppliers explain their expectations: We use three words that I think outline how we treat people and they are honesty, decency and integrity. (Buying Firm D) We want to get the best price and deals at all time, and we avoid getting ripped off or being cheated by another firm. (Tier-1 Supplier's perspective towards Buying D) It would be very much around making sure that our payments and benefits were paid from time to time. (Tier-2 Supplier's perspective towards Buying D)

Theoretical implications
This research offers valuable contributions to theory by extending the debate on the role of fairness in SC relationships in a multi-tier context. This new perspective has been omitted by past studies (e.g. Griffith, Harvey, and Lusch 2006;Liu et al. 2012;Narasimhan, Narayanan, and Srinivasan 2013;Huo, Wang, and Tian 2016;Matopoulos et al. 2019), as the focus on fairness has wholly been on the single or dyadic unit of analysis (Bouazzaoui et al. 2020). With the help of the SET (Emerson 1976), this research contributes new insights to the SC literature by proposing a detailed framework which reveals how perceptions of fairness impact the relationship between MTSC partners, and how fairness perceptions are manifested in different stages of the MTSC relationship development process.
The findings of our research recognise the significance of perceptions of fairness as a driver of collaboration between MTSC partners. Literature has stressed the importance of collaborative activities as a crucial factor for supplier efficiency, attracting more like-minded suppliers, decreasing costs, and minimising potential risks (Wiengarten et al. 2010;Cao and Zhang 2011;Villena and Gioia 2020). However, our study reveals that the perceptions of fairness can improve collaborative activities between MTSC partners (e.g. information sharing, joint relationship effort, dedicated investments), which can lead to fair outcomes (e.g. distributive, procedural, interactional), and improve social sustainability performance. Likewise, our study also identified that each dimension of fairness has its own unique determinant (Luo 2007). For example, when a MTSC partner perceives interactional fairness which relates to social aspect of fairness, they are more likely to reciprocate by exhibiting high levels of communication and information sharing. Likewise, when a MTSC partner perceives distributive and procedural fairness, they are motivated to invest more effort and resources into the relationship. Figure 1 illustrates the impact of fairness perceptions on collaborative activities between MTSC partners.
In line with existing literature (e.g. Trada and Goyal 2017;Blessley et al. 2018) and the SET perspective (Emerson 1976), our findings highlight the significance of the perceptions of fairness for building longlasting sustainable MTSC relationships. Firms are coming under increasing pressure to develop close relationships towards a supply chain versus supply chain competition, in contrast to the traditional firm versus firm competition (Schmitz, Schweiger, and Daft 2016). Thus, our study reveals how perceptions of fairness can improve the strength of MTSC relationships through the level of relationship quality (commitment, trust, satisfaction, and conflict resolution) between partners, which can, in turn, minimise sustainability tensions from economic, structural, behavioural, and psychological differences (Fang, Chang, and Peng 2011;Tura, Keränen, and Patala 2019). As this study is one of the first to examine the notion of fairness beyond the single or dyadic perspective, we were able to add valuable insights on a SC level and possibly network level, regarding how fairness perceptions can impact relationship development, longevity, and the intention for future collaboration. Based on the SET perspective, these insights also contribute to the discourse relating to the social aspects of SSCM (e.g. Bai et al. 2019; Orji, Kusi-Sarpong, and Gupta 2019; Kusi-Sarpong, Gupta, and Sarkis 2019; Govindan, Shaw, and Majumdar 2020; Alghababsheh and Gallear 2020), with a focus on the social behaviour of SC partners. Figure 2 depicts the impact of fairness perceptions on the relationship development between MTSC partners.
Finally, the relationship development process between buyers and suppliers is viewed as a process where firms go through different phases (initiation, implementation, and review) (Frazier 1983;Frazier, Spekman, and O'Neal 1988). Usually, SC partners will compare their gains (losses) to their contributions and they will compare those subsequent percentages to other firms. Each phase represents a transition with regards to how SC partners view each other, how they test each other through exercising purchasing and bargaining power, and the subsequent formation of fairness perception (Dwyer, Schurr, and Oh 1987). However, most studies conducted on fairness in the SC context have rarely explored the dynamics of on-going fairness formations in the different phases of the SC relationship development process (Liu et al. 2012). This study explored this issue by revealing how perceptions of fairness are manifested in the different stages of the MTSC relationship development process. Specifically, the results of this study indicate that perceptions of fairness are most crucial at the review phase of the relationship development process, where MTSC partners evaluate their rewards and losses, and compare them with their expectations, based on efforts invested in past exchanges and interactions. Figure 3 depicts the manifestations of fairness perceptions in the MTSC relationship development process.

Managerial implications
Understanding the drivers of sustainability standards is an important issue for all exchange parties, especially for firms participating in strategic long-term relationships. The findings of this study offer valuable practical contributions. First, mutual fairness perceptions can significantly drive MTSCs towards positive relationship outcomes. Our study reveals that when all parties in the MTSC relationship (i.e. buyer, tier-1 supplier, and tier-2 supplier) perceive high levels of fairness simultaneously, there would be a higher level of collaboration through shared information, joint relationship effort, and dedicated investment between them. Thus, SC practitioners are encouraged to regularly exhibit the three dimensions of fairness (distributive, procedural, and interactional) throughout the different stages of the vibrant relationship development process (initiation process, implementation process, and review process). Second, although fairness perceptions play a significant role in driving collaboration, they also have a critical role in developing MTSC relationships, especially from a long-term perspective. SC firms enter into relationships based on the notion of value and the expectation to receive fair distribution of resources and outcomes (Griffith, Harvey, and Lusch 2006;Zaefarian et al. 2016). Likewise, boundary spanners (relationship managers) will be committed to relationships that encourage politeness, dignity, respect, mutual respect, and interpersonal communication. Our findings show that under such circumstances, common perceptions of fairness will improve relationship quality measures such as higher levels of trust, commitment to the relationship, and the overall level of satisfaction in the MTSC relationship. These activities will also improve the prospects for relationship development with individual SC firms. Therefore, SC practitioners are encouraged to include the idea of fairness in their relationship development agenda. Managers in buying firms in developed countries should invest in training and developing their firm representatives about the benefits of fair practices and reciprocity in the SC context. They may also include the fairness agenda (distributive, procedural, and interactional) in trading handbooks and terms of trade, structured meetings, educational programmes, workshops and seminars, and supplier development initiatives, especially for multi-tier suppliers in emerging markets. This may help practitioners address concerns related to the negative use of power by more influential parties, the exhibition of opportunistic behaviour, and unethical trading practices.
Third, the results of this study will help SC practitioners understand the dynamics of on-going formations of fairness in different phases of the relationship development cycle. Specifically, a comprehensive framework is presented which gives a step-by-step illustration on how fairness perceptions are manifested, from the initiation phase to the review phase of the relationship development process. At the initial phase of the MTSC relationship, practitioners are encouraged to invest sensibly towards knowing their first-tier and second-tier suppliers well enough to manage expectations from all parties. Afterwards, a hands-on approach is required to manage the perceptions of fairness up until the review and evaluation phase of the relationship, especially by the more powerful party in the MTSC.

Conclusion
With the help of the SET, this research has examined the notion of fairness in MTSC relationships, focusing on the relationship between MTSC partners in the U.K. and India. The concept of fairness has started to gain increasing interest in the SC literature from different angles. Some studies have focused on its dimensions of fairness, while others have considered its relationship with performance. The consensus from past studies is that fairness has the potential to improve or damage SC relationships. However, past studies have rarely considered the MTSC context in the examination of fairness, which this study addresses through two questions. The first research question examines how perceptions of fairness impact the relationship between MTSC partners. The second question considers how perceptions of fairness are manifested in different stages of the MTSC relationship. This research reveals that fairness is an antecedent of collaboration between MTSC partners. It demonstrates that when fairness is perceived by MTSC partners, it has positive implications for their existing collaboration (by encouraging collaborative activities such as information sharing, joint relationship effort, and dedicated investment). Likewise, these perceptions also impact the quality of the relationship between MTSC partners (through trust, commitment, satisfaction levels), and long-term relationship development (through future collaboration intention and relationship longevity). The findings also show how perceptions of fairness are manifested in the different stages of the relationship development process between MTSC partners. It showed that the review stage was the key phase where crucial decisions are made by individual firms based on their past exchanges and experiences in the relationship.

Future research direction
Although this study has made new contributions, there are some limitations which offer useful and additional opportunities for further research into this topic. This research has used the SET to improve our understanding of fairness perceptions in the context of MTSC relationship. Future studies may consider adopting other theoretical perspectives such as equity theory (ET) (Adams 1963(Adams , 1965Kabanoff 1991), behavioural theory (Payne, Bettman, and Johnson 1993), network theory (Granovetter 1992) to uncover some of the hiding benefits of exhibiting fair practices in the relationship between MTSC partners. In particular, theoretical perspectives such as the loose coupling theory (LCT), which considers supply chains as loosely coupled systems (e.g. see, Weick, 1976;Orton and Weick 1990;Beekun and Glick 2001;Liu et al. 2012), could be adopted by future studies to improve our understanding of the individual roles that MTSC partners play towards achieving fairness and reducing opportunism from a loose coupling logic.
This research has presented interesting results based on data obtained from U.K. manufacturers and their firsttier and second-tier suppliers in India. Seeking external generalisation was not the aim of our study; thus, future studies can conduct similar research involving data collection from other contexts such as MTSC relationships emerging and developing countries to enhance the generalisability of our findings. Our research was exploratory in nature, and we were only able to use interviews for deeper knowledge. To be able to fully explore and capture a full representation of the influence of fairness perceptions in the MTSC setting, we suggest, for future research, increasing the sample size and broadening the geographic location to obtain more comprehensive data. Due to the complexities linked with developing and emerging markets (Oyedijo, Adams, and Koukpaki 2021a;Oyedijo et al. 2021b), to improve our current understanding, future studies may also consider how fairness perceptions develop and manifest in MTSCs operating in such contexts. This will bring forth interesting findings based on the unique characteristics of such locations.
To gain a deeper understanding of fairness in MTSC relationships, future studies may also include new constructs linked to the social sides of SC relationships in our comprehensive framework. We considered some dimensions of relationship quality in this study. However, by no means do we claim that there are only three relationship quality measures in the MTSC context. Thus, future studies may include other higher order relationship quality variables such as opportunism (Dorsch, Swanson, and Kelley 1998;Tran, Gorton, and Lemke 2021), conflict resolution (Kumar, Scheer, and Steenkamp 1995), loyalty (Rauyruen and Miller 2007) as an extension of our conceptual framework. Likewise, other dimensions of SC collaborative responses (Simatupang and Sridharan 2005;Cao and Zhang 2011;Soosay and Hyland 2015) can be added to examine how perceptions of fairness can influence the development of a long-term relationship between MTSC partners, particularly towards achieving sustainability. Finally, this research has established that perceptions of fairness can influence MTSC relationships. However, a productive future research avenue would be to examine antecedents of fairness in the MTSC relationship context, namely the unique factors that influence how fairness is exhibited in the relationship between MTSC partners (e.g. see, Luo 2007). This perspective would offer a deeper level of understanding of the concept of fairness in the MTSC relationship context.

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