Evaluating Sustainable Purchasing Processes in the Hotel Industry

Abstract

Managing sustainability along the supply chain has gained significant relevance in recent years, in both academic and business environments. The aim of this research paper is to describe and evaluate the degree of implementation of sustainable purchasing (SP) in the supply chain of the hotel sector in Spain, as well as to identify the main drivers and barriers to effective implementation. This is done from the double perspective of hotel chains and suppliers (industrial laundries). An exploratory and inductive qualitative methodology has been adopted, consisting of (a) observation; (b) collection, review, and analysis of primary sources; and (c) in-depth interviews with 15 managers of hotel chains and suppliers. This triangulation of data sources provides validity and credibility to the results and reduces any potential bias. Evidence is found to support that SP is at an early stage of implementation in the hotel sector in Spain, with big differences among companies. The results suggest that the main drivers and barriers to effective implementation are final customers, governments, market conditions, management commitment, and conflicts in customer/supplier interests. The authors propose a new classification of companies based on the size, type, and degree of implementation of SP.

1. Introduction

The concept of sustainability has gained great relevance in recent years, in both academic and business environments. The World Commission on Environment and Development [1] (p. 8) defined sustainability as “development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” Sustainability management implies that companies should consider the impact of their actions not only on economic aspects, but also on environmental and social ones [2]. All stakeholders (clients, governments, organizations, workers, communities, suppliers, etc.) are increasingly exerting pressure on companies to put in place policies that ensure compliance with sustainability objectives from these three perspectives. Having good or bad performance in these aspects has a very significant impact on the image of the company and might bring relevant consequences.

However, compliance with sustainability criteria should not be considered solely within the company itself, but must go beyond its boundaries, throughout the entire supply chain in which it operates. It is not enough for a company to comply within social and environmental fields; its suppliers must also comply with it, since if the management of its suppliers is not adequate, the company’s reputation might be damaged to a large extent, and its level of performance might also be impacted [3,4]. In recent years there have been cases in which this has occurred with companies such as Mattel, Nike, and Dell [5,6,7,8].

Therefore, it is the responsibility of companies to ensure that they manage their supply chain in a sustainable way. Despite the fact that sustainability is increasingly emerging in companies’ supply chain practices, especially in multinational enterprises [9,10,11,12], corporate initiatives to implement sustainable purchasing (SP) are still scarce, disordered, and not well anchored on strong motivations to exert sustainable behaviors and to disclose trustworthy and accurate information about them [13,14]. Moreover, the extent of deployment and integration of these policies differs significantly depending on the business sector and the type of company [15]. Stakeholders increasingly have higher expectations for companies to adopt effective SP policies towards all suppliers with whom they work [16]. There is still a great distance between the society and community expectations and reality, and this occurs both in private and public corporations [10].

Sustainability in supply chain management (SSCM) has not been addressed in a holistic and comprehensive way. First, attention has been paid mainly to environmental issues, leaving wide room to attempts aimed at understanding the social side of supply chain sustainability [16,17,18]. Second, most studies adopt an instrumental—“what-do-I-earn-if-I-act-sustainable”—approach limiting the understanding of SSCM to cause-effect and reactive-to-compliance understandings [16,19,20]. And third, research has focused mainly on the sustainability of downstream supply chain; consequently, upstream sustainable practices remain insufficiently addressed [19,21,22].

Thus, there is a need to strengthen and reorient research on SCM sustainability [16,23,24,25,26], and in particular, the purchasing function, which has a greater environmental bias [10,25,27,28,29]. In part, this bias is due to the different emphasis required by the environmental dimension, focused on the product and all stages of its life, and the social dimension, with greater emphasis on the supplier and the conditions around the production process [10,25].

Top management appears to be one of the most relevant drivers of the implementation of the purchasing function, so it is necessary to better and more thoroughly define the exact role to be played by top management. On the one hand, managers might send a clear message of responsibility to the organization and thus motivate responsible purchasing practices. According to Espino-Rodríguez [30], “the application of operations policies and practices has a short-term effect on non-financial performance, measured as the satisfaction of stakeholders (customers, tour operators, and employees), and a possible long-term effect on financial performance (e.g., return on assets, profit margins, occupancy)” in the hotel industry in Spain. On the other hand, managers might not authorize expenditures for, or investment in, responsible purchases, thus saving funds for future projects. As research has found that cost is the main barrier, these behaviors can simply be a sign of the low priority given to the role of responsible purchasing by senior management [4].

This is also applicable to the tourism sector in Spain, and more specifically to the hotel industry, one of the sectors with a high impact on the country’s economy, whose companies, as in any other industry, are called to be responsible. When assessing the way in which they address sustainability, we can see that the situation is less developed than that of other sectors: There is some activity from both the academic and business practice points of view, with the aim of implementing sustainability aspects and policies in large companies in the sector. However, most of them focus more on the environmental aspect (new designs of facilities, energy efficiency, and waste management, primarily). There are some non-academic publications and editions of documents issued by companies, sectoral associations, consultancies, or other groups of interest. Examples of this type of document could be their codes of conduct, annual company reports, or sustainability reports, and specific initiatives that lead to recognition awards by the sector, etc. In the last sectoral meetings, several initiatives were presented and seminars were developed to raise awareness of the need to address the concept of sustainability as a strategic pillar. These initiatives are led by some companies, associations, the administration, and specific organizations, and in general they are more oriented toward environmental aspects. Examples of this type of document could be national tourism plans, those derived from programs and sessions at international fairs such as FITUR (Feria Internacional de Turismo, Madrid, Spain), or initiatives by the World Tourism Organization.

Regarding the responsible management of the supply chain in this sector and, particularly, incorporating sustainability within the purchasing function, it is noted that activities and literature are scarce and in their earliest stages, from both the academic and non-academic point of view.

The objective of this research paper is to describe and evaluate the degree of implementation of SP in the supply chain of the hotel sector in Spain. This is done from the double perspectives of customers (hotel chains) and suppliers (industrial laundries). More specifically, the purpose of this paper is threefold: First, to evaluate how companies in this sector follow the proposed models and frameworks from the literature; second, to identify the main drivers and barriers to effective implementation; and third, to determine whether a taxonomy of companies with different purchasing categories can be proposed based on previous findings.

An exploratory and inductive qualitative methodology was followed, consisting of (a) observation; (b) collection, review, and analysis of primary sources; and (c) in-depth interviews. In-depth interviews were conducted with 15 managers of client and supplier companies (hotel chains and industrial laundries), providing the authors with a reliable view of what is happening in this sector. The information obtained through observation and primary sources was completed, confirmed, and consolidated. This triangulation of data sources provided validity and credibility to the results and reduced any potential bias.

Evidence has been found to support that SP is at an early stage of implementation in the hotel sector in Spain, with big differences among companies. The results suggest that the main drivers of, and barriers to, effective implementation are final customers, governments, market conditions, management commitment, and conflicts in customer/supplier interests. The same factors may act as drivers or enablers when they help or support effective implementation, or as barriers when they hinder it or make it difficult. The authors propose a new classification of companies based on the size and type of corporation and degree of implementation of SP. This study also proposes an implementation model, as well as a list of initiatives and proposals for industry managers and policy makers.

The paper has been organized as follows: Section 1 is the introduction; Section 2 refers to the literature review; Section 3 describes the methodology and materials; Section 4 presents the results; Section 5 is the discussion.

2. Literature Review

One of the main research concerns in tourism has been customers’ sensitivity toward sustainability as a development driver of the industry [31,32,33,34,35,36]. However, many studies have revealed that the industry is reacting slowly to this need despite the growing global relevance of sustainability in business [37,38,39]. Explanations for this can be found in a “lack of collective leadership amongst tourism’s stakeholders” and in the so-called environmental paradox of the industry: Whereas natural resources are key characteristics of tourist destinations, such resources are at the same time sacrificed to satisfy a growing demand [39].

The large amount of studies published on sustainability in the hotel industry reveals a wide variety of approaches and matters of research in this field [40]. Previous works have mainly addressed the design of more ecological and efficient hotels, the reduction of water and energy consumption, technological innovations to improve sustainability, and progress in workforce management. Consumers’ satisfaction with hotels’ sustainable practices is another concern that has received much attention [41,42,43,44,45,46].

Other works have addressed the role of management systems for sustainability [47] and, particularly, the aspect related to “reporting practices” [48,49]. De Grosbois [50] analyzed the methods and scope of corporate social responsibility (CSR), reporting on 150 of the world’s leading hotel chains. He pointed out that, although many of them reported their commitment to and objectives for aspects of environmental and social sustainability, few detailed specific initiatives were developed or results achieved. Regarding environmental practices, reporting on EMS—i.e., corporate policies, assessments, plans, and actions directed to define the company relationship with the natural environment—has gained significant weight in the promotion of more sustainable supply chain practices since it can lead to gain international accreditation of best practices. Such accreditation is granted if EMSs actually comply with the International Organization for Standardization (ISO) 14,001 and 14,040 standards, or with the European Eco Management and Audit Scheme (EMAS) standard [11,51,52]. Research has shown that, compared to manufacturing companies, service ones—such as hotels—are more confident in the benefits of having environmentally accredited supply chain practices [11].

Looking specifically at the case of the Spanish hotel industry, the work of Molina-Azorín et al. [53] offers an empirical analysis of the impact of sustainability practices on firm performance, highlighting how the environmental management of hotels can reduce their costs and increase their returns. In this sense, on the one hand, they identify, through regression analysis, those practices with the greatest impact on a series of variables related to performance. On the other hand, through a cluster analysis, they identify three groups of hotels (proactive, basic, and reactive) based on their proactivity in environmental management practices, showing significant differences in performance between them. “Environmentally proactive” refers to hotels with the most developed environmental strategies, including higher-category hotels usually affiliated with a hotel chain. The second group, basic, includes hotels with a basic environmental commitment. It is the largest group, and is characterized by its three-star, independent, above-average sized hotels. The third group, reactive hotels, have a low environmental commitment, usually three-star, independent, small hotels. Eco-labels are strong indicators of the environmental practices of companies, they help build an image in consumers’ minds and to prevent confusion about the actual company environmental behavior [54]. In the hotel industry, the European eco-label requires the compliance with a number of provisions and conditions, some of them referring particularly to holding a green supply chain: The use of eco-labelled products in their service supply; integrated environmental values in the operations management, and initiatives for reducing the use of energy and the creation of waste. Like environmental regulatory standards, the use of eco-labels promotes environmental practices since they are perceived by hotels to be accompanied by economic benefits, competitive and commercial [55].

Rodriguez-Anton et al. [47] analyzed the use of sustainability management systems in the Spanish hotel industry, looking empirically at their existence as well as their scope, sequence of implementation, and possible integration of different standard management systems.

Despite some notable efforts to crystallize and systematize conceptual frameworks for sustainability in the hotel sector (first by Clarke [56], and recent studies [38,40,57,58]), this apparent richness and dynamism that characterizes the academic literature includes weaknesses, such as a fragmentary nature and the lack of a coherent structure or clear framework of analysis, and the need for consensus on priorities for future research agendas [40], the identification of more consistent methodological approaches, and the development of appropriate measurement scales [58].

On the other hand, in relation to the hotel sector, more scholars have pointed out that academic research should integrate the three aspects of sustainability (economic, social, and environmental) with a holistic approach [3,50], in addition to developing a deeper understanding of sustainability specifically related to SCM [59,60,61,62,63]. In this sense, it is worth highlighting the work of Zhang et al. [64], who present a review of the literature related to SCM in the context of tourism, as well as the work of Xu and Gursoy [65], who present a conceptual framework for sustainable hospitality SCM and start a discussion about the impact on customers’ satisfaction, loyalty, and willingness to pay extra. They present “five critical aspects including the actions, motivators and inhibitors, company characteristics, the evaluation approaches, and the impacts.” Sustainable hospitality SCM can be defined as “the management of material, products, services, and cooperation and coordination among organizations in the hospitality supply chain to achieve three objectives of sustainable development: environmental, social, and economic sustainability” [65].

Carter and Jennings [66] proposed a new concept, purchasing social responsibility, along with its specific activities and drivers, developed through a review of the CSR and related purchasing and SCM literature and an integration of extant findings from in-depth interviews with supply chain managers. Hollos et al. [67] examined the effects of sustainable supplier cooperation on firm performance. Through an empirical study based on a survey in Western European countries, they conclude that sustainable supplier cooperation has generally positive effects on firm performance across the three dimensions of sustainability. However, only environmentally friendly practices have positive and significant effects on economic performance.

In this same direction, but with empirical research specifically focused on the European hotel industry, Kassinis et al. [68] explored, through a structural equation model, the nature of the relationship between environmental management practices on the “external portion of the service profit chain” and performance. Particularly, they show that the use of environmental practices in service companies is positively related to performance through the mediating effect of greater consumer satisfaction and loyalty.

The literature includes some efforts to offer a frame of general validity for managers on the dimensions and motivational factors of responsible supply [66], or for the understanding of trans-sectoral models of sustainable SCM, and propose schemes of general application [25,69,70,71,72]. These frameworks or models can be of a different nature, depending on whether they: (i) Refer globally to sustainable SCM or focus more on the purchasing function; (ii) can refer to a specific aspect within this function or to the implementation process; or (iii) identify the factors that influence an adequate implementation or not. However, each author identifies different stages and key success factors for an adequate SP implementation process. Mamic [23], for example, indicates that the common elements of these integrated models generally cover the following four areas: (a) Development of a vision; (b) understanding of that vision by employees and suppliers; (c) implementation; and (d) monitoring, feedback, and improvements.

In addition, none is conceived or presented as a decision model for the company that allows weighing advantages and disadvantages of alternatives or their adaptation to different business contexts and strategies. Nor is there a model that combines stages with obstacles to, and drivers of, each stage or that describes the influence of different stakeholders in each stage. However, Maloni and Brown [5] consider that each sector or industry has sufficiently significant peculiarities to require the development of independent sector studies that adapt the risks, priorities, and management models specific to each industry. Additionally, we find that the literature has scarcely examined the relationship of SP with the size of the company: Fassin [73] warns that studies tend to focus on the relationship between transnational corporations and their suppliers in less developed countries; thus, these studies pay little attention to the role and particularities of small and medium enterprises.

The literature related to different models or theoretical frameworks on SP implementation processes has been reviewed [3,7,23,25,27,28,29,66,67,69,70,71,72,74,75,76,77,78,79,80,81,82,83,84,85,86]. A summary of the findings is presented in

Table 1. Summary of sustainable purchasing (SP) implementation models from the literature.

Authors	Date	Description	1	2	3	4	5	6
Carter and Jennings	2004	Purchasing role in CSR	P		✔
Mamic	2005	Global SCM	SCM		✔	✔		S
Teuscher et al.	2006	Framework for sustainability in SCM	SCM		✔
Vermeulen and Ras	2006	The Challenge of Greening Global Product Chains: Meeting Both Ends	SCM		✔			S, G
Svensson	2007	Conceptual framework and empirical example	SCM		✔			S
Carter and Rogers	2008	Framework for sustainability in SCM	SCM		✔
Seuring and Müller	2008	Theoretical framework for sustainability in SCM	SCM		✔
Vurro et al.	2009	Model classification according to network determinants	SCM
Björklund	2010	Benchmark tool for CSR in purchasing	P	✔	✔		✔	G
Hietbrink et al.	2010	CSR in purchasing function	P		✔
Leire and Mont	2010	Implementation model for socially responsible purchasing	P	✔	✔		✔	G
Dai and Blackhurst	2012	Four-phase AHP-QFD approach for supplier assessment	P		✔	✔	✔
Wolf	2011	Integration of sustainable SCM in German manufacturing industry	SCM		✔	✔		S, G
Giménez and Tachizawa	2012	Extending sustainability to suppliers	SCM		✔	✔
Perry and Towers	2013	Conceptual framework for implementation of SCM	SCM		✔	✔		S, G
Vargas and Moreno	2013	Efficient and SP management	P		✔			G
Azadnia et al.	2015	Sustainable supplier selection and order lot-sizing	P		✔	✔	✔
Atkin and Gergin	2016	Mathematical modeling of sustainable procurement strategies	P		✔	✔	✔
Prier et al.	2016	Practices on sustainable public purchases	P		✔	✔		S
Carbone et al	2012	Diffusion of sustainable SCM toward a conceptual framework	SCM		✔
Hollos et al.	2012	Examining whether sustainable supplier cooperation affects performance	P		✔			G
Kirce and Seifert	2015	Dynamic capabilities in sustainable SCM theoretical framework	SCM		✔			S
Ahmad et al.	2017	Integrative framework for sustainable SCM practices in the oil and gas industry	SCM	✔	✔			S
Tavana et al.	2017	Hybrid goal programming and dynamic data envelopment framework	SCM			✔	✔	S, G
Abduh et al.	2018	Development methodology for sustainable procurement of construction works in Indonesia	SCM		✔			S, G
Prasad et al.	2018	Analyzing the critical success factors for implementation of sustainable SCM: Indian case study	SCM		✔			S, G

Notes: 1. Scope: Purchasing function (P), supply chain management (SCM); 2. Real implementation model, with all stages clearly identified and described; 3. Identifies factors (drivers and barriers) for implementation; 4. Just focused on one stage (e.g., supplier assessment or implementation of code of conduct); 5. Decision tool; 6. Specific sector (S), or geographic area (G).

, with details about (1) scope (P for purchasing function, SCM for supply chain management); (2) whether it is a real implementation model, with all stages clearly identified and described; (3) whether it identifies factors (drivers and barriers) for implementation; (4) whether it is just focused on one stage (e.g., supplier assessment or implementation of code of conduct); (5) whether it is a decision tool; and (6) whether it refers to a specific sector (S) or a geographic area (G).

We note that most of the proposed models refer to sustainable SCM generically, without going into detail on the topic of purchasing management, which is the subject of this study. Likewise, the vast majority of the models try to define a general framework, in which proposals are made on the level of interrelationships of various stakeholders and actors in the supply chain and relationship strategies between them. Only two studies [25,76] tried to develop an SP implementation model in which each and every one of the stages for the complete implementation process is presented in a clear and detailed manner, identifying the key decisions of each stage and the success factors. The other models provide very interesting ideas and proposals, and a framework for carrying them out, but they do not take these ideas to all stages of the buying process. Some models refer to the purchasing function, but they focus on a very specific aspect or phase within the SP process. For instance, one model focuses on the development and implementation of codes of conduct; another mathematical model proposes measurement to assess the degree of sustainability of suppliers (so they serve as a tool for decision making on supplier selection). Some refer to specific sectors (manufacturing, textiles, food, footwear, public administration, etc.), or to certain geographical areas in which companies operate (Asia, South Africa, Germany, United States, Colombia, etc.).

Of all the references studied, Leire and Mont [25] propose the most complete model of implementation of the SP function, based on secondary and empirical sources, including interviews with different organizations, which allowed them to validate their conclusions. We chose this model as a basis for our study because it responds more directly to the set of objectives, with a clear focus on the practical implementation of sustainability in purchasing, describing each stage and phase, identifying the responsibilities in these stages and the factors that influence them for adequate implementation. The model is presented as a tool that can help in decision making and is applicable to any sector. The rest of the studied references are not discarded, but they provide good inputs, ideas, and proposals that complement the use of this model. These contributions were used in the preparation of the interview script.

The model of Leire and Mont [25] of implementation of the SP function is based on a process consisting of five stages: (i) Developing internal policies; (ii) setting purchasing criteria; (iii) applying assurance practices; (iv) managing supplier relations; and (v) building internal SP capacity. This model details all the phases in the SP implementation process and how they are connected to each other. It begins with developing internal policies within the organization itself. From there, purchasing criteria are established, particularly the sustainability criteria that must be incorporated in the purchasing process. This is the starting point for the selection of suppliers and the application of control practices and monitoring of suppliers. The relationships with suppliers should not be based solely on monitoring and controlling certain performance indicators; it is essential to take into account other aspects in the management of the relationship. Finally, the model proposes the development of internal capacity for SP management.

Most of the frameworks or models discussed above make good proposals regarding the factors that most influence adequate SP implementation, identifying the drivers that favour its implementation as well as the obstacles or barriers that make it difficult [3,7,10,23,25,27,28,29,46,66,67,69,70,71,72,74,76,77,78,79,80,81,82,83,85,86]. Drivers are classified as internal factors (within the buying company) or external factors (outside the buying company). In the same manner, barriers are classified as internal barriers (within the buying company) or two kinds of external barriers (outside the buying company, and for suppliers).

Table 2. Drivers of SP implementation.

References	Drivers of Implementation
[3,7,10,23,25,27,28,29,46,66,67,69,71,72,76,77,79,82,83,85,86]	Internal factors within the buying company Risk mitigation, and therefore cost reduction. Vision of the organization, policy, or code of conduct. A leader in the organization who launched SP initiatives. Protection of the brand image. Search for suppliers that share the same values as the organization. Providing workers with an adequate environment. Feeling of pride by company workers thanks to its values and practices. Individual values of purchasing department employees. For public organizations: Preserving the good name of the region or country. For suppliers: Working on social issues can expand the customer base. Size and organizational culture of the company.
[3,10,23,25,29,46,66,69,71,72,76,77,78,79,80,81,82,83,85,86]	External factors outside the buying company Expectations of stakeholders, especially nongovernmental organizations (NGOs) and media. Public opinion. Compliance with regulations by the government and public administrations. Maintaining legitimacy in the eyes of stakeholders. Market and final consumers require more good records on SP practices. External evaluations and ratios. Participation in the development of standards on social issues. Need to report sustainability issues. For public organizations: Political vision in the region or country. For public organizations: Decisions of politicians. Generalized practices in the sector and between competitors. Differentiating element with respect to the competition. Involvement of third parties that support the implementation process.

and

Table 3. Barriers to SP implementation.

References	Barriers of Implementation
[3,7,10,23,25,66,67,72,74,76,79,80]	Internal barriers for the buying company Lack of information on how to develop or implement SP policies. Lack of commitment from senior management, especially in the implementation phases. Need to justify the activity and its cost based on the benefits it brings to the company. Significant changes in the buying organization may be required. Lack of material and resources for staff training due to the specificity of sector/company. Organizational inertia. Conflict with short- and long-term interests.
[3,10,23,25,28,72,74,76,79,83]	External barriers for the buying company High cost of supplier audits. Qualification of audit teams: Low-quality risk due to growing competition between audit firms and low prices. Difficulty in establishing cooperative and long-term relationships with suppliers. Lack of understanding of the importance of social aspects by suppliers, as well as duplicity of “accounting books” and deception. Difficulty in influencing beyond level 1 of suppliers and high cost of changing suppliers; complex supply chains, with several levels of subcontracting that are difficult to control. Employees of suppliers could support current practices (for instance, excessive overtime). Lack of clear legislation for clients on how to integrate social aspects into the supply chain. Operations of suppliers with a low level of automation (more labor-intensive operations). Continuous pressure from the competition to lower prices. Difficulty in verifying the veracity of the responses of suppliers. Difficulty in verifying the implementation of action plans carried out by suppliers. Communication and information problems in the market (to/from customers/suppliers). Institutional barriers in international trade. Doubts about the economic situation when making investments.
[3,10,25,66,69,70,72,74,76,79]	External barriers for suppliers Customer practices with urgent orders and increasingly shorter delivery times facilitate worse working conditions and lack of attention to safety issues. Requirements from different clients, increasingly numerous and sometimes contradictory. Lack of legislation and its reinforcement for suppliers in one or several countries. Conflict between high levels of performance in sustainability criteria and increasingly reduced margins in products and services. Difficulties in influencing beyond level 1 of suppliers; complex supply chains, with several levels of subcontracting that are difficult to control. Time dedicated to preparing audits and inspections. Trust in relationships.

present a summary of all of them.

3. Materials and Methods

An exploratory and inductive qualitative methodology was used, aimed at theory building. It consisted of (a) observation; (b) collection, review, and analysis of secondary sources; and (c) in-depth interviews. This approach is particularly useful when the research needs to answer “how” and “why” questions [87]. Interviews are “a highly efficient way to gather rich, empirical data, especially when the phenomenon of interest is highly episodic and infrequent” [88], as well as in circumstances when (i) there is little documentation; (ii) it is unclear and unstructured, making it difficult to compare and interpret; (iii) the information is only provided from the perspective of the client, not its suppliers; and (iv) it is difficult to contrast whether what is said in the documents corresponds to the reality of what is actually done [89]. The combination of data collection techniques provided validity and reliability to the results and helped to reduce any potential bias.

Observations were based on documented experiences by one of the authors during close to two years working in this industry. Observation and analysis of secondary sources (documents from company websites, industry reports, congress, etc.) showed that information about sustainable business practices is incomplete, scarce, unclear, and hardly comparable. Sustainability issues are delicate and sensitive, so formal business documents tend to avoid being specific about the company position, initiatives, commitments, and/or future plans. The in-depth interview is a methodology that helps to collect precise and detailed qualitative information and is used when the research problem cannot be completely observed due to ethical or complex issues [90]. We conducted individual in-depth interviews with interlocutors from hotel chains and their suppliers. We then carried out an in-depth category and interpretative analysis of our interviewees’ responses.

First, an interview script (see a script summary in Appendix A) based on the literature review was prepared, but issues were reformulated in a language suitable for our interlocutors to understand. The script begins with an introduction to the research project and some general questions about the business context of the company, and then deepens into questions about the implementation of SP policies. The questions are fundamentally based on concepts extracted from the model of Leire and Mont [25], although they also use as reference the rest of the models described in Table 1 in the previous section. Some of the questions were formulated in a very precise way, looking for a concrete answer, and some were done in a more open way in order to encourage the interlocutor to respond more freely. Depending on the interview, new questions could arise to clarify and specify some of the answers.

When determining the number of people to interview, the principle of theoretical saturation was taken into account, which says that the so-called theoretical saturation point is reached when the information collected is enough in relation to the research objectives [91]. For a population under study that is homogeneous, made up of experts in the field of study, and the objectives are well defined, Guest et al. [92] suggest that a sample of 6 interviews is enough to achieve information saturation. A sample of 7 client-type companies (hotel chains) and 6 supplier-type companies (industrial laundries) was determined, for 13 companies in total, but there were 15 interviews. We interviewed 2 managers at 2 of the companies (one hotel chain and one supplier). The reasons for this were that they were both big companies (+300 sites, +20,000 employees), so they have different departments and management positions with knowledge and expertise that could bring very interesting and complimentary inputs to our research (operations vs. sales; corporate sustainability vs. procurement). They were also available and open to share these different views with us.

The selection of companies to interview was carried out in the following way:

• Client companies (hotel chains): We classified the hotel chains into 3 groups (large, medium, and small) based on their size (number of hotels and rooms). Based on Loeda [93], we listed and ordered the hotel groups based on size, and we determined that large group includes the largest 15 hotel chains (representing 30.5% of hotels and 32.8% of rooms in Spain); medium group includes the next 59 hotel chains (representing 33.3% of hotels and 36.2% of rooms in Spain); and finally small group includes the remaining hotel chains (representing 36.2% of hotels and 31.0% of rooms in Spain). Three companies from the large group and two from the medium and small groups were selected according to the following criteria: Recognized companies within the group, with central offices located in the central zone of Spain, and accessible to the management team. In general, all the large hotel chains have centralized procurement departments (CPD), but only some medium and small chains have CPD.
• Supplier companies (industrial laundries): Industrial laundries were selected as supplier for this research because their activity is directly related to the three aspects of sustainability: (a) Their activity has a clear impact on the quality and service that the hotel chains provide to their guests (economic aspect); (b) industrial laundries are labour intensive (social aspect); (c) their production processes require the use and consumption of big quantities of water, energy, chemical products, gas, material (linen), etc. (environmental aspect). A classification of industrial laundries was carried out for 3 groups based on their size and geographical scope of activity. Small companies are not the object of this study. Three medium and large companies were selected.

The interlocutors were carefully selected according to the following criteria: Hierarchical responsibility in the company, ability to make decisions in relations between client and supplier, experience in the workplace and the industry, and experience and responsibility in the field of sustainability. In the hotel chains, the profiles that met these requirements were purchasing managers, operations managers, and managers in charge of sustainability. In the supplier companies, the profiles that met these requirements were factory managers, commercial directors, and managers.

Some considerations were evaluated in order to guarantee the quality of the information obtained in the interviews, such as their preparation and duration, the selection of the interviewers, the date, the place, and the recording process. The interviews were digitally recorded, with a second recorder as backup. The recording was completed with notes during the interview by the interviewer. This is convenient not only to record the subject’s voice, but also to observe the various reactions that occur throughout the interview [94].

The quality of the information obtained in the interviews depends on the collaboration of the interviewees, which entails “serious ethical obligations towards them” [94,95,96]. That is why informed consent, confidentiality, and consequence documents were prepared and signed, guaranteeing that the information from the interview: (i) Would not be disseminated to third parties; (ii) would only be part of the study in question; and (iii) would be included in this paper in such a way that no data, names, or numbers could help to identify the interviewee or the company.

A methodological field journal was kept, with the aim of recording the process of contact with interlocutors, the conversations that took place before the interviews, the introductory stages, and aspects related to the detailed observation during the interview or during other informal meetings. The purpose of this double recording was to perform a compared analysis with the recorded conversation during the interview session, in order to clarify certain nuances or circumstances. Once the interviews were carried out, they were transcribed within a period not exceeding 48 h. Transcription truthfulness and quality were guaranteed by a second person, who double-checked that the text corresponded authentically with the recordings.

Then, we proceeded to the coding of the transcribed interviews. This consisted of extracting the concepts from the original data and developing them in terms of their properties and dimensions [97], and this was carried out with the support of NVivo software. Initially, coding of the interviews followed a deductive approach: An interview script was elaborated from the research objectives and the theoretical framework, first categories were extracted from it, and the coding process was started (see Figure 1 for categories of analysis). From the transcripts, we continued the coding process, this time inductively: Based on a careful and precise reading of the interviews and the data obtained from them, definitive categories emerged. During this process, the contents were labelled, concepts were identified, and ideas were written down, so they could be used (if considered) to improve the script for the following interviews when rethinking new topics [97]. This codification process was completed with the reading of the field journal, from which ideas, nuances, and interpretations were also extracted that reinforced or questioned the information obtained, providing more solidity to our work.

Once all the resources and interviews were coded, we proceeded to a deep categorical and interpretative discourse and content analysis phase, aimed at interpretation. Discourse analysis was focused on analyzing the words and discourse used by the informants. The words used, the frequency of their use, and their relation to key concepts were studied, always bearing in mind the context of the conversation and the interviewee’s profile. NVivo software helped us build cloud marks of word frequency, statistics, and data tables. See Figure 2 for an example of a word frequency cloud mark for hotel chains.

Next, we proceeded to content analysis of the coded categories. For each category, the coded content was evaluated, comparing some interviews with others, information from hotel chains and suppliers, and different segments. Findings were obtained by detecting patterns to the extent that the information was repeated (saturation was achieved) or there were divergences in the discourse. From all this, relationships between the categories and elements were extracted, providing results that helped us to respond to the research objectives. See Figure 3 and Figure 4 for an example of the relationship of categories with each of the resources (interviews).

4. Results

In this section we present the findings or results of our research. The results are organized in two main subsections: (i) First, an evaluation of how companies in this sector follow the proposed models and frameworks from the literature; and (ii) second, findings on the identification of main drivers and barriers to effective implementation. It is important to mention that the semi-structured interview has been proven to be the best, if not the only, methodology to obtain the results that we present in this section. Some of the companies in this study do not have a website, and the ones with a website do not publish all information about sustainability practices. Their initiatives in SCM, and particularly SP, are not published and accessible. Surveys could have provided answers to some questions, but we considered that the depth, details, and nuances of the information that we were looking for could only be achieved through interviews with managers, experts in the hotel industry [87,88,89,90].

4.1. Evaluation of SP Practices

This section discusses the evaluation of the degree of implementation of SP in the supply chain of the hotel sector in Spain. It is done from the double perspectives of customers (hotel chains) and suppliers (industrial laundries).

In the literature review section, we identified different models for sustainability implementation in the purchasing function (see Table 1), and concluded that Leire and Mont’s [25] model is the most complete and adequate, as it details all implementation stages. The findings from interviews confirm that the implementation of SP in the hotel industry follows this model, singularly five stages: (i) Developing internal policies; (ii) setting purchasing criteria; (iii) applying assurance practices; (iv) managing supplier relations; and (v) building internal capacity.

Interviewees also mentioned that this model could be completed by incorporating the following ideas:

(i)

An initial stage, before stage 1, with a strong commitment from the top management of the hotel companies.

(ii)

An internal review at the end of each stage, with the aim of verifying, confirming, and validating completion of the stage before moving forward in the implementation process.

(iii)

The supplier point of view, meaning that in some stages, feedback from suppliers should be considered as a check or validating point.

Once the model was validated, we proceeded to assess how the hotel companies had implemented it. The results that we obtained vary depending on the different types of hotel chains.

In large hotel chains, sustainability awareness and the commitment of the company’s top management appear to be high, which is why they have developed initiatives internally. Once these initiatives were implemented within their organization, they were transferred to their suppliers. Large hotel chains have documented and formalized procurement processes, with a CPD at their headquarters. We account for initiatives in all five stages of Leire and Mont’s [25] model, although some missing points were detected: (i) Not all initiatives proposed by that model have been launched; (ii) some initiatives have been launched but not completed or have not been effectively implemented; and (iii) there are initiatives launched in all five stages, but none of the stages have been fully completed.

Currently we can say that large hotel chains are in a phase close to maturity according to the model of Leire and Mont [25], that is, with initiatives in all stages.

Table 4. Quotes from interviewees: Large hotel chain managers.

“The commitment to sustainability comes from top management here in Spain, who leads and promotes all the policies and activities carried out here, and this commitment reaches all employees. But, being a multinational company, all this comes to us from the headquarters, where it has been implemented for many years.”

“The company owns a very well-defined code of conduct. Part of an implication of the top management of the company, with a very specific mission and values.”

“These codes of conduct have been generated by our company in Spain, in the quality department, which is responsible for this, but they are based on the models that have been implemented internationally from the headquarters.”

“Top management is totally involved. Every document, corporate memory, code of conduct is preceded by a total commitment by senior management.”

“We have a very well-defined code of conduct. It starts with an implication of the top management of the company, with a very specific mission and values and the following sections: (a) Scope, application and compliance; (b) ethical and responsible behavior (general principles and commitment to stakeholders); (c) application procedure: advice and procedure to report complaints of the code of conduct; d) validity.”

“There is a large department of corporate purchasing that leads these activities towards suppliers. In matters of sustainability, it works in coordination with the department of sustainability and the environment, to the extent that purchasing requests it.”

”The code of conduct of the company has section with a code of conduct code of suppliers, to which they must adhere.”

“Adhesion to the code of conduct. The code of conduct forms part of the approval contract of the purchasing department since 2012. It includes an acceptance clause as an exclusion criterion in the selection phase of suppliers. They need to be qualified to participate in the following phases of the contest. Last year, 173 codes were signed, reaching the cumulative figure of 1391.”

“Purchasing management is responsible for the implementation.”

“The signing of the code of conduct is done during the approval process. A supplier is not approved if it has not signed the code.”

shows some quotes from interviews with large hotel chain managers on sustainability implementation in the purchasing function.

We obtained different findings for medium-sized hotel chains, depending on whether they have CPD or not. In general, all of them have defined purchasing procedures, although not completely documented and formalized.

In medium-sized hotel chains with CPD, sustainability awareness and the commitment of the company’s top management are moderate. Internal policies on sustainability are vague, so they are vague when transferred to suppliers. We account for initiatives in some stages of Leire and Mont’s [25] model (usually stages 1 and 2, none having been fully completed), and they are still far from carrying them to all stages. Some of these initiatives have been launched but not completed or have not been effectively implemented. Currently we can say that medium-sized hotel chains are in a phase close to introduction according to the model of Leire and Mont [25], that is, with initiatives only in one or two stages.

Table 5. Quotes from interviewees: Medium-size hotel chain managers (with CPD).

“The purchasing area is the leader for these initiatives.”

“We do not include these clauses in contracts with suppliers.”

“The purchasing tools and procedures are very professional. [...] The people who are part of the company have to become more professional and performant. These trends and practices come from a multinational environment.”

“On a national level I think that sustainability in hotel industry is not done, or very little.”

“It is an area for improvement that has started recently, but there is still a way to go, there are great potential.”

“In our income statement there is a part that is energy, that repeatedly showed very high numbers. It was the reason to do an in-depth study.”

“It works if it is a multinational or a large company. I suppose that multinationals put more weight on sustainability.”

“The national companies I would say that they do not meet any 15 or 20% with the sustainability criteria. Why? Because they do not care.”

“If we put weights, the truth is that the environment would be last. Yes, it is true that we are taking giant steps in this direction. But the price and the service are the key factors, and it cannot be otherwise in this moment of growth that we are having.”

“The government should put more effort to ensure compliance with legislation and regulations to enhance these measures. In the same way the media can play a role in their favour, as an intermediate point between government and clients.”

shows some quotes from interviews with medium-size hotel chain managers (with CPD) about sustainability implementation in the purchasing function.

Medium-sized hotel chains without CPD and small hotel chains present a similar approach to sustainability. In general, all of them have defined purchasing procedures, although not completely documented and formalized. None of them show any awareness or commitment from their top management to sustainability issues. The process of implementing some initiatives according to the model of Leire and Mont [25] has not begun within the companies themselves. Thus, if they do not believe in it and do not do it, they consider that they should not take any initiative on sustainability implementation with their suppliers.

Table 6. Quotes from interviewees: Medium-size hotel chain managers (without CPD).

“Small and medium-sized companies have little interest in sustainability.”

“Any hotel chain has significantly reduced the headcount, and apart from reducing the headcount, they have given more obligations to the remaining workers. Then, people do not have time.”

“What is clear today is that companies look more at the economic part than at the sustainability one.”

“The priority is cost reduction, without a doubt. It cannot be otherwise in the hotel sector in which we find ourselves and given the situation of general crisis and our exponential growth in these years.”

“If this approach (to be certified in sustainability) arose here in a steering committee, the answer would probably be that there are other priorities.”

“In the hotel sector the issue of certification is not as important.”

“It is not the same to be a national company as an international one. The multinational companies are forced to follow internal regulations different from the national ones.”

“This commitment requires in some way time, and time is money.”

“I do not believe that today the client is properly educated on this issue of sustainability. Yes, it is true that there are people who are involved and committed, but on the total of society this percentage is still low. Maybe if they were, it could be a sales argument. But they are not yet.”

“They do not do it because they surely do not have the requirement from their clients.”

“In Spain I think that sustainability culture is not yet spread, and if in future it may be, I think that it will come from the outside. This is how I see this sustainability issue.”

and

Table 7. Quotes from interviewees: Small hotel chain managers.

“I do not believe that society is aware, I honestly do not believe it.”

“In the hotel management, we can say that sustainability is not a priority.”

“First we have to make ourselves aware, I think.”

“The large hotel chains might probably do more things in this sense, but the vast majority we do not it.”

“I do not think that much is done about sustainability in the sector. At least it is not done in the hotels or in the hotel chains in which I have worked.”

“And if it’s not done in hotels like this, which is a 5-star hotel, less must be done in hotels with 1 to 3 stars.”

“I do not deny that there are large hotel chains working on it. Now, I do not know to what extent they will really do it, that is, there may also be a big difference between what they show on the website and reality.”

“I recognize that we are working on replacing luminaires with LED lamps. I admit that we are very sensitive to energy consumption, because of the costs.”

“If at the same time that we reduce costs, less waste is generated, then it would be great. But the trigger I think is the cost.”

“It takes time from my staff. And all this has a cost.”

“At a business level, what counts is the revenue and the results. Results are the main goal, comply with the budget, obtain the expected profit. The rest is not as high priority.”

“The shareholders, of course, are not aware. They only think about the results, the profit.

“If this crisis had never happened, the pressure for the result would surely be less intense, and I do not doubt that we would have evolved towards a more sustainable society. But now the criterion is the economic one.”

“Sometimes the application of regulations is necessary to change things and raise awareness.”

“We do not have support from the administration. There is a lack of resources, as information, containers for recycling, available and accessible disposal points, etc.”

“Companies would surely implement sustainability if they felt more pressure from the administration.”

“I do not think that customers demand sustainability at hotels. If they did, we would study the business case to analyze the profitability. I mean, if the number of customers grows significantly by being sustainable, then we would do it.”

“Sustainability is not a priority for us. Which is the main reason? The lack of space, the costs and dedication times, that we do not have. I am convinced that sustainability is not a priority for the hotel industry.”

“We do not have codes of conduct for sustainability. We do not have them internally, so we cannot ask the suppliers to comply with and sign them. I do not think that they exist in the hotel industry.”

“It is not our responsibility as a customer to make sure that our suppliers comply with sustainability or legal issues. It is their responsibility, as well as the administration responsibility.”

show some quotes from interviews with medium-size hotel chain managers (without CPD) and small hotel chain managers about sustainability implementation in the purchasing function.

4.2. Drivers and Barriers for an Effective SP Implementation

This research also identified the main factors that may influence the proper and effective implementation of sustainability in purchasing policies in the hotel sector. These factors could be drivers, facilitators, or catalysts insofar as they can help, facilitate, or promote these initiatives (positive approach). On the other hand, these same factors could also become barriers, obstacles, or limitations to the extent that they can hinder, slow, or prevent these initiatives (negative approach). For instance, the factor “commitment of the hotel chain management” could be:

(i)

A driver (positive approach): If the manager is committed, he/she will act as helper, facilitator, or promoter to support the implementation of these initiatives.

(ii)

A barrier (negative approach): If the manager is not committed, he/she will not support the implementation of these initiatives, becoming an obstacle, even stopping any related proposal.

A thorough analysis of all the interviews provides us with a list of factors, all previously identified in the literature (see Table 2 and Table 3). Factors have been classified into three groups:

(i)

Internal factors (within hotel chains), relating solely to management and decisions within the scope of the chain.

(ii)

Internal factors (in the relationship between hotel chains and suppliers), relating to management and decisions around the relationship between hotel chains and suppliers.

(iii)

External factors (in the hospitality sector), relating to aspects of agents in the hospitality sector outside the relationship between hotel chains and their suppliers.

The most relevant factors are:

Internal factors (within hotel chains):

• Awareness and commitment of the hotel chain management.
• Economic or cost factor for the implementation of these practices.
• Risk reduction and brand image and trying to enhance visibility.

Internal factors (in the relationship between hotel chains and suppliers):

○

Conflicts between hotel chains and suppliers on requirements to meet sustainability criteria and with a situation of increasingly lower prices and margins, or with operational criteria (product quality, service, delivery times).

External factors (in the hospitality sector):

○

Demand: Final consumers who request compliance with sustainability.

○

Requirements of regulations, governments, and public administrations.

○

Market situation in terms of demand, prices, and margins.

Likewise, other factors were identified by the interviewees, but they were rated or considered as less important. They refer to issues related to facility or installation design, lack of space, the cultural and multinational nature of companies, lack of knowledge, and growth and expansion of the hotel chain. Some interviewees described these secondary factors more as excuses than real factors, as they thought the main issue was a lack of commitment from the hotel chain management.

5. Discussion and Conclusions

The objective of this research paper was to describe and evaluate the degree of implementation of SP in the supply chain of the hotel sector in Spain from the double perspectives of customers (hotel chains) and suppliers (industrial laundries).

As a first step, we evaluated how companies in this sector follow the proposed models and frameworks in the literature. In Table 1, we presented a summary of the main models and frameworks from the literature. After a thorough analysis and as a result of our field work, we concluded that Leire and Mont’s [25] model is the most adequate for SP implementation. We chose this model as a basis for our study because it has a clear focus on the practical implementation of sustainability purchasing in terms of (i) describing each stage and phase; (ii) identifying the responsibilities in these stages; (iii) identifying the factors that influence an adequate implementation; (iv) presenting a tool for decision making; and (v) being applicable to any sector. During the interviews, new ideas and proposals arose with the aim of completing this model. These proposals refer to incorporating new activities in the model; as: (i) An initial stage, about a strong commitment from the top management of the hotel companies; (ii) an internal verification and validation review at the end of each stage; and; (iii) feedback from suppliers as a check or validating point.

We detected a general lack of awareness of, or commitment to, incorporating sustainability within the purchasing function in SCM in the hotel sector. One reason could be that the study was carried out in the years after a big economical and financial crisis (2014–2019), so the economic factor is predominant in company decisions versus other aspects such as social or environmental.

Previous sections showed that we obtained different results depending of the type of hotel chain. Molina-Azorín et al. [53] proposed a classification of hotels based on a cluster analysis of how proactive/reactive they were about their environmental policies. This taxonomy cannot be strictly applicable to our study, as we consider a wider scope of analysis in two ways: (i) We analyze sustainability, which includes environmental, economic, and social aspects; and (ii) we study how it is implemented in the purchasing function, and not within the hotel company. Thus, a taxonomy of companies with different purchasing categories is proposed based on our findings in previous sections (see

Table 8. Hotel chain classification related to the degree of implementation of SP.

Classification	Purchasing Processes	Model Stages	Hotel Chains
Advanced	Formalized	1, 2, 3, 4, 5	Large
Elementary	Defined	1, 2	Medium (with CPD)
Passive	Defined	None	Medium (without CPD) Small

).

“Advanced” refers to the group of large hotel chains with documented and formalized purchasing processes and implemented initiatives in SP at all five stages of Leire and Mont’s [25] model, although we discussed that the implementation level is not complete in general.

“Elementary” refers to the group of medium hotel chains with defined purchasing processes and CPD. They have partially implemented initiatives in SP stages 1 and 2 of Leire and Mont’s [25] model.

“Passive” refers to the group of medium hotel chains with defined purchasing processes and no CPD. They have not implemented any SP initiatives.

This research also identifies the main factors that may influence the proper and effective implementation of sustainability in purchasing policies in the hotel sector. These factors could act as drivers or barriers, and we grouped them into three types: (i) Internal factors (within hotel chains); internal factors (in the relationship between hotel chains and suppliers); and external factors (in the hospitality sector). Carefully analyzing these factors, we can conclude, on the one hand, that they are all part of what the literature identified (see Table 2 and Table 3). Although the literature identified other factors, we must admit that our interlocutors did not consider them relevant. On the other hand, the literature exposes factors classified into two large groups, drivers and barriers; instead, our research allows us to conclude that the same factors that could act as drivers could also act as barriers depending on the way they are applied, as explained previously.

We can conclude that several of the factors refer to the potential conflict that could arise between the three aspects of sustainability (economic, environmental, and social) insofar as a hotel chain does not want to renounce consideration of the economic aspect in favour of the environmental and social aspects. This can be seen in the factors that deal with costs and investments, prices and margins, quality and service. Another group of factors is related to the commitment to, and awareness of, sustainability, both by the management of hotel chains (whose initiative and leadership are necessary for the implementation of these practices), and by governments, customers, and markets, which, each in its scope, may motivate companies and require them to comply with sustainability criteria themselves and in their purchase from suppliers.

This paper is of practical and social interest, and offers managerial implications, as the results of this study provide meaningful guidelines for different stakeholders (users, customers, suppliers, society, governments, employees, etc.). From a practical point view, we would like to propose some recommendations and initiatives in the direction of supporting the drivers or factors for effective implementation of SP in the hotel industry.

First, we suggest continuing to promote consciousness and commitment from society in general, and hotel guests and customers, in particular. This could be achieved with communication and awareness programs by governments, entities, agencies, or media. Lessons learned from more developed countries could be brought to this topic. When individual customers are committed, they will demand it from hotel chains. Corporate and group customers commitment towards sustainability is also very important, and as they manage high volumes in terms of sales for the hotel chains, they can exert higher power to them oriented towards demanding the implementation of sustainable practices within the hotels and SP practices towards their suppliers.

Second, the implication of the government must also be manifested in other directions, such as: (i) Launching initiatives with the aim of standardizing, simplifying, and clarifying the different regulations that concern aspects of sustainability; (ii) putting in place mechanisms of pressure to ensure that these regulations and laws are respected; and (iii) providing support and resources for hotel chains (such as glass hoods, containers, delivery points, and nearby waste collection).

Third, support should be provided to raise the consciousness of, and commitment by, hotel chain management. The above-mentioned recommendations could help, in the same way that other results from this paper could help them understand that sustainability practices in SCM are a means to achieve competitive advantage rather than a cost conflict issue. Redesigning processes and contract relations in SCM should be a strategic decision.

This research is bound by certain limitations, as are many other studies. First, we limited our interviews to 15, which was enough for our research purposes, but could be extended in future research, and even supported by a survey. This could reach a wider population and different management profiles that could help researchers obtain more data and information, and richer results with the aim of evaluating the applicability of the proposed SP model. This could also be done by different typologies of hotels (for instance, rural, holidays, city hotels), and tests of the applicability of the proposed SP model could be carried out in each of these typologies.

Second, we limited our study to a very specific geographical area (Spain) and period (2014–2019). By extending the research to other geographical areas researchers could have the opportunity to assess how SP is implemented in the hospitality industry in different societies with different levels of consciousness compared to Spanish society. It would also be a good opportunity to evaluate the applicability of the proposed SP model.

Third, we focused on one specific type of supplier, industrial laundries, with a clear impact in the three dimensions of sustainability, but this could restrict the applicability of results. Therefore, research could be extended to other suppliers (for instance, room cleaning companies, maintenance companies, etc.) with different operational contexts and constraints. For instance, room cleaning companies are also labour intensive and deal with environmental issues (use of chemical products) but in a different manner than industrial laundries (less water and energy consumption, as an example).

Fourth, research could also be extended to other members within the supply chain (for instance, tier 2 or tier 3 suppliers). It could be interesting to assess how SP practices are implemented in tier 2 and tier 3 suppliers, evaluating the different roles of the hotel chains and the tier 1 suppliers, and testing the applicability of the proposed SP model.

Fifth, we consider that the lack of certified or labelled hotels in our analysis may be a limitation. It would also be interesting to carry out a comparative analysis of certified or labelled hotels versus non-certified hotels with the aim of evaluating sustainability policies, how they have been implemented towards their suppliers, as well as the applicability of the SP model in both contexts.