1. Introduction
In order to stay ahead in today’s competitive business landscape, it is crucial for companies to collaborate closely with external partners. Therefore, their attention should be directed towards the identification and selection of reliable suppliers. The selection of suppliers plays a major role in determining the competitiveness of an entire supply chain network [
1]. The process of selecting suppliers is a vital part of strategic operations, and making incorrect decisions in this area can lead to severe and wide-ranging consequences [
2]. Supplier management is considered a critical aspect of supply chain management, as it has implications for the overall performance and long-term relationships of a company. It is particularly significant for companies to allocate a significant portion of their sales revenue towards purchasing raw materials [
3,
4]. Hence, selecting the right suppliers is a crucial decision-making process aimed at minimizing purchasing risks, maximizing the overall value of purchases, and fostering enduring and close relationships with suppliers [
5,
6].
In the meantime, the availability of different suppliers with different capabilities complicates the selection process. Supplier selection is a process during which the best combination for meeting firm needs is selected from among the existing potential suppliers [
7]. The process of selecting the best supplier, carried out to reduce the number of suppliers, can potentially lead to a competitive advantage for the manufacturer. This is achieved through attaining reduced costs, improved quality, and advancements in both process and product development. In fact, the main benefit of reducing the number of suppliers is that it provides more time to establish closer relationships with the remaining suppliers [
8,
9,
10]. Scholars have employed various methods, such as Markov chains, deterministic and stochastic optimization, Bayesian networks, and simulation, for supplier selection. However, the topic of sustainable supplier selection in terms of resilience and sustainability has not been explored in previous studies [
11,
12,
13,
14,
15,
16,
17,
18,
19,
20,
21,
22,
23,
24,
25,
26,
27,
28,
29,
30,
31,
32,
33,
34,
35,
36,
37,
38,
39,
40,
41,
42,
43,
44,
45,
46,
47,
48,
49,
50,
51,
52,
53,
54,
55,
56,
57,
58,
59,
60,
61,
62,
63,
64,
65,
66,
67,
68,
69,
70,
71,
72,
73,
74,
75,
76,
77,
78,
79,
80,
81,
82,
83,
84,
85,
86,
87,
88,
89,
90,
91,
92,
93,
94,
95,
96,
97,
98,
99].
Baki [
2] proposed a model using structural equation modeling and fuzzy ARAS to address the issue of green supplier selection, incorporating eight primary criteria and twenty-seven sub-criteria that considered classical, green, and social aspects. Sonar et al. [
11] identified 12 key criteria influencing supplier selection within the LARGS paradigm and examined the interconnections between these criteria using interpretive structural modeling. Sahu et al. [
100] proposed 63 measures for supplier selection based on LARGS (Lean, Agile, Resilient, Green, and Sustainable) criteria and utilized an integrated MCDM approach combining AHP, DEMATEL, ANP, Extended MOORA, and SAW techniques to assess suppliers. Tavana et al. [
101] employed fuzzy group BWM and the FCoCoSo method for supplier selection in a reverse supply chain, focusing on LARG factors. Sheykhzadeh et al. [
102] conducted a case study using fuzzy BWM and Fuzzy ARAS to evaluate the role of lean, agile, resilient, and green (LARG) criteria in the operations of a pharmaceutical supply chain distributor. Alimohammadlou and Khoshsepehr [
103] developed hesitant fuzzy BWM, HFEDAS, HFCODAS, HFARAS, HFCOPRAS, HFWASPAS, and HFVIKOR based on green–resilient factors in the supplier selection process. Anvari [
60] proposed a conceptual framework to investigate the integration of LARGS paradigms in the context of supply chain management and subsequently applied an integrated approach based on fuzzy AHP and fuzzy VIKOR to prioritize LARGS factors.
While the existing literature offers numerous analytical models for supplier selection, our research reveals a significant gap in the integration of structural equation modelling (SEM) and intuitionistic fuzzy Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) analysis with the use of lean, agile, green, resilient, and sustainable (LARGS) criteria. To address this gap, our study aims to develop an innovative approach that combines SEM and intuitionistic fuzzy TOPSIS analysis for sustainable supplier selection. SEM and intuitionistic fuzzy TOPSIS were selected because of their distinct advantages in addressing the complexities associated with LARGS criteria in supplier selection. SEM enables the assessment and estimation of causal relationships by utilizing both quantitative and qualitative data. The utilization of partial least squares (PLS)-based SEM provides a powerful and flexible approach for modeling complex data relationships, leading to reliable and accurate outcomes. PLS is particularly well suited for analyzing data exhibiting high dimensionality and multicollinearity and with small sample sizes. Therefore, incorporating PLS within the SEM framework enhances the rigor and accuracy of our approach, ensuring that the findings derived from our study can be trusted and applied in practice. On the other hand, intuitionistic fuzzy TOPSIS is a multi-criterion decision-making (MCDM) approach that effectively handles decision making under conditions of uncertainty and imprecision, making it suitable for tackling the inherent uncertainties in sustainable supplier selection processes. By addressing the research gap related to the integration of SEM, intuitionistic fuzzy TOPSIS, and LARGS criteria, our study contributes to the advancement of knowledge on sustainable supplier selection. This integration is crucial, as it enhances the current understanding of how organizations can effectively evaluate and select suppliers based on LARGS criteria, ultimately promoting sustainable practices throughout the supply chain. In addition, many scholars have attempted to use MCDM methods combined with classical fuzzy concepts to overcome uncertainties and ambiguities in decision-making problems [
12,
13,
14]. However, since the development of fuzzy methods such as intuitionistic fuzzy sets is an efficient, effective, and flexible method for investigating decision-making problems, the present study intends to use TOPSIS combined with an intuitionistic fuzzy set approach to solve the supplier selection problem by integrating lean, agile, green, resilient, and sustainable aspects of the supply chain. The validity if this approach was confirmed by applying the SEM method in a case study.
The remaining parts of this paper are structured as follows:
Section 2 reviews the relevant literature.
Section 3 describes the proposed methodology. In
Section 4, the results obtained using the proposed methodology are discussed and tested using a sensitivity analysis. Finally,
Section 5 concludes our work.
3. Research Methodology
The methodology used in the present study involves third-order factor analysis and partial least squares for analyzing the proposed conceptual model. Third-order factor analysis is a statistical method that aids the identification of latent variables, which are constructs that cannot be directly measured but can be inferred based on observed variables. This method was chosen because it allowed us to model complex relationships between observed variables (26 criteria for supplier selection) and latent factors, thereby providing a comprehensive insight into the underlying structure of our data. Moreover, the third-order factor analysis helped us to identify the underlying latent variables, while PLS enabled us to model the structural relationships between these factors and the observed variables. Also, for supplier selection and evaluation, intuitionistic fuzzy TOPSIS analysis was applied. Additionally, the weights assigned to the experts for evaluating suppliers using the Intuitionistic Fuzzy TOPSIS method were not equal.
3.1. Population and Sample
To ensure the representativeness of the sample, specific criteria were employed. The statistical population comprised managers and deputies of the supply chains in large and medium-sized manufacturing companies listed on the Tehran Stock Exchange, including those from the automobile, car-utility, pipe-and-faucet, electric utility, clothing, food, chemical, mining, pharmaceutical, and petrochemical industries. A random selection process was used to select 200 companies with more than 50 employees from the entire pool of manufacturing companies. This approach was designed to minimize bias and ensure transparency, thereby increasing the generalizability of the findings to the larger population. Efforts were made to contact the supply chain managers and deputies of the selected companies based on their roles and responsibilities within the supply chain. This ensured that the respondents possessed the knowledge and expertise necessary for providing insightful responses. However, potential limitations, such as response bias or the exclusion of individuals who were not available or willing to participate, should be acknowledged. To achieve a representative sample, 330 questionnaires were distributed among these supply chain managers and deputies of the selected companies. Of these, 237 (72%) were filled out and returned, providing valuable insights into the research objectives. In the second phase, a case study on the automotive industry was conducted to evaluate and select suppliers.
3.2. Data Collection Instruments
A questionnaire with 87 items was developed to measure the identified variables in the first phase. A five-point Likert scale, ranging from completely disagree (1) to completely agree (5), was used to measure all items to attain reliable and valid responses. The five-point Likert scale is widely used in social science research and is suitable for measuring attitudes, opinions, and perceptions. Two separate questionnaires were utilized in the subsequent phase, focusing on the importance of criteria and the ratings of suppliers, respectively. The use of a five-point Likert scale ensured consistent measurement across items, enhancing the reliability and validity of the collected data. This approach facilitated a focused data collection process, contributing to the rigor of this study.
4. Results
Our structural model utilizes a third-order factor analysis with three hierarchical levels. At the first-order level, a combination of indicators or questions accounts for lean components (e.g., price, lead time, just-in-time practices, defect reduction, and collaboration with the supply chain), agile components (e.g., innovation capability, response speed, dynamic alliance, new production line capability, and flexibility), resilient components (e.g., the ability to deal with unexpected disruptions, resilient transportation, strategic capacity and inventory buffer, supply chain risk management culture, and capacity for mass customization), green components (e.g., green innovation, green products, environment management systems, renewable energy/initiatives, waste recycling, and environmental competence), and sustainable components (e.g., life cycle assessment systems, long-term relationships, sustainable measuring criteria, reputation, and cooperation among various entities in the supply chain). The amalgamation of these indicators yielded five components—lean, agile, resilient, green, and sustainable—comprising the second order of the model. Finally, from the combination of these five components, a general variable named LARGS supplier selection was obtained.
To delve into the validation process, we assessed construct validity by examining the factor loadings in the confirmatory factor analysis. A factor loading exceeding 0.6 for each indicator with its construct indicates that each item adequately represents said construct [
92,
93]. The factor loadings are presented in
Table 2. In the structural equation model, both construct and discriminant validity are crucial. Construct validity assesses the importance of the chosen indicators in measuring the constructs, while discriminant validity ensures that the indicators of each construct effectively differentiate themselves from those of other constructs. The average variance extracted (AVE) is utilized to assess discriminant validity, with Fornell and Larcker [
94] suggesting that a threshold of 0.50 or higher should be set. As shown in
Table 2, all the studied constructs have AVE values exceeding 0.5.
Reliability was evaluated through composite reliability and Cronbach’s alpha coefficient. Values above 0.7 for each construct demonstrate satisfactory reliability [
93].
Table 2 displays the factor loadings, composite reliability, and AVE of the variables, indicating robust validity and reliability across the constructs.
Utilizing SmartPLS4 software for its ability to analyze second-order factor models, we explored latent factors influenced by a higher-level latent variable. The second-order factor analysis results, including the factor loadings and t-values for indicators linked to each construct, are presented in
Table 3. All the components of LARGS exhibit factor loadings exceeding 0.7 and t-values exceeding 1.96 (
p > 0.05), confirming the significance and relevance of the chosen indicators.
Transitioning to a third-order factor analysis, the lean, agile, resilient, green, and sustainable components each have indicators serving as markers, necessitating this analysis. The questions were subjected to an analysis using third-order factor analysis, and the findings are provided below. For path coefficients and R
2 values, the Partial Least Squares (PLS) method was employed to examine the theoretical model and hypotheses. T-values were calculated using the bootstrap method, with 500 sub-samples. Factor loadings, R
2 values, and Stone-Geisser’s Q2 [
95] coefficient are presented in
Table 4, indicating significant explained variances for the lean (0.766), agile (0.798), resilient (0.817), green (0.879), and sustainable (0.820) components. Positive Q2 values suggest substantial predictability.
Table 4 reveals positive and significant effects of leanness (β = 0.875,
p < 0.001), agility (β = 0.894,
p < 0.001), resilience (β = 0.904,
p < 0.001), greenness (β = 0.938,
p < 0.001), and sustainability (β = 0.906,
p < 0.001) on supplier selection.
Figure 1 illustrates the tested model, depicting the factors influencing supplier selection, with the numbers within the circles representing the magnitude of explained variances.
In general, the goodness-of-fit (GOF) index in PLS serves as a measure for assessing the validity and quality of a PLS model. It evaluates the model’s collective predictive capacity and determines if it successfully predicts the endogenous variables. In this study, the tested model displayed a GOF value of 0.67, indicating a good fit. Values exceeding 0.36 suggest satisfactory and acceptable levels of quality for a model [
96].
5. Evaluation of Suppliers in a Case Study
This research paper focuses on a case study of the supply chain department in an Iranian automotive company. This department is responsible for providing parts to the production lines of an automotive manufacturing company. Its primary objective is to identify and select automotive parts suppliers for both domestic and international markets. The main challenge faced by this department concerns choosing the most suitable supplier and allocating demand suppliers under uncertain environments, using LARGS indicators that align with the company’s requirements. To evaluate suppliers, a committee comprising four experts with extensive experience in the automotive industry (each having over 10 years of work experience) was formed. The committee consisted of a supply chain manager, a procurement manager, a specialized purchasing expert, and a specialized logistics expert. As shown in
Figure 2, four suppliers were considered in the study, taking into account 26 criteria that had significant and positive effects, as confirmed using the SEM method. Four suppliers were considered in the study, taking into account 26 criteria that had significant and positive effects, as confirmed using the SEM method. In this study, it is supposed that there is no dependency between the criteria. Subsequently, the following section presents the results of the proposed steps for implementing the intuitionistic fuzzy TOPSIS analysis introduced by Rouyendegh [
97] in a case study.
Initially, the level of significance for each decision maker was established by utilizing a designated linguistic variable and employing intuitionistic fuzzy numbers (IFNs) in accordance with the information presented in
Table 5.
Assuming that the importance of each decision maker is based on IFNs represented as Dk = (
μ_k,v_k,π_k), where is the degree of membership function, is the degree of non-membership function, and is the hesitation degree, then the final weight of the
k-th DM can be determined as shown in (1).
DM1 and DM2 were classified as “very important,” DM3 was classified as “important,” and DM4 was classified as being of “medium” importance. Subsequently, the determination of the importance weights for these decision makers was carried out. The importance weights of DM1 to DM4 are 0.289, 0.289, 0.253, and 0.169, respectively.
The group decisions were aggregated using Equation (2) by applying the Intuitionistic Fuzzy Weighted Averaging (IFWA) operator proposed by Xu [
98] based on the linguistic terms and intuitionistic fuzzy numbers presented in
Table 5.
The criteria’s importance is indicated by the linguistic terms listed in
Table 6. Numerical representations of the linguistic terms can be found in
Table 5 corresponding to step 2. The criteria weights were ultimately aggregated and are displayed in
Table 6.
By referring to the numerical equivalents of the linguistic terms as provided in
Table 7, the ratings for the alternatives were determined. In order to achieve this, it was necessary to combine the individual opinions obtained from a group of DMs into a unified viewpoint. This unified viewpoint was then used to create an aggregated intuitionistic fuzzy decision matrix (IFDM). The IFWA method, as shown in
Table 8, was utilized to calculate the IFDM, taking into account the preferences of the decision makers.
The computation of an aggregated weighted intuitionistic fuzzy decision matrix can be carried out by utilizing the definitions provided in Equation (3) after the determination of criteria weights (W) and the creation of an aggregated IFDM (R matrix), as stated by Memari [
99].
To calculate the intuitionistic fuzzy positive-ideal solution and intuitionistic fuzzy negative-ideal solution, the positive and negative criteria were denoted as
J+ and
J−, respectively.
In this research, the first two criteria, namely, price and lead time, are classified under the cost category, while the remaining criteria fall into the profit category, please check
Table 9.
This research paper utilizes the normalized Euclidean distance as a means of quantifying the separation of each alternative, denoted as
and
, from
A+ and
A−.
The computation of the relative closeness coefficient (
) for alternative Si was achieved using Equation (8). The resulting values are presented in
Table 10. As a consequence, the best supplier in terms of LARGS criteria, S4, was identified, and the ranking of the alternatives was determined to be S4 > S1 > S2 > S3.
To demonstrate the applicability and effectiveness of the proposed methodology, we conducted a comparative analysis, using the fuzzy TOPSIS method proposed by Nazari-Shirkouhi et al. [
14] and Samadi et al. for comparison [
105]. The relevant results for the fuzzy TOPSIS method are shown in the last column of
Table 10. In this regard, the intuitionistic fuzzy TOPSIS method effectively differentiates between the alternatives’ diversity, while there is not much difference when ranking the alternatives using the fuzzy TOPSIS method.
6. Managerial Implication
This study aims to introduce a supplier selection model grounded in the LARGS paradigm, encompassing lean, agile, resilient, green, and sustainable principles. The findings indicate that the model was able to successfully align with the data, demonstrating the efficacy of incorporating LARGS factors in the supplier selection process.
The results show the role of leanness in supplier selection, emphasizing that leanness should be considered in supplier selection. This finding is consistent with the results presented in [
11,
53,
54,
55,
62,
63,
65]. This finding indicates that leanness focuses on eliminating waste, reducing inventory during manufacturing, increasing material speed in the supply chain, and decreasing preparation time in the production and transportation processes. Lean manufacturing also plays a crucial role in reducing waste in the logistics system. The cost of transportation accounts for 15–40% of the finished price of products. By decreasing inventories and transportation in the logistics system through lean suppliers, there will be a significant reduction in the final price, leading to increased competitiveness and improved business processes.
This study demonstrates the significance of supplier agility in the selection process, highlighting the importance of considering agility when choosing suppliers. This conclusion aligns with the findings presented in previous research [
11,
66,
67,
68,
71,
72,
73,
74]. Essentially, the findings emphasize that suppliers should possess the ability to promptly adapt to environmental changes, quickly recognize opportunities and threats, readily obtain necessary information from both suppliers and customers, make decisive decisions to manage environmental changes, effectively respond to market fluctuations, adjust short-term capacity as required, and modify order specifications based on customer demands.
The study’s results highlight the significance of resilience in supplier selection and emphasize the need to consider resilience when choosing a supplier. This finding aligns with previous findings presented in [
15,
22,
62,
72,
75,
77,
78]. Based on this finding, it is crucial to select a supplier that can effectively respond to unexpected disruptions by swiftly restoring product flow, promptly recovering from disruptions, attaining a new and improved state after disruptions, adequately managing financial implications arising from potential supply chain disruptions, and maintaining optimal control over the structure and performance throughout disruptions.
The results demonstrate the importance of considering the environmental sustainability of suppliers when selecting them. This finding aligns with the results of previous studies [
53,
54,
60,
72,
80,
81,
83,
84]. It highlights the significance of managing and coordinating relationships with suppliers and incorporating environmental sustainability practices into a supply chain for long-term success. From a broader perspective, integrating environmental considerations is crucial for enhancing the capacity to develop green products and creating markets for environmentally friendly products. Implementing a green supply chain necessitates adopting new approaches, providing companies with opportunities to invest in designing and producing greener products to meet market demands. This not only involves consumer products but also encompasses collaborating with suppliers to establish green markets. Beyond cost reduction, a green supply chain facilitates the expansion of the range of available sustainable products through close collaboration with suppliers. In order to succeed, it is essential for companies to reassess their products and ensure their compatibility with the environment, establishing strong partnerships with suppliers in this process.
The findings of this study demonstrate the significance of considering environmental sustainability in supplier selection and emphasize the need to consider sustainability when choosing suppliers. These results align with the findings presented in previous research [
11,
79,
80,
83,
87,
88,
89,
90,
91]. Accordingly, it is recommended that companies prioritize suppliers who actively strive to reduce energy and material consumption, focus on reusing recycled materials, utilize environmentally friendly materials in when manufacturing products, design products with standardized parts for easy reuse, facilitate product disassembly, employ life cycle analysis to assess environmental impacts, have official guidelines for sustainable product design, continuously update processes to minimize environmental impacts, and promote eco-friendly relationships in their production processes. The adoption of sustainable supply chain management offers various benefits, including environmental advantages, improvements in supply chain satisfaction, access to new markets through the supply of eco-friendly products, cost reductions achieved through resource savings, lower fuel costs, reduced working hours for employees, waste elimination, and enhanced productivity. Furthermore, implementing sustainable practices provides a competitive edge by creating value and delivering it to customers in terms of product quality, thereby leading to increased profitability.
7. Conclusions
In conclusion, this study has provided valuable insights into the significance of the LARGS paradigm in supplier selection. The findings highlight the importance of considering the lean, agile, resilient, green, and sustainable paradigm in order for companies to gain a competitive advantage. However, it is important to acknowledge the limitations of this study and consider potential hurdles with respect to implementing the proposed supplier selection model in different contexts. One limitation of this study is that the interdependencies among criteria and sub-criteria were not considered. This could have influenced the results; therefore, future research should aim to address this limitation. One possible avenue for further investigation is to assess the interdependencies among criteria and sub-criteria using the Analytic Network Process (ANP). By incorporating the ANP methodology, researchers can gain a more comprehensive understanding of the relationships among various criteria and their impacts on supplier selection outcomes. Additionally, the application of the intuitionistic fuzzy ANP method, which considers the interrelationships among criteria or alternatives, could be considered as an extension of this work. Furthermore, a sensitivity analysis assessing how changes in criteria weights impact the results can be conducted. A more extensive comparative analysis or benchmarking against industry standards or competitors would provide a broader perspective of supplier selection practices. Longitudinal studies can be undertaken to assess the long-term effectiveness of the suppliers selected using the proposed model. Additionally, integrating qualitative data into the supplier selection process by considering factors such as trust, communication, and cultural compatibility would provide a more holistic evaluation. Dynamic supplier selection models that consider changes over time should also be explored, as they can capture the dynamic nature of supplier performance. It is important to incorporate risk management considerations into the supplier selection process to ensure that potential risks are properly evaluated and managed. Lastly, a framework for evaluating the environmental impact of suppliers should be developed to promote sustainable supply chain practices. This would enable companies to prioritize suppliers based on their environmental footprints and contribute to a more sustainable business ecosystem. In summary, while this research underscores the importance of the LARGS criteria in supplier selection and presents an effective integrated approach using SEM and intuitionistic fuzzy TOPSIS analysis, there are several areas for further exploration. By considering the interdependencies among criteria and sub-criteria and incorporating the suggested avenues for future research, researchers can enhance the understanding of supplier selection processes and provide valuable insights for managers seeking to improve their supplier selection practices.