UNIVERSIDAD DE JAÉN ESCUELA POLITÉCNICA SUPERIOR DEPARTAMENTO DE ORGANIZACIÓN DE EMPRESAS, MARKETING Y SOCIOLOGÍA TESIS DOCTORAL HUMAN RESOURCES, ENVIRONMENTAL RISK AND IMPLEMENTATION OF LEAN PRODUCTION. THE CASE OF THE FIRST TIER SUPPLIERS OF THE AUTOMOTIVE INDUSTRY IN SPAIN PRESENTADA POR: ÁKOS UHRIN DIRIGIDA POR: DR. D. SEBASTIÁN BRUQUE CÁMARA DR. D. JOSÉ MOYANO FUENTES JAÉN, 21 DE ABRIL DE 2017 ISBN 978-84-9159-067-5 “Everything will be all right in the end. If it’s not all right, it is not yet the end.” ― Simit Patel ACKNOWLEDGEMENT ‘Keep going!’ my mother used to tell me reassuringly whenever I came across a challenging situation throughout my studies. After all, there are certain things in one's life that require a huge amount of commitment to bring off. Undoubtedly, however, the backing of people of good will whom you encounter along your way is as much important as having the will to carry on even if at the beginning you do not see clearly where the journey you are undertaking leads you. Indeed, the endeavor to pursue a PhD degree means the road less traveled. Not only metaphorically speaking, but in practical terms as well, since the candidate must dwell into a field of research and demonstrate that they are able to create something novel and push the boundaries of science forward in such a meticulous way that occasionally tests their limits. Therefore, every now and then you find yourself in need of guidance, which fortunately I never lacked. For this reason, I feel grateful to a number of different but equally important people who have provided me with professional or emotional support. To Beáta Udvari, who inducted me into the realm of science. To Tamás Schuszter, who kept me going after my first attempts. To Anita Pelle, who broadened my perspective and showed me that the world is full of opportunities. To my dear friends, Balázs, Gábor, Martin, Peti and Ricsi, who never stopped believing in me. To Melcsi and Soma, who cheered me up when I was disheartened. To the Department of Business Administration, Marketing and Sociology of the University of Jaén for providing me with the possibility to continue with my research. To my supervisors, José Moyano, who taught me the most valuable analytical thinking and who not only contributed enormously to my professional progress but also stood next to me as a friend and to Sebastián Bruque, who gave me the possibility to pursue my PhD studies at the University of Jaén and established the circumstances for it, as well as supported me both professionally and emotionally. Last but not least to my wonderful family that was given to me, Judit, Attila and Csenge, for their love, care and wise guidance and for their being the source of my strength and peace of mind. In Jaén, February 4, 2017 Table of content Introduction ................................................................................................................. - 1 - I. Background of the research ....................................................................................... - 3 - I.I The origins and evolution of lean production....................................................... - 3 - I.II. Motivation of the doctoral dissertation and its main objectives ........................ - 6 - II. Methodological approaches .................................................................................. - 11 - III. Structure of the thesis ........................................................................................... - 13 - IV. References ............................................................................................................ - 15 - Chapter 1. Lean production and human resources: A systematic literature review ......................................................................................................................... - 18 - 1.1. Introduction ...................................................................................................... - 19 - 1.2. Methodology .................................................................................................... - 24 - 1.2.1 Research design .............................................................................................. - 25 - 1.3. Results and discussion ..................................................................................... - 30 - 1.3.1. The role of socio-cultural factors in the implementation andconsolidation of lean production ................................................................................................... - 32 - 1.3.2. The effect of work organization in the implementation andconsolidation of lean production ................................................................................................... - 35 - 1.3.3. The impact of trade unions in the implementation and consolidation of lean production ................................................................................................... - 37 - 1.3.4. The influence of knowledgeable workforce and participative management on lean production implementation and consolidation ..................... - 39 - 1.4. Conclusions ...................................................................................................... - 41 - 1.5. References ........................................................................................................ - 46 - Chapter 2. Lean production, workforce development and operational performance .............................................................................................................. - 77 - 2.1. Introduction .......................................................................................................... - 78 - 2.2. Research background and hypotheses ................................................................. - 80 - 2.2.1. Lean production ............................................................................................ - 80 - 2.2.2. The role of workforce development in lean production ................................ - 81 - 2.2.3. Operational performance .............................................................................. - 82 - 2.3. Hypotheses ........................................................................................................... - 83 - 2.4. Research methodology ......................................................................................... - 88 - 2.4.1. Data collection and sample characteristics .................................................. - 88 - 2.4.2. Measures ....................................................................................................... - 91 - 2.4.3. Model testing ................................................................................................. - 96 - 2.5. Results .................................................................................................................. - 97 - 2.6. Discussion ...................................................................................................... - 101 - 2.7. References ...................................................................................................... - 103 - Chapter 3. Self-reference on past performance and firm risk as predictors of lean production implementation .................................................................................... - 113 - 3.1. Introduction ........................................................................................................ - 114 - 3.2. Literature and hypotheses .................................................................................. - 116 - 3.2.1. Lean production .......................................................................................... - 116 - 3.2.2. Firm risk ...................................................................................................... - 117 - 3.2.3. Past performance and decision-making ...................................................... - 119 - 3.3. Hypotheses ......................................................................................................... - 120 - 3.4. Research methodology ....................................................................................... - 125 - 3.4.1. Data collection and sample characteristics ................................................ - 125 - 3.4.2. Measures ..................................................................................................... - 128 - 3.4.3. Model testing ............................................................................................... - 132 - 3.5. Results ................................................................................................................ - 133 - 3.6. Discussion and conclusion ................................................................................. - 135 - 3.7. References .......................................................................................................... - 138 - Tables index Chapter 1. Lean production and human resources: A systematic literature review ...................................................................................................................... 18 Table 1.1. Main characteristics of the methodological approach ............................ 26 Table 1.2. Keywords employed in the searches conducted ..................................... 26 Table 1.3. Search strings for database search .......................................................... 27 Table 1.4. Inclusion criteria ..................................................................................... 29 Table 1.5. Literature classification .......................................................................... 31 Chapter 2. Lean production, workforce development and operational performance ........................................................................................................... 77 Table 2.1. Industry distribution of the sample and the population .......................... 90 Table 2.2. Lean production practices ....................................................................... 92 Table 2.3. Workforce development ......................................................................... 93 Table 2.4. Operational performance ........................................................................ 94 Table 2.5. Means, standard deviations and Pearson correlations coefficients ......... 95 Table 2.6. Testing for moderation ........................................................................... 97 Table 2.7. Analysis of regression of relationship of LP and WFD on operational performance ............................................................................................................. 98 Table 2.8. Analysis of regression of influence of LP on WFD ............................... 99 Table 2.9. Results of the regression analyses for Hypothesis 4 ............................. 100 Chapter 3. Self-reference on past performance and firm risk as predictors of lean production implementation ................................................................................. 113 Table 3.1. Industry distribution of the sample and the population ........................ 127 Table 3.2. The implementation of lean production construct ................................ 129 Table 3.3. Past operational performance ............................................................... 131 Table 3.4. Means, standard deviations and Pearson correlations coefficients ....... 132 Table 3.5. Results of the regression analyses on implementation of lean production134 Table 3.6. Results of the regression analyses for Hypothesis 3 ............................. 134 Figures index Chapter 1. Lean production and human resources: A systematic literature review ...................................................................................................................... 18 Figure 1.1. Article selection process ........................................................................ 30 Chapter 2. Lean production, workforce development and operational performance ........................................................................................................... 77 Figure 2.1.The graphical depiction of the hypotheses ............................................. 88 Figure 2.2. Graphical depiction of the results ........................................................ 100 Chapter 3. Self-reference on past performance and firm risk as predictors of lean production implementation ................................................................................. 113 Figure 3.1. The hypothesized model of the paper.................................................. 125 - 1 - INTRODUCTION - 2 - INTRODUCTION Present doctoral thesis has the intent to make an impact via the identification of a number of internal and external factors in the environment of the company, which contribute to the explanation and extend the comprehension with respect to the implementation process of lean production in manufacturing firms. This novel understanding is deduced from the employment of an empirical analysis carried out among companies pertaining to the first tier suppliers of the Spanish automotive industry as well inferences based on a systematic analysis of the available literature on the subject are presented. This is the introductory part of present doctoral dissertation that sets out the content through the adoption of a holistic approach for this purpose. The Introduction is structured into three interconnected parts. Firstly, a comprehensive explanation is provided with reference to the background of lean production. This way, it is hoped that an understanding is acquired by setting out the origins of this managerial system and unfolding the evolution of the concept of lean production as well as putting an emphasis on its expansion into different sectors of the economy. The second part revolves around the underlying motivation that finally led to the endeavor of undertaking this research. In the face of this, the objectives that were being sought and the research questions that the different chapters attempted to provide an answer are to be set out in this section. The methodological approaches that were resorted to are outlined to a detailed extent in the third part of the introduction. Finally, the overall structure of this thesis is discussed in the last part that also handles the content of the upcoming chapters, such as the main objectives and findings of each of them. - 3 - I. Background of the research This part of the introduction chapter aims to provide an insight on the subject of the investigation with respect to lean production. Therefore, the birth of the concept of lean production is explained. The motivation for writing the thesis is set out as well, which is then followed by the objectives that were investigated and explored. I.I The origins and evolution of lean production The scientific literature usually describes lean production as a management system, which is based on the Toyota Production System or TPS (Holweg, 2007). The set of tools, which comprises said practices, was first used in the Japanese manufacturing industry and the term itself was devised by Krafcik (1988) in his article Triumph of the Lean Production System that was based on his master's thesis. As a continuation of his research with the goal of obtaining a better understanding about the challenges of the global automotive industry, Womack et al. (1990) enclosed their findings with the public in their international best-seller called The Machine That Changed the World. The ideas of the book were based on a five-year research with the aim of obtaining information about the future of the automobile industry under the framework of their project called International Motor Vehicle Program at the MIT. Their investigation is considered a milestone in the operations management (OP) research ever since, as in the book it is distinguished between traditional mass production systems and lean production. Owning to Holweg (2007), the novel contribution of the Machine that Changed the World lays in the identification of key differences between lean production and the traditional mass production systems of the Western world that was prevalent at that time. Empirical evidence was provided to demonstrate that companies that implemented - 4 - the concept of lean production could produce considerably improved results as compared to the other type of mass production system. In addition, lean firms were observed to possess an enhanced ability in retaining their competitive edge. The most salient idea of the book comprised the fact that lean production is not only transferable to other organizations but that the concept can also be adapted in different sectors of the industry other than the automotive industry. In order to create a tangible concept of lean production, the following simplification can be used based on the above. Lean production makes use of the concept learning organization and continuous improvement. With other words, a value stream for a given manufacturing process is created and then continuously improved as a way to achieve perfection. This is done by putting the whole system under investigation. Once an imperfection is identified, there is a plethora of disposable lean tools and techniques to make up for the error and improve the overall production process. Since the establishment of the foundations on lean production research by Krafcik (1988) and Womack et al. (1990), there has been a spate of research into this particularly salient field of study. This research interest is a result of the complex environment and new challenges due to global competition in the industrial scene. In this context, the capability of manufacturing firms to preserve their competitive advantage has become more difficult, therefore they were compelled to adapt new manufacturing approaches, which are more oriented toward customer needs (Negrão et al., 2016). Among them, the most salient concept was lean production. Since the original researchers devised the term of lean production, a myriad of its aspects were subject to investigative scrutiny, which can be divided into two main epochs. In the 1990s, researchers usually focused on the “hard side” of the implementation of lean production. This included attention paid to technical details. Later, owning to the recurring number - 5 - of failures, this focus turned to the “soft side” that addressed people-related phenomena as well, as the integration of the hard and soft sides was deemed crucial (Sawhney and Chason 2005). Nowadays, there is an agreement among scholars that the concept of lean production can be described as a set of philosophical tools (Moyano-Fuentes et al., 2012), which is in a state of continuous evolution and encompasses all levels of the organization (Womack and Jones 1996). The set of integrated socio-technical principles that comprises lean production aims to minimize all sources of internal and external system variability to the lowest extent (Shah and Ward 2007), that is, driving out any unnecessary expenses, which do not contribute to the creation of value (Zhou, 2016). Though the concept itself originates from the automobile industry, there has been a clear trend toward its adoption in different sectors of the industry as well (Shetty et al., 2010), such as the aeronautic industry and health care. In lean production research, the positive contribution of human resources and their management is relatively well established: employees’ motivation, their level of knowledge and skills are factors that are indispensable if a company opts for the implementation of lean production (Macduffie, 1995). Human resources can help provide employees with training, and thus, obtain the required sets of skills that can come handy when the transformation is made from a traditional production culture to lean production. Besides the above, there are papers that establish the role of the geographic context that companies operate in during the adoption and implementation of lean production, however, it has not been studied how it affects other aspects related to the variability of the environment in the implementation of lean production. Notwithstanding, it should be pointed out that most of the papers in lean production research have a focus on scrutinizing the adoption and implementation processes of lean production at the last level of the supply chain of the related industrial - 6 - sectors (automobile and aircraft manufacturers). The implementation process of lean production in the remaining levels of the supply chain has received far less research attention with the notable exception of Moyano-Fuentes and Sacristán-Díaz (2012). This way, the importance of putting first tier suppliers of aforementioned industries into investigation is important. I.II. Motivation of the doctoral dissertation and its main objectives In the setting of lean production, the implementation process brings about a significant change in the organizational structure of the company where failure was observed to be an inherent danger, with special regards to the initial stage of the transition process (Martínez-Jurado et al., 2014).This puzzling situation has led researchers to turn to the investigation of human resources and their management in lean production. This area is connected to the principles of lean production to a great extent given that the human factor and respect for people build a central aspect of lean production (Emiliani, 2007). Companies usually opt for the implementation of lean production because they hope to achieve improved outcomes for their respective firms (Romano et al., 2010). In reality, however, there is compelling evidence that suggests that in case of a number of manufacturing firms and companies in the service sector, the implementation of lean production was not associated with more desirable results, thus the process resulted in a failure. The literature points out that the transformation to lean production is a complex process whereby the company needs the deal with a great variety of obstacles (Scherrer- Rathje et al., 2009). Therefore and owning to the lack of consensus with respect to factors that countribute to a successful outcome in terms of the implementation of lean production, researchers have been calling for renewed scientific scrutiny and more sophisticated research as to reveal the reason of why some companies do not manage to - 7 - obtain the enhanced outcomes associated with the implementation of lean production. Failures are usually linked to the lack of attention to the human element and the inability of the company to manage their changing internal and external environment. With respect to the human element, its crucial importance has been in the crossfire of research interest since the second half of the 1990s. More precisely, researches turned to the investigation of human resources and their management after they had realized that besides the hard sides of the implementation, there are other aspects to consider (Bonavía and Marín-García, 2011), given the pivotal role of the workforce in the wake of a significant organizational and cultural change (Martínez- Jurado et al., 2013). As lean production is usually associated with improved performance, managers were seen to opt for its implementation with the aim of obtaining a better position with respect to competitors (Tsai and Luan, 2016). Similarly, one of the underlying characteristics of lean production is that it deals with the variability of the external and internal environment (Shah and Ward, 2007). So far, however, research has mainly focused on either the internal or the external variability. Addressing both sources of system variability may facilitate the decision-making process of managers and contribute to the comprehension of success factors with respect to the implementation of lean production. For all the above reasoning, present dissertation analyzes the role of internal and external changes, which are brought about by the implementation of lean production. The thesis revolves around two different types of environmental variability that influence the way managers make their decisions and therefore have pivotal inferences for both practitioners and scholars. On the one hand, the research takes into account the role of the variability of the environment in the implementation of lean production - 8 - (through firm risk) and on the other hand, the role of internal changes (variability in performance indicators) in the implementation of lean production. This way, the introduction of lean production has an impact on workers (internal change) and, ultimately, the operational outcomes of the company are also affected. In this sense, this research studies how managers’ decision-making process is influenced in the implementation of lean production and shows that decisions are adopted to reduce the variability of the environment of the company (that is a result of the advancements in the implementation of lean). This achieved by accounting for both: 1) changes in factors that are not directly controllable by them (firm risk) and 2) changes with respect to internal factors linked to the operational outcomes of the companies that are in fact controllable by the managers. In the same vein, the thesis investigates the changes that are triggered internally by the implementation of lean production studying the impact it generates on the most prominent element of the lean principles, human resources, more specifically, the development of the workforce. Precisely, the importance of human resources in the implementation of lean production is what motivated an exhaustive review of the literature on the role of human resources in the implementation and consolidation process of lean by proposing a novel classification of the literature and which resulted in the identification of gaps and research challenges that should be addressed in a future occasion. This doctoral dissertation attempts to address the aforementioned gaps by conducting research in the field of lean production and driving forward our comprehension on the subject of this management system. The thesis employs a - 9 - theoretical and empirical perspective and puts its emphasis on the implementation phase, the initial stage of lean production. More specifically, this serves to make up for the lesser amount of attention that is paid to this primary period of lean production. The underlying aim of taking advantage of such an approach lies in the potential identification of key factors that contribute to the understanding of success factors of the lean production implementation. This then can be made use of by managers and help obtain the improved outcomes associated with lean production. The above explained factors of the research approach follow a strategic and a holistic point of view that reflects on the automotive industry in Spain. This investigation, however, has a different approach compared to the majority of the articles in this field, since the main focus is put on the first tier suppliers in the supply chain and not on the original equipment manufacturers. It has been set as an aim of this dissertation to analyze the role of these factors with respect to the implementation of lean production. From the point of view of the management, this analysis accounts for both the directly controllable factors and those that are out of reach of the managers. In addition, a special emphasis is provided to the soft side of the implementation of lean production. In this light, the crucial impact of human resources and their management has been given a special focus in order to determine its contribution to the successful outcome of the implementation process and its connection with the hard side of lean production. The specific objectives of present doctoral dissertation can be broken down as the following: - 10 - 1) To provide a systematic analysis of the available scientific literature on the field of lean production and human resources and their management with the aim of achieving the following main objectives:  To identify criteria that contribute to the establishment of novel classification of the literature.  To acquire the ability to group the literature into lines of research in the framework of the proposed classification.  To discuss the disposable empirical evidence on the subject and to propose new research directions based on the spots where gaps were identified for future investigation purposes and for researchers who want to delve into this topic. 2) To scrutinize the role of workforce development in the automotive industry and the way it contributes to the attainment of higher operational outcomes while concurrently facilitates the adoption of lean production in order to comply with the following goals:  To acknowledge the role of workforce development and its related practices as a success factor in the implementation phase of lean production.  To propose that workforce development and its practices contribute to the achievement of obtaining enhanced performance outcomes when they are taken advantage of in a manufacturing firm that has implemented lean production to a certain degree. 3) To expand the knowledge about how the environment, in which the company operates influences the process of the implementation of lean production, and facilitate the decision-making of managers when they want to deal with the - 11 - variability of the external and internal environment in the same time with the aim of providing coverage for the research objectives below:  To identify the contribution of changes with respect to internal factors linked to the operational outcomes of the companies that are in fact controllable by the managers.  To identify factors that managers do not have direct control of and their contribution of the change in these factors from the point of view of the implementation of lean production. II. Methodological approaches An in-depth literature review was carried out with the aim of complying with the first objective of the dissertation. The first aim was to carry out a systematic analysis of the literature on the field of lean production and human resources and their management and structure them into lines of research while concurrently gaps are identified. A systematic literature review (SLR) is considered to be a crucial step in structuring a field of study. In addition, it can enhance researchers’ comprehension, facilitate the theoretical progress via developing theories, enable the deduction of progress by research and help new researchers who want to delve into this area, identify the contradictions and gaps pertaining to the literature. This reasoning provided the base of taking such a course of action. Empirical research was employed in case of the second and the third objectives. This method corresponds to a systematical empirical investigation that aims to scrutinize observable phenomena through statistical techniques. The main goal of such an analysis is to contrast theoretical reasoning with statistical models. It is the process of - 12 - measurement that provides the fundamental connection with the empirical observation with the help of statistical tools (Given, 2008). Given the fact that in social sciences, quantitative method is the most prevalent way of making inferences, it was decided that this dissertation also employed aforementioned methodology to provide an answer to second and third the research objectives. One of the main advantages of the employment of such an approach is that it yields a resolution to a narrow line of research. A contra for using this methodology lies in the fact that given the narrow scope of research, any generalization based on the sample of the research with respect to the population as a whole is hypothetic in nature. Data collection was carried out among the first tier suppliers of original equipment manufacturers that covered the entire Spanish automobile industry. For the purpose of collecting information about this sector, a questionnaire was developed which was then sent out to the manufacturing firms. Means of dissemination included conventional postal delivery services and e-mail. Among the informants one can find CEOs of the companies, heads of the human management department and directors of production and operations department. The population comprised a total of 216 that were derived from the database of SERNAUTO. In total, 84 duly completed surveys were sent back. The possibility of learning about the motives of companies that did not return a questionnaire arose, however, it was not possible to deduce a specific pattern to explain why some companies refused to answer. It was determined that the geographical distribution of the plants in the sample falls in line with the actual distribution of the population as a whole. The received questionnaires were evaluated and processed so that they could be used for the scientific purposes set out in the dissertation. The relevance of the automotive sector for research purposes is axiomatic and lies in the fact that this industrial sector has always been the most receptive for the - 13 - implementation of lean production. In addition, the original Toyota Production System was also employed in the setting of the automotive sector. More specifically, as the theoretical foundations of lean production in this industry are already relatively well- established, it provides the opportunity to build upon them and push forward the boundaries of this field of study. In addition, given the aforementioned context, there is no need to carry out explanatory research, for instance in the form of a case study, as this methodology is more relevant for sectors that have recently become subjects to scientific scrutiny. Notwithstanding, this thesis had the opportunity to put its focus on the process of the implementation of lean production itself in case of companies that had adopted this kind of management system to different degrees. During the conduction of the research, primary and secondary data sources were made use of as well. The main source of the primary data was based on the questionnaire, which was introduced afore. The Iberian Balance Sheet Analysis System (SABI) database served as a complementary database that was used to obtain financial and economic data about the manufacturing plants that took part in the research. The different methodological specialties are explained to a greater degree in the corresponding chapters with the aim of achieve the research objectives stated in the previous part of this introduction. III. Structure of the thesis This doctoral thesis features three chapters, which address the three main research objectives outlined in the previous part. The first chapter provides a systematic literature review with respect to lean production and human resources and their management. The reason of undertaking the - 14 - research in concern was to structure the available literature into distinguishable lines of research, reveal gaps and come up with challenges for future research in the field related to human resources and their management and help future researchers to engage with this field of study. The proposed lines of research facilitate the comprehension of researchers and practitioners on the subject of lean production and its success factors. The second chapter handles the role of workforce development in the initial stages of the adoption of lean production and its impact on the degree of the implementation of lean production and their impact on operational performance. One of the contributions is that workforce development should be given focus in the same time when the company opts to advance to a further degree in the adoption of lean production. The third chapter revolves around the subjects of self-reference on past performance and firm risk. These are external and internal factors that are either controllable by managers of a company or out of their reach. These aspects, however, have a crucial role especially in the implementation of lean production and are, therefore, important. The research questions in this chapter are answered via a set of hierarchical regression analyses. The main contribution of this chapter is that it helps managers undertake difficult strategic decisions in a sense that they take into account the level of risk of the environment when making decisions related to carrying out advancements in the implementation of lean production. Managers need to consider not only those factors that are controllable by them, but they should also be aware of those aspects that are out of their reach and can therefore not deal with them. To conclude, each of the following three chapters begin with an introduction part, which outlines the motivation for conducting the research and the gaps that - 15 - provided the opportunity for undertaking the investigative study. The section in concern also points out the research question at the beginning of each chapter. Then it is proceeded to the establishment of the theoretical framework that is developed with the aim of providing a background for the hypotheses of the subsequent sections. This is then followed by the methodological part, which serves the aim of providing a resolution to the initial research question. The findings are then outlined in the part where the results are shown and then discussed in the conclusion. The conclusion also handles the theoretical and practical contribution of each chapter and provides future lines of research for researchers who would like to immerse in the given topic. Finally, bibliographical references appear at the end of each chapter, but the references cited at the end of each chapter pertain to that specific chapter in concern. Figures, tables as well as footnotes are numbered separately for each of the chapters. This results in the numbering of them not following on from one chapter to another. IV. References Bonavía, T. and Marin-García, J. A. (2011): Integrating human resource management into lean production and their impact on organizational performance. International Journal of Manpower, 11, pp. 923–938. Emiliani, M.L. (2007): Understand the Lean Management System. Vol. 1, Center for Lean Business Management, Wethersfield, CT. Given, L.M. (2008): The SAGE Encyclopedia of Qualitative Research Methods. SAGE Publication, Los Angeles, USA. Holweg, M. (2007): The genealogy of lean production. Journal of Operations Management, 25 (2), pp. 420–437. - 16 - Krafcik, J.F. (1988): Triumph of the lean production system. Sloan Management Review, 30 (1), pp. 41-52. Macduffie, J.P. (1995): Human Resource Bundles and Manufacturing Performance: Organizational Logic and Flexible Production Systems in the World Auto Industry. Industrial and Labor Relations Review, 48 (2), pp. 197-221. Martínez-Jurado, P., Moyano-Fuentes, J. and Jerez-Gómez, P. (2013): HR management during lean production adoption. Management decision, 51 (4), pp. 742-760. Martínez-Jurado, P., Moyano-Fuentes, J. and Jerez-Gómez, P. (2014): Human resource management in Lean Production adoption and implementation process: Success factors in the aeronautics industry. Business Research Quarterly, 17 (1), pp. 47–68. Moyano-Fuentes, J. and Sacristán-Díaz, M. (2012): Learning on lean: a review of thinking and research. International Journal of Production Management, 32 (5), pp. 551-582. Moyano-Fuentes, J., Martínez-Jurado, P. J. and Maqueira-Marín, J. M., Bruque-Cámara, S. (2012): Impact of use of information technology on lean production adoption: Evidence from the automotive industry. International Journal of Technology Management, 57, pp. 132-148. Murman, E., Allen, T., Bozdogan, K., Cutcher-Gershenfeld, J., McManus, H., Nightingales, D., Rebentisch, E., Shields, T., Stahl, F., Walton, M., Warmkessel, J., Weiss, S. and Windnall, S. (2002): Lean Enterprise Value: Insights from MIT’S Lean Aerospace Initiative. Palgrave Macmillan, New York, NY. Negrão, L.L., Filho, M.G. and Marodin, G. (2016): Lean practices and their effect on performance: a literature review. Production Planning & Control, 28 (1), pp. 33-56. - 17 - Sawhney, R. and Chason, S. (2005): Human behavior based exploratory model for successful implementation of lean enterprise. Performance Improvement Quarterly, 18 (2), pp. 76-96. Romano, P., Danese, P and Bortolotti, T. (2010): The Moderating Role of JIT Links with Suppliers on the Relationship between Lean Manufacturing and Operational Performances. In: Vallespir B., Alix T. (eds.): Advances in Production Management Systems. New Challenges, New Approaches. APMS 2009. IFIP Advances in Information and Communication Technology, vol 338. Springer, Berlin, Heidelberg Scherrer-Rathje, M., Boyle, T.A. and Deflorin, P. (2009): Lean, take two! Reflections from the second attempt at lean implementation. Business Horizons, 52 (1), pp. 79–88. Shah, R. and Ward, P.T. (2007): Defining and developing measures of lean production. Journal of Operations Management, 25, pp. 785–805. Shetty, D., Ali, A. and Cummings, R. (2010): Survey-based spreadsheet model on lean implementation. International Journal of Lean Six Sigma, 1 (4), pp. 310-334. Tsai, H.F. and Luan, C.J. (2016): What makes firms embrace risks? A risk-taking capability perspective. Business Research Quarterly, 19, pp. 219-231. Womack, J.P. and Jones, D.T. (1996): Lean Thinking. Simon & Schuster, New York, NY. Womack, J.P., Jones, D.T. and Ross, D. (1990): The Machine that Changed the World. MacMillan/Rawson Associates, New York. Zhou, B. (2016: Lean principles, practices, and impacts: a study on small and medium- sized enterprises (SMEs). Annals of Operations Research, 241 (1), pp. 457-474. - 18 - CHAPTER 1. - 19 - LEAN PRODUCTION AND HUMAN RESOURCES: A SYSTEMATIC LITERATURE REVIEW 1.1. Introduction In the last three decades, the industrial scene has faced novel challenges stemming from increased global competition (Wickramasinghe and Wickramasinghe, 2016) which caused operations and supply chains to grow in complexity at an unparalleled rate (Hu et al., 2008). In such a transitional environment (McAllaster, 2004), companies are compelled to implement a great number of changes in their operations in order to compete in dynamic markets (Noll, 2000). Consequently, companies have been looking at new ways to improve their business operations in order to remain profitable (Cauchick and Monteiro, 2014). As a result, such conditions have given rise to new manufacturing approaches (Hall, 1987), which are more oriented towards efficiency by eliminating internal and external sources of variability (Shah and Ward, 2003). In order for companies to retain their competitive edge, manufacturing firms have been prompted to adopt the particularly salient concept of lean production (Womack and Jones, 1996). Recent days, lean production is considered to be a paragon for production optimization and a toolset for survival in a competitive global environment (Anvari et al., 2011). The multi-dimensional approach of lean production (Shah and Ward, 2003) comprises a complex set of manufacturing principles, which aims at streamlining the flow of production (Smith and Synowka, 2014), while the concept itself is based on continuous improvement (Womack et al., 1990) in eliminating any kind of waste (Shah and Ward, 2007). This turns the main focus to efficiency, while wipes away any kind of - 20 - bottlenecks (Hines, 2004). Subsequently, a number of companies from different industrial areas have been contemplating the implementation of lean production (Shetty et al., 2010). To sum up, Shah and Ward (2007, pp. 791) proposed the following the widely accepted definition of lean production which is also employed in present paper. “Lean production is an integrated sociotechnical system whose main objective is to eliminate waste by concurrently reducing or minimizing supplier, customer, and internal variability.” In this sense, machinery and equipment should be highly automated and computer controlled, while human resources should be flexible and cross-functional to be able to operate the state-of-the-art machinery and also receptive to change and learn new approaches (Singh and Chauhan, 2013). Despite the fact that the use of lean production by manufacturing companies started in the late 1980s, only a couple of them reached a truly lean system (Anvari et al., 2010). This was puzzling not only for managers but for researchers as well. Prior to the 1990s, the primary focus of research scrutiny was related to the technical aspects of the implementation of lean production (Bonavía and Marin-García, 2011). Later, owning to the recurring failures of the implementation this kind attention shifted to include people-related phenomena as well (Emiliani, 2007b; Martínez-Jurado et al., 2013). Therefore, the understanding of how people relate to conditions in a lean environment has become an important success factor (Tortorella and Fogliatto, 2014). This new research direction was somewhat expected to emerge given that the human factor and respect for people builds a central aspect of lean production (Emiliani, 2007a; Moyano- Fuentes and Sacristán-Díaz, 2012). While lean principles have obvious ramifications for human resources and their management, the linkages between the two areas are not clearly established in the literature as well as in practice. Nonetheless, it has been argued that lean production - 21 - systems presuppose certain human resource management practices (Appelbaum et al., 2000). On the other hand, as a result of the human resources being strongly embedded in the national local context, standardization in this respect could face a number of difficulties (Jürgens and Krzywdzinski, 2013). More specifically, Engström et al. (1996) contend that the successful implementation of lean production in Japan can be attributed to the favorable conjunction of the socio-economic and socio-cultural circumstances. Another aspect, the role of work organization is underscored by Moyano-Fuentes and Sacristán-Díaz (2012) as an outstanding line of research on lean production. Nonetheless, a number of investigations unveil negative connotations of lean production when addressing human resources concurrently. More particularly, due to the fact that work becomes more intense after the implementation of lean production, workers receive a higher dose of stress (Fairris and Tohyama, 2002), while the monotonous and repetitive working conditions (Schouteten and Benders, 2004). These count towards the unfavorable effects of lean production on human resources (Moyano-Fuentes and Sacristán-Díaz, 2012). The existent literature reports that nine out of the ten top barriers to lean production transformation are people-related (Tortorella et al., 2015), including poor communication and employee’s resistance to change (Bhasin, 2012; Shook, 2010). Some authors suggested that dealing with such barriers involves implementing changes in organizational culture (Sawhney and Chason, 2005). However, existing organizational cultural status quo might be a barrier in itself (Sim and Rogers, 2009). Therefore, one of the key points for a successful transformation is the understanding of how people and organizations perceive changes when exposed to a transitional environment. In this light, Tortorella and Fogliatto (2014) make mention of a set of intangible components, such as the emotional state of employees. Consequently, there is - 22 - a spate of research that deals with the one or more aspects of human resources and their management in the implementation and consolidation phase of lean production. For this reason, the need has emerged for the organization of this scrutiny into distinguishable lines of research based on a guiding principle that takes into account previous empirical and theoretical articles of this field by carrying out an adequately sophisticated literature review. In the past couple of decades, a number of explanatory research articles have attempted to put the role of human resources and their management in the early phases of lean production implementation under investigation. Recently, Stone (2012) analyzed and identified the phases of lean production research stemming from the inception of the concept. Concurrently, via incorporation of a significant number of related research articles, Bhamu and Sangwan (2014) contributed to the investigation of differences between the definitions of lean production in various papers and established the typical profile in lean production research. Beauvallet and Houy (2010) recognized the role of human resources management in the implementation and consolidation period of lean production in their literature survey and they combined knowledge about the two areas. These studies have only contributed to a certain extent to the comprehension concerning human resources in the early phases of lean production. For instance, Alagaraja (2014) focused solely on success factors and barriers to the implementation and sustainability of lean production from a human resources point of view. There is a similarity among these previous papers in a sense that they took a specialized and partial approach on the relation between human resources and lean production. Present study, however, is different because of the segmentation of the research carried out with respect to the role of human resources in the implementation and consolidation phases of lean production. - 23 - Consequently, on the basis of the above reasoning, the main objective of this paper is to identify lines of research on the subject of the role of human resources and their management in the context of the implementation and consolidation of lean production. It is hoped that the widely available but fragmented pieces of literature can be pulled together efficiently so that it amplifies the ability of academics and practitioners to understand the role of human resources in the crucial early stages of lean production implementation. More importantly, light can be shed on the impact of human resources and their management a posteriori the initial introduction of lean production once the company has decided to take further steps in the implementation and consolidation process. This would allow the deduction of progress by the research, facilitate the work of new researchers who want to delve into this area, identify the contradictions and inconsistencies existent in the literature and specify the gaps or aspects of literature where further research is required. This paper focuses on both human resources and human resources management because they are closely related to the human factor and respect for people, some of the major principles of lean production (Emiliani, 2007a, b; Moyano-Fuentes and Sacristán-Díaz, 2012). To provide an exhaustive answer to the research question, present paper is structured into four parts, with this first part devoted to introduction. The second section sets out the methodology employed in this paper. Subsequently, section 3 outlines the results of the systematic literature review, while the fourth section concludes that paper and highlights its main implications. - 24 - 1.2. Methodology This paper applies the systematic literature review approach and employs this methodology used by other researchers for related purposes (Stone, 2012; Martínez- Jurado and Moyano-Fuentes, 2014a, b). The role of human resources and their management in the implementation and consolidation process of lean production is an emerging aspect of this field. This mainly owns to the fact that the majority of the research articles have a focus on the technological aspects of lean production (Bonavia and Marin–García, 2011). In the meanwhile, researchers were called for more scrutiny in terms of the role of human resources in the adoption and implementation processes of lean production (Martínez–Jurado et al., 2013). Previous articles that have intended to link human resources and lean production have focused on narrow and partial aspects of the existing connections between the two areas. Thus, a comprehensive literature review carried out in a sophisticated and systematic manner would enhance the comprehension about the role of human resources in the implementation and consolidation process of lean production. For this reason, an in-depth evaluation was carried out of the relationship in the literature between lean production and human resources. A literature review can facilitate structuring a field of research, the development of theories and contribute to advances in knowledge (Martínez–Jurado and Moyano–Fuentes, 2014b). In addition, a systematic literature review may be of crucial importance for policy makers and academics (Tranfield et al. 2003). Principles regarding the mechanics of a systematic literature review were sophisticatedly outlined by Tranfield et al. (2003). Present paper follows the guidelines set out by above researchers. First of all, the article should contain a section that explains the methodology (Greenhalgh, 1997) with the aim of avoiding biases (Mohrer - 25 - et al., 1995). This is achieved by providing the description of methods used for data collection and analysis. Then, a systematic literature review should aim to create a synthetized outcome so that the study acquires a holistic nature. The product, however, differs from a traditional literature review in a sense that that the final outcome is likely to become a synthesis of the literature that explores the main lines of research and reveals areas in the literature that require to be subject to further scientific attention (Denyer and Tranfield, 2009). 1.2.1 Research design The following section summarizes the measures taken to obtain the final set of papers considered in the systematic literature review (Martínez-Jurado and Moyano-Fuentes, 2014a, b; Durach et al,. 2014). In this light, the first step was to determine the locations of the most prominent papers. For this reason, two steps were carried out. Firstly, a pool of databases with the most significant pieces of literature had to be identified. The selected databases were ABI/Inform Complete, Scopus and ScienceDirect. These portals were chosen as they have some of the largest repositories of business research and are typically used in literature reviews (Carter and Easton, 2011). The publication of The machine that changed the world (Womack et al., 1990) marked the starting point of the time frame of this paper. Therefore, the search was limited to articles published between January 1, 1990 and October 31, 2016 to cover a period of 26 years. The bibliography included peer reviewed articles and paradigmatic books strongly related to the subject area of human resources and lean production. Dissertations, unpublished working papers as well as conference proceedings were excluded (Table 1.1). - 26 - Table 1.1. Main characteristics of the methodological approach Unit of analysis Research articles and prominent books with managerial impact that handle the linkages between lean production and human resources. Type of analysis Qualitative research. Period of analysis January 1, 1990 – October 31, 2016. The keywords were determined after a careful examination of the literature. Keywords were selected based on the frequency they were used in the studies with the aim of selecting those which accounted for the highest number of occurrences (Martínez-Jurado and Moyano-Fuentes, 2014a, b) (Table 1.2). The final set of literature for the review was compiled in October 2016 to cover a period 26 years. Table 1.2. Keywords employed in the searches conducted Lean management Human resources Lean, Lean management, Lean production, Lean manufacturing, Lean production systems, Lean production implementation, Toyota Production System, TPS, Six sigma Human resource, Human resources, Human resource management, HR, HRM, Blue collars, People, Workers The keywords were then combined to construct various search strings which were employed in the database survey. Building upon Seuring and Gold (2012), this paper employed the following search strings (Table 1.3). As an additional criterion, with the aim of increasing the quality of the systematic literature review, the authors resorted - 27 - to articles that are registered in operations management journals from the Journal Citation Reports (JCR) published annually by Thomson Reuters. No further criteria were applied to carry out the search. Table 1.3. Search strings for database search Scopus TITLE-ABS-KEY ( "lean production" OR "lean management" OR "lean manufacturing" ) AND TITLE-ABS-KEY ( "human resources" ) AND DOCTYPE ( ar ) AND SUBJAREA ( mult OR arts OR busi OR deci OR econ OR psyc OR soci ) AND PUBYEAR > 1990 AND ( LIMIT-TO ( LANGUAGE , "English" ) ) ScienceDirect ABI/Inform Complete TITLE-ABSTR-KEY("lean management" OR "lean production") and TITLE-ABSTR-KEY("human resources" OR "human resource")[All Sources(Business, Management and Accounting)] all("lean management" OR "lean production" OR "lean manufacturing") AND all(("human resource" OR "human resources")) – Additional limits: Date: From January 01 1990 to October 31 2016; Language: English The literature survey conducted based on the aforementioned methodology yielded a total of 871 articles. Despite the different search approaches, the searches provided a number of overlapping results that can be seen as an indication for substantial consistency of the search strings. After the incipient complication of papers was obtained, the first step was the elimination of the duplicates. This left 792 articles. - 28 - The raw sample was then manually searched for any irrelevant articles. For this purpose, a random subset of 20 titles and abstracts was created with the name of the author(s) and the year of publication being concealed. This subset was then read independently by the authors to identify inclusion criteria. Subsequently, all the articles were screened and assessed based on the carefully established criteria through reading the titles and abstracts. This step was necessary to ensure that the main contribution of the papers revolved around the association between human resources management and lean production. Whenever disagreement occurred due to the information provided in the abstract or in the title not being sufficient to decide on their inclusion, the authors resorted to read the full paper instead. The inclusion criteria served as a refinement to increase the robustness of the electronic search strings in the three online databases and to make certain that the articles are within the framework of this study. The insight of the authors corroborates the viability of the inclusion criteria set up by Durach et al. (2014) (Table 1.4). The above-explained analysis led to the inclusion of 74 articles (Figure 1.1). In the subsequent step, the set of articles was surveyed as to produce a classification based on their main contribution with the aim of grouping them according to lines of research. In this procedure, the following actions were undertaken individually by the researchers. First, the researchers of this paper analyzed the research question of each article with the aim of coming up with the key characteristics pertaining to human resources management and lean production. Then, these key aspects were grouped on the basis of similarities and/or relatedness. Finally, owning to the results of the previous steps, lines of research were proposed. The insights obtained independently as a result of this process were then pooled and resolved jointly by the authors to establish the classification of the corresponding literature into lines of research that is detailed in the upcoming section of this paper. - 29 - Table 1.4. Inclusion criteria Criteria Rationale 1. The title and/or abstract make an explicit mention of lean production and human resources. Some authors deliver their studies in the area of lean production or human resources but the two fields are not unconnected in the research. 2. The primary focus is on the analysis of human resources in the theoretical or empirical environment of lean production. The authors present either a theoretical or a research paper with the emphasis being on the aspects of human resources in a lean environment. Studies using HR practices unrelated to lean production are out of the scope of this research. 3. The title and/or abstract demonstrate that the authors conduct research in the area of lean production. Since present research is not restricted to specific journals, articles must conduct lean production related research instead of just mentioning the term and be published in a peer- reviewed journal. 4. The article is written in English. Due to the fact that journals with the highest impact factor are exclusively in English, enacting this criterion may ensure the high quality of the sample. - 30 - Figure 1.1. Article selection process 1.3. Results and discussion The above-mentioned procedure allowed the identification of four major research topics anchored in the interrelationships of human resources and their management and lean production. These research lines can be set out by taking advantage of the following grouping into lines of research: 1) Socio-cultural factors, 2) Work organization, 3) Trade unions, and 4) Knowledgeable workforce and participative management. Table 1.5 sets out this proposed classification with the list of articles that were ascribed to each of the suggested lines of research in alphabetical order. Given the multidimensional point of view of lean production, it should be noted that some of the articles appear under more than one category since a given study may have connections with socio-cultural factors while concurrently may be pertinent to trade unions as well. Appendix 1 provides a brief summary of each of the papers included in the analysis. The following section addresses each of the lines of research to a detailed extent. Special emphasis is placed on inconsistencies and contradictions that were detected during the execution of this systematic literature review. Locating articles (871) ------------ Database searches in Scoupus, ScienceDirect and ABI/Inform Complete Eliminating duplicates (792) ------------ Elimination of duplicates from the database searches Article selection (74) ------------ Eliminaton of papers that did not meet the inclusion criteria - 31 - Table 1.5. Literature classification Line of research Main articles Socio-cultural factors Adler (1993); James and Jones (2014); Lee and Peccei (2008); Lewchuck et al. (2001); Liker (2004); Lincoln and Kalleberg (1990); Lowe et al. (1997); Moreno (1999); Niepce and Molleman (1996, 1998); Oliver et al. (1994, 1996); Portioli and Tatardini (2008); Salaheldin (2005); Saruta (2006); Scherrer-Rathje et al. (2009); Shah and Ward (2003); Smith et al. (2003); Spithoven (2001) Work organization Anand and Kodali (2010); Angelis and Fernandes (2012); Barton and Delbridge (2006); Birdi et al. (2008); Brkic and Tomic (2016); Conti et al. (2006); de Menezes et al. (2010); Delbridge et al. (2000); Doolen et al. (2008); Dubey and Singh (2015); Friedrich et al. (2016); Furlan et al. (2011); Hiltrop (1992); Jones et al. (2013); Khalaf et al. (2011); Kim et al. (2002); MacDuffie (1995); Marksberry (2010); Martínez-Jurado et al. (2013; 2014); Niepce and Molleman (1998); Pakdil and Leonard (2014); Pil and MacDuffie (1995); Procter and Radnor (2014); Rodríguez et al. (2016); Shaiken et al. (1997); Tortella and Fogliatto (2014); Wickramasinghe and Wickramasinghe (2016); Womack et al. (1990) - 32 - Trade unions Ahmed et al. (1991); Clardy (1999); Delery (1999); Dong and Bae (2005); Lee (2003); Lee (2004); Lewchuck et al. (2001); Martínez- Jurado et al. (2014); Shah and Ward (2003) Knowledgeable workforce and participative management Bonavía and Marin-García (2011); de Koeijer (2014); Drew et al. (2004); Emiliani (2007a); Emiliani (2007b); Emiliani (2008a); Emiliani (2008b); Gollan et al. (2015); Gupta et al. (2013); Jabbour et al. (2013); Jürgens and Krzywdzinski (2013); Kim et al. (2002); Liker and Hoseus (2010); Lindsay et al. (2014); Longoni and Cagliano (2015); Meiling et al. (2012); Morrison (2015); Nepal et al. (2011); Niepce and Molleman, (1996); Paez et al. (2004); Rane et al. (2016); Sawhney and Chason (2005); Scherrer-Rathje et al. (2009); Shadur et al. (1995); Sohal and Egglestone (1994); Tortella et al. (2015); Wickramasinghe and Wickramasinghe, (2016); Yang and Yang (2013) 1.3.1. The role of socio-cultural factors in the implementation and consolidation of lean production The production system of Toyota, lean production, enjoys a great deal of attention on behalf of managers and is implemented worldwide. However, notable advancements are first achieved and exploited in Japan. It is only then when these new principles are transferred to different parts of the world (Saruta, 2006). This results in a perplexing situation provided that “foreign affiliates of Toyota belong to the same manufacturing family and the same set of human resources practices are utilized” (Liker, 2004, p. 4.). Following Engström et al. (1996), the resolution of the aforementioned puzzle can be - 33 - found in taking an investigative approach and devote research scrutiny to socio-cultural factors of lean production. As a socio-technical system (Shah and Ward, 2003), lean production regards people as one of the system's core resources. Therefore, the central role of employees’ acceptance or rejection of the production model is given recognition (Spithoven, 2001). However, cultural differences play a role in this regard (Moreno, 1999). For instance in Japan, employees’ attitude related to quality of work life (QWL) differs from other parts of the world (Niepce and Molleman, 1996). Japanese workers' need for social relations is considerably more intense than the desire for personal achievement and independence. On the contrary, there is a clear preference in Western countries for personal growth needs which exceeds the need for social relationships. In these countries, the employees favor autonomy rather than the need to belong to a group (Niepce and Molleman, 1998). In this light, Oliver et al. (1994) analyzed 18 manufacturing firms in different socio-cultural settings. Nine of the plants investigated were located in Japan with the rest stemming from the United Kingdom. The investigation revealed that in terms of quality performance, all of the significantly higher achieving companies originated from the Japanese subset. Oliver et al. (1996) tested the same assumption on a bigger sample and with an expanded cultural context so that the subset comprised 71 manufacturing firms in eight countries. As a result of the analysis, the suppositions of the original research were further reinforced, lending support to the socio-cultural contingent nature of lean production. In relation with the socio-cultural context of lean production and human resources management, Lowe et al. (1997) managed to come to the same conclusion as afore articles by scrutinizing operational performance outcomes in companies with a Japanese cultural background and comparing the results with their European and North American counterparts. Their research also reveal an inconsistency, - 34 - as they highlight that human resources management practices do not seem to play a role in terms of performance outcomes in case of the different cultural backgrounds. In a similar setting, the introduction of lean production into Egyptian manufacturing firms was also observed to boost operational performance (Salaheldin, 2005). In a study about quality commitment of employees in a comparative study of Korean automobile companies, reward factors were disregarded as a motivator (Lee and Peccei, 2008). This is contradictory to well-established theories about reward systems (Lincoln and Kalleberg, 1990). However, this phenomenon can be attributed to cultural differences in lean production, since the Korean organizational culture is closer to the Japanese one (Lee and Peccei, 2008), where the need for personal achievement is less dominant (Niepce and Molleman, 1998). The implementation of lean production entails a fundamental change in the organizational structure of companies (Scherrer-Rathje et al., 2009). Employees’ ability to adapt to the freshly introduced circumstances is dependent on certain socio-cultural factors. In this process, the capacities of management to shift to new standards and workers’ ability to protect their interests have to be taken into account (Lewchuck et al., 2001). Therefore, the final outcome of the implementation of lean production has to be comprehended as a result of the contestation between management and labor (Shah and Ward, 2003). In connection with human resources management in lean production, the above described phenomenon is often referred to as democratic Taylorism (Adler, 1993). As a conclusion, the transference of the Japanese lean production practices depends to a great extent on socio-cultural aspects of the host nation. This includes historical and environmental context, such as long working hours, lifetime employment and seniority-based wage (James and Jones, 2014). - 35 - 1.3.2. The effect of work organization in the implementation and consolidation of lean production One aspect that has attracted an incremented amount of research scrutiny is the impact of work organization on the implementation of lean production. This section is devoted to the analysis of studies, which focus on this phenomenon. The implementation of lean production involves work standardization and routine tasks (Netland, 2013). As working conditions affect the whole spectrum of employees, it is therefore of interest to study these factors (Friedrich et al., 2016). Indeed, the involvement of certain practices related to work organization in the implementation of lean production is preferred due to its effects to strengthen operational performance (Rodríguez et al., 2016). The implementation process of the model od lean production is often facilitated by intensive training programs (Smith et al., 2003). In addition, the role of teams and team leaders (Marksberry, 2010) as well as team-based reward systems seem to have a positive impact on the overall performance of the company (Dubey and Singh, 2015). This is attributed to the nature of goal setting which contributes to employees’ attitude toward coming into possession of the necessary set of skills for their job (Wickramasinghe and Wickramasinghe, 2016). In addition, it is a feasible option to allocate employees into teams with their own responsibilities and giving them the freedom to allocate work among team members, rather than having everyone work as individuals (de Menezes et al., 2010). In this regard, Procter and Radnor (2014) present somehow controversial results about lean teams. They find that team performance is largely context contingent. In their study they argue that lean teams faced an overwhelming pressure and thus experienced difficulties in reaching their targets due to the imposition of meeting targets reduced the time available to take part in problem-solving improvement activities. Therefore, team targets - 36 - had to be adjusted and they called for a better comprehension of the role of teams in lean production. They argue that lean and how it interacts with the environment should be better understood. In the face of this, Delbridge et al. (2000) note that team work is an essential component of any lean work organization (Womack et al., 1990). Especially so, since, high-involvement work practices form a central part of lean production (MacDuffie, 1995). Team work is considered to be a productive element of lean production, especially if proper human resources management support is provided (Pil and MacDuffie, 1996). However, it is uncertain whether or not teams should be dealt with as a unitary concept (Shaiken et al., 1997). It seems that the role of the individual members of a team should be divided into at least two categories based on the responsibilities the members take: team leaders and team members (Delbridge et al., 2000). Similarly, a large degree of vertical and horizontal communication in terms of feedback (Dubey and Singh, 2015) can positively affect the results which a worker might attain (Moyano-Fuentes and Sacristán-Díaz, 2012). Effective feedback is an important part of establishing best-practices (Niepce and Molleman, 1998). In this light Brkic and Tomic (2016) highlighted the role of communication that could have an impact on the work force and make them more committed to the establishment of a lean environment. Communication, especially with the shop-floor seems to be a very important feature of the work organization in a lean environment, especially in the case of the senior and middle-management with the shop floor (Martínez-Jurado et al., 2014). Employee empowerment via the use of human resources management related tools plays an important role in this regard (Jones et al., 2013). The devolution of responsibilities to work teams (Khalaf et al., 2011) with team-based supervision (Barton and Delbridge, 2006) is required to ensure effective implementation and organizational - 37 - change (de Mendez et al., 2010). Birdi et al. (2008) reinforce the assumption that work organization practices, such as employee empowerment align well together with lean production practices. Nonetheless, a lack of significant results undermines these results, but there are a large number of positive connections between lean production and human resources and their management. In addition, the proposition that the effectiveness of lean production operational practices is work organization dependent is given evidence by Anand and Kodali (2010). In general, lean production brings about a change with respect to work organization that is subject to controversy (Moyano-Fuentes and Sacristán-Díaz, 2012). On the one hand, monotonous working conditions (Schouteten and Benders, 2004) can lead to increased employee dissatisfaction (Lindsay et al., 2014). Notwithstanding, Conti et al. (2006) claim that lean production is not inherently associated with an elevated level of stress but it is merely a consequence of management decisions. To sum up, traditional human resources management tools and practices should show a trend towards the adaption to lean production so that the beneficiary effects associated with it can be harnessed (Hiltrop, 1992). 1.3.3. The impact of trade unions in the implementation and consolidation of lean production The presence of trade unions is often regarded as a barrier to lean production implementation. Any progress towards lean production becomes substantially difficult in companies with unionized workforce. This is due to the fact that work organization related negotiation processes usually take time and unions are often - but not always - a source of resistance to change (Shah and Ward, 2003). In the face of this, Lewchuk et al. (2001) describes lean production as a result of the capacity of the management to shift to - 38 - new standards and unions ability to promote the interest of employees and resist change. The resistance may manifest in strikes. Therefore, the importance of labor-management negotiation in constraining and shaping corporate restructuring strategies is highlighted when implementing lean production. In this light, Lee (2004) found evidence for a competing trade-off between trade unions and company goals. In this case, the promotion of the trade union's interest was so effective that it negatively affected the achievement of company goals. Lee (2003) further reinforces the previous statement via an example from the Korean automotive industry. He demonstrates that trade unions possess the ability to cause a direct impact on lean production implementation. This is a result of the specification of relationship between the trade unions and management. More specifically, the power of the manifestation of workers' ability to promote their interest, i.e. strikes, can exert an opposite reaction with respect to the implementation of lean production. This occurs as a consequence of workers' dissatisfaction due to fatigue and monotonous work. In other cases, Kim and Bae (2005) analyzed two companies, one of them unionized (LG Electronics) and the other non-unionized (Samsung SDI). Both companies were highly sophisticated in their HRM practices. Samsung implemented lean principles, LG not. It was found that the adoption of high performance work organizations (HPWO) was highly dependent upon trade union representatives. Therefore, it is pivotal to know the state of unionization of a plant prior to making the decision about the implementation of lean production (Martínez-Jurado et al., 2014). Similarly, Delery (1999) accounts the slow progress of implementation of lean production in the US and European automobile industry for the presence of trade unions. It, however, is noted that trade unions cannot be fully made responsible for the slow- moving advance. Other factors, such as government barriers play a role as well. This - 39 - assumption is reinforced by Shah and Ward (2003) and Ahmed et al. (1991) who found no support for the supposition of the adverse effects of unionization. 1.3.4. The influence of knowledgeable workforce and participative management on lean production implementation and consolidation It is argued by Paez et al. (2004) that the implementation of lean production produces a fundamental alteration in the production system model. Thus, there is a need for a concurrent optimization of not just the technological systems but a considerable amount of attention must be paid to address people-related aspects as well (Bonavía and Marin- García, 2011). The success of the transformation process, however, does not equally favor all companies, due to the human element related complexities associated with the process of change (Scherrer-Rathje et al., 2009). Owning to the knowledge-intensive nature of lean production, workforce not only needs to possess a great variety of skills, but their responsiveness to change should also be taken into account (Drew et al., 2004). In addition, the commitment of top management is crucial during the whole process of the implementation process (Rafique et al., 2016), since the implementation of lean production also includes the flattening of the management structure due to the introduction of a TQM regime (Sohal and Egglestone, 1994; Nepal et al., 2011). Indeed, Shadur et al. (1995) added that prior to the implementation of lean production, there is a necessity to address people-related aspects. The acquisition of the proper skills has been highlighted by many researchers. For instance, Baril et al. (2016) and Meiling et al., (2012) argue that continuous improvement can be beneficial in terms of process performance and its effects start showing after a short period of time. Skilled workforce demonstrated that it could prove to be an asset to provoke a series of beneficial impact on the company. Morrison (2015) argues that knowledgeable workers may come up with in situ solutions for completing assignments even if the company is short of resources. - 40 - Line managers have a crucial role in the implementation process of lean production. Yet, this is often neglected and even researchers tend to focus on role of the management. However, a solution for certain barriers, such as employees' resistance to change could be lifted. This would be achieved by the devolution of responsibilities to line managers (Gollan et al., 2015). On this ground, Gupta et al. (2013) argue that the management of the company can formulate strategy to build favorable organizational culture and develop human resource to bring about required changes which are essential for the implementation of lean production. This means that human resource management and the aspects associated with it is a main driving factor in changing the mindset of the workers and forming them so that they become more receptive for complex changes. Indeed, attitude formation of the employees and the recruitment of the adequate, already receptive worker might be a key factor in the early phases of lean production implementation (Jabbour et al., 2013; Jürgens and Krzywdzinski, 2013). According to Yang and Yang (2013), a successful implementation depends on the company’s ability to integrate the “hard side” of lean production with its “soft side”. That is, the consideration of technical aspects only does not contribute to the achievement of results. In order to attain a successful lean production implementation one needs to address people-related phenomena in this regard as well, which have a remarkable significance during the transition process toward lean production (Sawhney and Chason 2005). Sometimes, however, the text book type lean production implementation can lead to employee dissatisfaction and can negatively impact the lean transformation as a whole (Lindsay et al., 2014). It is therefore important that managers opt for an enabling human resources management and foster employee satisfaction for improved performance outcomes (de Koeijer, 2014) and better well-being (Longoni et al., 2013). Similarly, Niepce and Molleman (1996) signal that Japanese employees’ - 41 - attitude related to quality of work life may be different. Under the new circumstances that the implementation of lean production brings about, workers are rather rewarded on the basis of the contribution they have made for the company (Wickramasinghe and Wickramasinghe, 2016). This variable pay program can be obstructive at first but then they tend to pay off and turn into a means of a facilitating factor (Karlsson and Ahlström, 1995). In general, the remuneration system seems to be an important aspect that managers should use carefully. 1.4. Conclusions Present paper provides a new classification of the literature concerning the role of human resources and their management in the implementation and consolidation process of lean production via a systematic literature review. The article builds on a sample of 74 articles, which handle the question of lean production and human resources in the same theoretical context. In this light, the evaluation of the available scientific literature has enabled the identification of four lines of research: 1) Socio-cultural factors, 2) Work organization, 3) Trade unions, and 4) Knowledgeable workforce and participative management. The proposed classification can be regarded a significant contribution towards the ability of academics and practitioners to comprehend the impact of human resources and their management in the implementation and consolidation process of lean production. The classification of the literature into lines of research also adds to the theoretical progress, which aims to enhance researchers’ comprehension concerning the role of human resources and their management in the implementation and consolidation process of lean production. In particular, the four proposed lines of research enables the deduction of progress by research, facilitate the work of new researchers who want to - 42 - delve into this area, reveal the contradictions and inconsistencies existent in the literature. This paper also permits researchers to find aspects, which have been scrutinized with respect to the human resources and their management in the context of lean production. That being said, aforementioned research area is divisible into four major lines of research. On the one hand, socio-cultural factors and trade unions pertain to the external environment of the company, that is, the firm has little control on these aspects. On the other hand, work organization as well as knowledgeable workforce and participative management are related to the internal environment of the company, where it has a higher degree of maneuvering ability. Therefore, depending on the profile, area of specialization and focus of interest of the researcher, it will be possible to identify new research questions that require empirical attention. So, the classification enables the detection of gaps, that is, areas that have yet to be subject to further research. One gap pertains to the relationship between lean production and human resources and their management in the implementation and consolidation phase of lean production. More specifically, a number of authors have signaled that the human element is an essential aspect of lean production (e.g. Emiliani, 2007a, b). Yet, there is no consensus for how work organization affects the outcome of lean transformation on the course of its implementation and consolidation. For this reason, it may be beneficial to adopt a multidimensional point of view and devise an empirical work for future analyses in this regard. The importance for an integrated perspective of human resources management and lean production has been recently discussed by Rodríguez et al. (2016). In order to be successful, lean production implementation requires organizations to apply lean principles in all organizational functions (Pakdil and Leonard, 2014). - 43 - Evidence was found that could lend support for the assumption that the implementation of lean production combined with human resource practices positively affected operational performance (Gollan et al., 2014). Since latter variable is regarded as a feasible indicator to measure the successfulness of the transformation process (Dora et al., 2013), the integration of human resources and their management into the bundle of lean production might be a desirable step towards a better understanding about lean production and human resources and how these two contribute to an incremented chance of a successful transformation. Yet, with the notable example of Marin–García et al. (2011), very few studies have endeavored to take such a holistic approach. With respect to the role of trade unions and their effect on the implementation and consolidation process of lean production, it is somewhat interesting that the empirical evidence pertaining to this field is subject to contradiction. Dong and Bae (2005) linked high performance work organizations to the presence of trade unions, while Shah and Ward (2003) could not corroborate the assumption that trade unions would negatively impact the performance of lean companies. For this reason, future studies should be carried out to put an end to this debate. Lean production is a management system that has spread from Japan, where it was first used, to various parts of the world. With the propagation of globalization, more and more countries are expected to embark upon the principles of lean production and opt for its implementation due to the benefits associated with it. It is therefore pivotal that managers are aware of the impact that socio-cultural factors have on lean production. With respect to the successfulness of the lean transformation, this particular attention can be crucial, since the Japanese working culture might be significantly different from the cultural context of the country in which lean production is about to be introduced (Engström et al., 1996). Therefore, thorough investigations should be - 44 - conducted to shed more light on the socio-cultural contingency of lean production. Especially so, since different management philosophies might have distinct implications depending on the national culture where the new system is put into place (Hofstede, 1983). Thus, lean production might be appropriate in one set of nations whereas its implementation can bear less suitability for the other. For this reason, more empirical evidence is necessary that provides a deeper understanding about the relationship between the socio-cultural context of lean production and the successful result of its implementation. Placing the focus on the scantiness of studies that analyze the causes of failures with respect to the implementation of lean production, Alagaraja (2014) suggests that factors leading to an abortive implementation of the management system should receive more scrutiny. Indeed, the literature has an almost exclusive focal point that is devoted to the investigation of factors that address the aspects that result in a favorable outcome. In the same time, the bibliography lacks the aforementioned investigative attention. Therefore, future lines of scholarly research should emphasize the causes that result in the lean transformation process to fail so that managers can attain the ability to study and learn from these failures and potentially gain the capability to prevent those circumstances from reoccurring. There are two main aspects on the subject of the fourth line of research, knowledgeable workforce and participative management that need more research scrutiny. Firstly, it should be made clear how the role of improvement groups influences employee participation and empowerment in the implementation and consolidation process of lean production. Then, evidence is required to acquire an insight into how afore process can be enhanced by the presence of more sophisticated incentive systems that take into account the positive contribution of the workers. Similarly, with respect to - 45 - the failed instances of lean production implementation, it could prove to be useful to prepare an investigative study concerning the role of human resources management in said process regarding the sectors of the industry where the it has had less success. More specifically, it could be investigated how the success ratio in aforementioned sectors react in the presence of an increased level of human resources management. Present paper has vital implications for managers who wish to study the impact of human resources and their management in their respective companies that have recently commenced or have already made the next step in the implementation of lean production. More specifically, it may provide practitioners with more extensive knowledge on the subject of the human element in the implementation and consolidation of lean production. This can facilitate their decision-making and count towards the factors that results in a successful outcome with respect to the implementation of lean production. These factors are divided into two categories based on the ability of the company to have an influence on them. Work organization as well as knowledgeable workforce and participative management pertain to the group where the firm is capable to manage, whereas trade unions and socio-cultural factors fall into the category of external factors where the company has only limited ability to maneuver. The limitations of this paper have to be recognized. One such limitation pertains to the methodological approach that was used in this paper. More specifically, while the methodology followed an inclusive conduct and the article sample is considered to be free of biases, it is impossible to completely rule out this sort of apprehension. Similarly, concerns may arise on the subject of the generalizability of the results, since the majority of the articles deal with the situation in the manufacturing industry where lean production is more prevalent, thus other sectors, such as health care and services are not sufficiently represented. - 46 - 1.5. References Adler, P. (1993): Time and motion regained. Harvard Business Review, pp. 97-108. Ahmed, N.U., Tunc, E.A. and Montagno, R.V. (1991): A comparative study of US manufacturing firms at various stages of just-intime implementation. International Journal of Production Research, 29 (4), pp. 787–802. Alagaraja, M. 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