A critical review of lean supply chain management frameworks: proposed framework

Lean supply chain management (LSCM) is one of the emergent fields of research. The present study objective is to perform review on existing LSCM frameworks and proposes a new LSCM framework. The study collected 30 LSCM frameworks with the help of extensive literature survey. The sample of LSCM frameworks have been classified based on novelty of the framework, contribution of various researchers to develop LSCM framework, verification status and modes of verification methodology used by the researchers, and also the degree of standardisation of LSCM elements. The study found that many researchers have proposed novel frameworks, lack of participation of practitioners and to some extent consultants in the field of LSCM framework development. It was also found that a huge number of incoherent elements were used to propose the LSCM frameworks. The study findings will give direction to the future researchers to propose a unified LSCM framework that will help to find out the coherent set of elements in the field of LSCM frameworks. Finally, the study proposes a comprehensive LSCM framework with the help of standard elements in the field of LSCM.


Introduction
In the present global scenario, physical distribution system plays a vital role in organisational productivity, quality and profits. The aforementioned factors helped the physical distribution system to develop into a broadened area and later it emerged as supply chain management (SCM). According to Williamson, Harrison, and Jordan (2004), SCM can be defined as 'the management of the interconnection of organisations which relate each other through upstream and downstream linkages between the different processes that produce value in the form of products and services to the ultimate consumer'. The SCM and manufacturing activities are closely related to each other in any organisation. The development of SCM also influences the performance of manufacturing activities. Manufacturing is continuously evolving since its development from the age of craft production to mass production and later on to lean production (LP) and agile manufacturing. These developments provoked to develop the field of SCM very rapidly. In the present scenario, the SCM is one of the key areas to determine the success and failure of the organisation with respect to customers (Christopher and Towill 2001). These thoughts led to survival of any organisation depending on 'getting right products, at the quality and quantity, at right price, at right time and to the right customer'. To achieve these objectives the organisations have started to use IT-based solutions, whereas, some other organisations have adopted and implemented advanced management concepts in addition to IT-based solutions. Finally, this idea formed two distinct paradigms, i.e. Lean supply chain management (LSCM) and agile supply chain.
In the present era, the manufacturing organisations are facing a huge number of problems with highly complex, complicated and prolonged supply chains due to globalisation (Chopra, Meindl, and Kalra 2007;Rudberg and Olhager 2002;Simchi-Levi, Kaminsky, and Simchi-Levi 2008). There onwards, few researchers (Oliver, Delbridge, and Lowe 1993;Ryan 2001) have participated in the research of LSC and have come out that lean principles can be used to improve SCM from manufacturing to the logistics operations by improved responsiveness to demand variations and reduced operating cost. The same study observed that many organisations have been benefited with LSCM through a closer relationship with key suppliers of the organisations. Subsequently, many researchers (Ariff and Ahmed 2005;Lewis 2006) have implemented lean principles in SCM activities and reported that the output of the organisations increased with a specific level of input. With that many researchers have started to come out with empirical and conceptual studies to build theory related LSC. Chen and Paulraj (2004) have reported that many research studies have proposed its own theories and frameworks to enhance SCM in the field of operations research. This kind of approach is resulted to develop directionless theories and frameworks. According to Soni and Kodali (2013), to develop unidirectional theories and frameworks in the field of SCM, the researchers should perform critical review of existing theories as well as frameworks and identify the gaps in the field of research then develop a new theory to fulfil the gap in the particular field based on existing theories. The study has observed that majority of the frameworks were developed without proper review of existing theories and frameworks in the field of LSC. Most of the LSC frameworks have been restricted to implement particular sector instead of generalisation of the frameworks ). However, Anand and Kodali (2008a) and Gomes and Mentzer (1988) have expressed that the stable and unidirectional theory and concepts of LSC are not yet fully developed. To overcome all these limitations, the present study has focused to give unidirectional, generalised and appropriate theory building with the help of existing literature in the field of LSCM.
The present study is organised as follows: Section 2 is devoted to literature review on LSCM and research question is raised to answer in the present research. Section 3 discusses guidelines to identify frameworks from LSC literature. Section 4 discusses the complete methodology and classification scheme used to classify existing LSC frameworks and gives a critical review of the existing LSC frameworks. Section 5 is used to propose a LSC conceptual framework and also illustrates its merits when compared with existing LSC framework. Section 6 describes the importance of each pillar in the LSC framework proposed in the present study. Section 7 is used to discuss the findings and implications of the present study. Finally, Section 8 is used to conclude the present study. Hines, Holweg, and Rich (2004) traced LP growth over the years from its inception and reported that LP has emerged as a manufacturing philosophy from just a production technique. The impact of LP resulted in organisations adopting the lean practices beyond boundaries of the organisations. As a result, the organisations have started to implement LP procedures, techniques, practices and tools (which will be referred to as 'elements' from now on) in SCM and product development activities. Of late, Womack and Jones (1994) have proposed the concept of Lean Enterprise (LE). Moreover, in the same research study, they have also proposed the concept of LSC and lean product development. The same study defined LE as a strategy, as the organisations have operationally synchronised although their functions are legally separated. According to Anand and Kodali (2008a), the adaptation of lean principles from manufacturing to the SCM activities is not a simple process. The reasons are: manufacturing processes focused on flow of material than information, manufacturing waste is possible to identify and quantify that is not possible in SCM activities to measure information flow waste, manufacturing processes can be controlled through top management and employees of the organisation, but SCM requires attention from entire supply chain from suppliers to customers. However, the main focus of lean principles is to identify waste in the process. Waste is an activity, which does not create any value to the customer or product. In SCM, wastes are created by improper information flow, material flow and funds in the system. According to Baum (2004), information and inventory have close relationship in the system and dependent on each other. One of the objectives of lean principles is to restrict inventory in the system. It is clearly reflected that the need of avoiding information waste in the SCM is to bring down inventory levels of the organisation. It is a well-known fact that the information is considered to a major cause of wastes in the SCM system. Hence, many researchers have started to implement lean principles in the field of SCM. Karlsson and Åhlström (1996) have proposed LE combination of lean product development, lean manufacturing, lean procurement and lean distribution. The study clearly identified the difference between LE proposed by Womack and Jones (1994) and LE proposed by Karlsson and Åhlström (1996). Womack and Jones (1994) have proposed the definition of LE, which goes beyond the boundaries of the organisation. On the other hand, Karlsson and Åhlström (1996) have proposed the concept of LE, which predominantly addressed the issues within the boundaries of the organisations. The present study has adopted ' Karlsson and Åhlström (1996) LE concept' to review the concept of LSC. Vitasek, Manrodt, and Abbott (2005) defined LSC as 'a set of organisations directly linked by upstream and downstream flows of products, services, information and funds that collaboratively work to reduce cost and waste by efficiently pulling what is needed to meet the needs of individual customers'.

Literature review
The concept of LSC strategy advises to make collaboration with the clients and work together to accomplish joint goals. Toyota also implemented a similar kind of strategy to attain LSC excellence. Toyota always communicates with their customers and suppliers as well as considers their opinions before implementing any changes in the SCM activities (Sezen and Erdogan 2009). However, many organisations have struggled to implement LSC principles due to the lack of awareness and improper implementation procedures. Many studies have discussed the LSCM as a cost reduction and waste removal strategy.  have presented a framework of LSCM with seven dimensions. All dimensions are derived from the literature, but the study has performed very limited number of literature review. However, the same study has proposed a framework to implement in pork industry, which leads the generalisibility of the framework is lacking. Lamming (1996) have performed an initial work on lean supply chain and focused on lean supply, exclusive of other aspects of SCM. Francis (1998) has worked on LSCM with limited focus on lean information systems only. However, the same study lacks in the overall approach towards the set of procedures constituting LSCM. Nabhani and Shokri (2009) proposed a model with a combination of six sigma methodologies and lean principles can be implementable in SCM activities in a food distribution organisation. However, the lean principles proposed in that research are mostly concentrated on plant-based activities and did not focus much on complete SCM as a whole. Taylor (1999) has investigated on lean relationships with supply chain and did not reveal any kind of elements to achieve excellence in the field of LSCM. Cox, Chicksand, and Palmer (2007) have implemented lean strategies in beef, lamb and pig supply chains and revealed there was a positive impact on SCM. But, the study did not reveal the constructs of lean supply chain. Anand and Kodali (2008a) have reviewed LSC literature and identified gaps existing in the present literature. The same study has reported that many research studies focused only on individual aspects of LSC and very few research studies focused on both upstream and downstream activities of the organisation. Secondly, most of the studies focused only on upstream activities of LSCM. The same study has proposed a framework based on researcher's experience in the field of LSCM. Reichhart and Holweg (2007) also reported similar kind of observation from LSC literature. Soni and Kodali (2012) have investigated leagile SCM elements and performed empirical analysis to identify leagile elements suitable for Indian manufacturing industry. The same study restricted to identify lean, agile and leagile elements from the existing frameworks in lean, agile and leagile, respectively.  and Adamides et al. (2008) have implemented value chain analysis techniques and revealed opportunities for strategic change in a UK agrifood supply chain. The same study also discussed a primary framework of an integrated SCM actions based on the application of lean principles. The same study has clearly elaborated how to implement lean practices in agri-supply chain. The complete review of literature clearly revealed that the framework proposed in the field of LSCM was mostly based on a case study approach methodology. Henceforth, generalisation of these frameworks is very difficult due to its limited focus in the particular sector. Hence, the present study has reviewed the frameworks of LSCM to identify its limitations and proposed a comprehensive conceptual LSCM framework to fulfil the gaps in the field of LSCM frameworks in terms of generalisation of the frameworks. To fulfil the required task, the present study has raised six research questions and tries to trace the gaps based on these six questions raised in the present research in subsequent sub-section.

Research questions
The present study investigates the rate of novel frameworks proposed when compared with the adoption of existing frameworks. Generally, any new field of research encourages greater number of novel frameworks than adaption of existing frameworks (Soni and Kodali 2013). In order to verify the aforementioned statement, the present study tries to answer the following research question 1(RQ1).

RQ1
: What is the present status of framework development in the field of LSCM?
The study further finds out the contribution of academicians, practitioners and consultants in the development of LSCM frameworks. According to Soni and Kodali (2013), academicians contributed more towards theory building, while practitioners and consultants contributed to verify or practice the theories. To verify the aforementioned statement, the study raises another basic research question 2 (RQ2).
RQ2: What is the contribution of academicians/ practitioners/consultants in the development of LSCM frameworks?
For any field of research to reach maturity stage as a discipline, the proposed theory should be supported by working on the study practice (Croom, Romano, and Giannakis 2000;Storey et al. 2006;Tranfield and Starkey 1998). Hence, the study tries to answer the research questions 3 and 4 (RQ3 and RQ4).
RQ3: How frequently are these proposed LSCM frameworks validated? RQ4: What kinds of modes are used to verify the LSCM frameworks?
The success rate of any manufacturing philosophy or strategy depends on what type of elements proposed in a particular framework. The present study tries to find out the elements used to develop LSCM framework and also standardisation of elements in the field of LSCM. Hence, the study raised two research questions i.e. research questions 5 and 6 (RQ5 and RQ6).
RQ5: what are the elements used to develop a proposed framework?
RQ6: What is the degree of standardisation of the elements in the field of LSCM?
In order to find out the answers to aforementioned six research questions and also to critically analyse the inconsistencies presented in the existing LSCM frameworks, the study has identified the frameworks and analysed on various aspects. The subsequent section tries to find out what is a framework.

Identification of existing LSCM frameworks
The term framework is one of the popular phrases in the field of operations research. However, many researchers have confused in defining what a framework is. Few researchers discussed the framework as a group of elements to implement in an organisation. On the other hand, some other researchers discussed that the framework is represented with the help of diagrams or graphical representation. Many researchers have used the term framework and model interchangeably. It clearly indicates that there is a lot of confusion to define the framework and to differentiate with the model. Hence, the present study conducted a literature review to find out an appropriate definition of the framework. Aalbregtse, Hejka, and McNeley (1991) reported that a framework consists of the complete picture of the business goals and also presents a systematic implementation methodology to accomplish the organisation business goals. Hakes (1991) reported that a sound framework should answer the connection between the concepts and the practical application. A framework consists of a set of fundamental assumptions and principles that discuss the actions to be performed (Popper 1994). Struebing and Klaus (1997) reported that a framework consists of the complete plan of implementation and ensure each step of build-up procedures also. According to Yusof and Aspinwall (2000), a model answers the question 'what is', whereas, a framework answers the question 'how to'. Anand andKodali (2010, 2008b) concluded that the framework is a guiding torch to the organisation employees to implement any philosophy in the organisation. In order to identify LSCM frameworks, Soni and Kodali (2013) raised the following three questions: Q1: Does the LSCM framework describe all elements presented in the system? Q2: Does the LSCM framework illustrate the complete association among the elements presented in the system? Q3: Does the LSCM framework describe the methodology of implementation in practical sense?
If the proposed LSCM framework answers all three questions affirmatively, then the study is considered as a framework in the present research. Subsequently Section 4 provides the five steps of methodology to review and identify inconsistencies presented in the LSCM frameworks.

Research methodology
The complete methodology consists of five steps, which are given as follows: STEP 1: The present study considered the year 1988 as the starting point to collect literature from four online data portals and Google online search also. The reason to select the year 1988 as the starting point is because in that year the term LP was introduced. The end point of articles collection is the year 2013. Hence, the present study considered 26 years' of period to review literature in the field of LSCM. STEP 2: The study collected 748 articles from the total online data portals. The study filtered all articles based on focus of journal and finally the study found 546 lean related articles in 24 operations research journals in four online data portals i.e., Emerald, Science Direct, Taylor and Francis, and Springer Link. Table 1 shows the list of selected journals that are considered in the current study. The study found that out of 546 lean related articles, only 118 articles are addressing the issues of LSCM. Other than these articles, the study also included Google search and textbooks materials to find out existing LSCM frameworks in the literature. STEP 3: In order to find out the LSCM frameworks from the collected literature, the study used the aforementioned guidelines to find out the total LSCM frameworks existing in a sample of the literature. The study found 30 LSCM frameworks (given in Appendix 1) from the LSCM literature. However, the present study is projecting all these LSCM frameworks only as a sample of the existing frameworks in the literature. It is an impossible task to collect the complete set of LSCM framework proposed in the literature. STEP 4: The research question raised in Section 2 will be answered in the present step through the classification of the sample of LSCM frameworks with focus on various aspects. The present study has divided the classification scheme into two broad categories i.e. generic criteria and LSCM specific criteria.

Generic criteria 4.1.1. Novelty of framework
The study focuses to find out whether the framework is built on existing LSCM framework or not. If the framework is not based on existing LSCM framework, then the study considered it as a novel framework. Otherwise, the proposed framework is considered as an adapted framework. This kind of classification scheme will help to find out the present trend of theory building in LSCM frameworks. If the study finds higher number of novel framework in the literature, it is a clear indication of lack of research efforts to generalise the existing LSCM frameworks. If the results are altered, then it indicates that the research is developed within the restricted boundary. The present classification scheme helps to answer research question 1 (RQ1).

Source of the framework
According to Yusof and Aspinwall (2000), the frameworks can be classified into three categories based on researcher's background i.e. academic-based, practitioners-based and consultants-based framework. Academic-based framework represents the framework developed based on academic research in academic institutions. The framework, which is developed from the industry implementation procedures or a case study, it can be categorised as a practitioners-based framework. If the framework is proposed based on experience of experts, then it is called consultants-based framework. This kind of analysis will help to find out the gap between theory building and practice in the field of LSCM. The present section of classification is helping to answer the research question 2 (RQ2).

Framework verification
The present classification will help to find out an answer to research question 3(RQ3). The study tries to find out whether the proposed framework was verified by the researcher. The framework consists of a set of elements and presents the path to implement these elements in the real practice environment. If the framework was implemented in practice, then the framework is considered as verified. The framework verification can be useful to find out the drawbacks of the framework. Based on identified drawbacks, the framework is modified and rebuilt to suitable real-time environment or experience or feedback. This kind of theory building is good to any field of research (Anand 2009). The verified frameworks always encourage practitioners to implement in the organisation.

Mode of verification
The proposed framework can be verified by applying various methods, i.e. case study, survey, focus study, Delphi, and combination of these methodologies. Case study approach uses qualitative data collected from interviews or secondary data. Survey approach generally uses quantitative data collected from various people. Delphi and focus study get the opinion of various experts to verify the proposed framework. The mode of verification study will help future researchers to find out what are possible modes of verification methods available and are also useful to answer the research question 4 (RQ4) raised in Section 2.

Framework elements
In general, each framework proposed has some common or essential practices and tries to develop the complete framework through building-up the relationship between those elements. The present step is useful to find out what are the elements used to develop a framework and also useful to find out the standard elements used in the field of LSCM. Hence, the present classification scheme is useful to answer the research questions 5 and 6 (RQ5 and RQ6) raised in Section 2. STEP 5: After completion of classification of the frameworks, the study analyses the classification data to find out an answer to the research question posed in Section 2 and also finds out the inconsistencies presented in the sample of the LSCM framework considered in the present study.

Classification and analysis of LSCM frameworks
The present study collected 30 LSCM frameworks with the help of extensive literature survey to perform classification and analysis as per generic criteria and LSCM specific criteria explained in earlier sub-section. The complete details of the classification and analysis of the existing frameworks is given subsequently as a part of the present sub-section.

Novelty of framework
Generally any operations management research field should require novelty or originality of theory building to establish it as one of the promising research field. At the same time modifying existing theories as per present day requirements also plays a vital role in developing a coherent theory building in the field of any research. Hence, the study tries to analyse the same issue in the present sub-section. Table 2 shows the frequency distribution of a number of frameworks that are novel or adapted. Table 2 clearly indicates that 93.33% of the frameworks fall in the category of novel frameworks. This kind of trend is good for growth of LSCM but at the same time too much of novelty theory building leads to incoherent focus of research in the field of LSCM. Only 6.67% of the frameworks were belonging to the category of adapted frameworks. Hence, the researchers should give equal importance to build theory based on the existing theories, i.e. adapted framework.

Source of framework
The frequency of frameworks published as academic-, practitioners-and consultants-based frameworks is given in Table 3. Table 3 reveals that 66.67% of the existing LSCM frameworks are proposed by academic researchers. The study also reveals that only 30% of the frameworks are proposed by consultants. One of the important observations is that contribution of practitioners to develop frameworks did not exist. The study also identified that only one framework proposed a combination of consultants and academicians. Hence, the present study suggests that there is an urgent requirement to bring all three fields of researchers under one umbrella to develop a more practical oriented framework with a strong theoretical background in the field of LSCM.

Framework verification
The main objective of the framework is to help to the industry managers to implement research practices in the specific area of the organisation. Hence, the researchers should verify the proposed framework that encourages industry managers to implement already verified framework in their organisation. The verification of proposed theory plays a vital role to develop useful and appropriate theory in any research field (Flynn et al. 1990). Table 4 gives the frequency of frameworks that are verified in the selected sample of LSCM framework. The study observes from Table 4 that only 36.67% of the frameworks were verified by applying various research methodologies. A few frameworks were only generally proposed by the researchers to bring out some novelty thought in the field of research (Soni and Kodali 2013). These kinds of research framework are only useful to Table 2. Frequency distribution of number of frameworks those are novel or adapted.

Mode of verification
It is important to find out the verification methodology used by various researchers to verify the proposed LSCM framework. Table 5 gives the frequency of modes of verification for applicability of frameworks. Table 5 clearly reveals that most of the frameworks were verified by applying case study verification research methodology. Only few researchers have used survey research methodology to verify the proposed framework. The remaining research methodologies were not used by any of the researchers to verify the proposed framework.

Elements of frameworks
The study found that the proposed frameworks addressed a wide range of concerns in the field of LSCM. So the comparison of these frameworks on same scale is more difficult as well as in some cases it is an impossible task. However, it is important to find out the most popular elements as well as standard elements in the field of LSCM. To do this, the study dealt with • What are the lean elements used to develop LSCM framework by various researchers? • Did the researchers have considered any standard lean elements to build selected LSCM framework?
The same kind of approach was followed by Soni and Kodali (2013), Mishra, Anand, and Kodali (2006), Kodali (2008a, 2008b) to develop a conceptual framework in the field of SCM, world class maintenance, total quality management and manufacturing excellence frameworks, respectively. The frequency of occurrence of lean supply chain elements in various LSCM frameworks is given in Table S1.
From Table S1, the study found 129 unique lean supply chain elements. The phrase or words of the elements have been considered to find the meaning of the element. The same-meaning elements are clubbed and considered that element as a single element. For example, supplier relationship/building and maintaining long-term relation with customers and suppliers/strategic alliances and long-term partnerships between customers and suppliers/ the development of supplier associations/supplier alliances/build trust based alliances with ethical supply Table 3. The frequency of frameworks published as academic-, practitioners-and consultants-based frameworks.

Mode of verification Frequency Framework articles
Case study 9 1, 2, 4, 15, 18, 20, 21, 27 19 3, 5, 6, 7, 8, 9, 11, 12, 13, 14, 17, 19, 22, 23, 24, 25, 26, 28, 29 Total 30 chain partners/develop strategic long-term partners/longterm partnerships/long-term agreements/establishing long-term purchasing and supply commitments/close relationships with suppliers and customers/supplier collaboration. It is observed that the objective of the aforementioned entire set of elements is to maintain the long-term relationship with suppliers. The study does not believe that all these 129 elements are independent of each other. The study believes that if the researchers have performed principal component analysis on these elements, all these elements will fall under suitable independent elements.
All these elements are two categories: broader in nature and issue specific that means the framework addresses the specific issue. For instance, the elements like 'Just-in-time (JIT) production', 'continuous improvement (CI)', 'elimination of waste', 'customer focus' and 'supplier management' are in broader sense as proposed by the researchers. Other elements like 'supplier location', 'kanban', 'small lot size', ' single piece flow' and 'milk run' are issue specific or subset of broader domain elements. General observation of the present study is that the generic frameworks have broader elements when compared with the issue specific frameworks. However, the main purpose of the present study is to identify the standard LSCM elements instead of comparing the LSCM frameworks just based on strengths and weakness of the frameworks. Majority of the researchers like  have discussed LSCM with respect to supplier relationships and related issues only. Other group of researchers have proposed frameworks including manufacturing as well as supply chain activities, which are playing a vital role to implement LSCM in the organisation (Anand and Kodali 2008a;. Few researchers have reported that in order to attain excellence in LSCM, the organisations should implement lean principles in the manufacturing, supply chain as well as in product development procedures . The different views of researchers on LSCM resulted in accumulation of a lot of incoherent elements, which is seen in frequency analysis of LSCM frameworks. The frequency analysis of the elements clearly revealed a deficiency in standardisation of elements used to develop LSCM frameworks. Only 6.97% of the elements repeated more than five times in the sample of LSCM frameworks considered in the present study. The study also revealed that only 27.13% of the elements are repeated more than two times. It clearly reveals that the different perspectives of the researchers in the field of LSCM have resulted in the development of incoherent and large number of elements. In order to find out the standard elements in the field of LSCM, the study considered the elements that repeated more than once in the sample of frameworks considered as a standard element. In the process, the study identified only 35 elements from the literature. The study formed a team of 12 members with 6 academicians, 3 practitioners and 3 consultants to standardise these 35 elements. The team also helped to find out the various standard elements from these 129 elements, which was also backed up by literature survey to identify the standard elements. Adamides et al. (2008) have revealed importance of supporting collaboration in the development and management of lean supply networks. Narasimhan and Das (2001) also discussed that the higher the strategic alignment of purchasing strategy with manufacturing strategy which impacts positively on both SCM and manufacturing performance. The performance of SCM is also linked to the processes and enhancement programmes carried out at the production level (Voss 1995). Many researchers such as Blackhurst, Wu, and O'Grady (2005), Childerhouse, Aitken, and Towill (2002), the magnitude of the effects of product development features on SCM performance and importance of maintaining strong product development teams to implement effective SCM strategies. The degree of collaboration among SCM strategy and product development strategy resulted in positive impact on the SCM performance and product development performance, which is proved in a case study approach (Doran et al. 2007). The variety of the product is effecting on SCM performance of the organisation. The differences among created variety, produced variety, transported variety and customer requirements resulted in lower SCM performances. Hence, the present study has performed similar kind of analysis on LE, LM, LPD frameworks in order to identify standard lean elements, which helped to improve the performance of SCM activities and overall organisational performance also. In the process, the study found 82 LSCM related standard elements to propose a comprehensive LSCM framework.
The research team also tried to find out the broader areas of the LSCM elements to propose the pillars of the framework. The team suggested that if the number of elements repeated is more than 20% of the framework, then those elements have been considered as pillars of the framework. Accordingly, the study has identified seven elements as pillars. These seven elements are further filtered out to four pillars of the framework after removing overlapping of the domain. The team suggested additional four pillars with the experience of team members as well as based on analysis performed on lean manufacturing, LE and lean product development. In total, the study identified eight pillars and 82 subelements from the extensive literature survey, frequency analysis and inputs from the experts. The research team have distributed all 82 elements among eight pillars with the help of thorough discussion among the team members. The pillars of LSCM framework and respective elements are given in Table 6. Finally, the study proposes a comprehensive LSCM framework with the help of extensive literature survey as well as inputs from expert team members that includes academicians, practitioners and consultants. The conceptual LSCM framework is given in Figure 1.

A conceptual framework of LSCM excellence
In the previous section, the study has proposed a comprehensive LSCM framework to achieve excellence in supply chain activities. Generally, the frequently used elements cannot be separated from the field of any research. The proposed LSCM framework elements have been frequently used in the field of LSCM framework. Hence, the proposed LSCM framework is being treated as an excellence framework. However, the importance of checking the reliability and validity of these proposed pillars cannot be ruled out. Hence, it is proposed for future research work in the field. If the reliability and validity on the pillars of the proposed framework are carried out, then the important elements can be identified and these elements may be used as an integral part of LSCM in a particular organisation. The proposed LSCM framework contains the following features as compared with the existing sample of LSCM framework in the literature: (1) The proposed framework includes 9 pillars and 87 elements identified from the literature in the field of LSCM. (2) The framework proposed is based on the opinion of consultants, practitioners and academicians. It overcomes the general inadequacy presented in the sample of existing LSCM framework. (3) One of the main limitations of the existing LSCM frameworks is the abstractness of the framework. To overcome this limitation, the present study made an attempt to propose comprehensive LSCM framework. The number of pillars and elements used in the proposed framework are much higher than the sample of existing LSCM frameworks. It clearly indicates a comprehensive nature of the framework. However, it may be possible to miss out some of the elements. According to Weick (1979), it is impossible to build a framework with all the characteristics together such as general, accuracy and simple. (4) The sample of reviewed LSCM frameworks contains a majority of the elements recognised in the proposed LSCM framework.

Pillars of comprehensive framework of LSCM
The proposed comprehensive LSCM framework in the present study has 9 pillars and 87 elements proposed under these 9 pillars. The present section tries to bring out the importance of each pillar and how these pillars are integral part of the comprehensive LSCM framework proposed in the present research work.

Top management commitment
Betchel and Jayaram (1997) have reported that the SCM activities' plan require some strategy formulation to implement in the organisation. The action of top-level management is compulsory to implement any kind of operational strategy in the organisation. The top manage-ment should provide necessary infrastructure and training to the organisation employees (Kouzes and Posner 1995). According to Roth, Giffi, and Seal (1992), one of the objectives of top management commitment is to create the enthusiasm and inspiration in the organisation employees to accomplish the organisation's goals. However, around 7% of the existing LSCM frameworks were proposed as one of the elements to achieve excellence in the field of LSCM frameworks. All aforementioned factors influenced to include top management commitment as one of the important pillars in the proposed LSCM framework.

Supplier relationship management
In contemporary scenario, the manufacturing of products to high quality standards is not the only criteria, but also delivering the products to the customer at right time, at right quantity, at right place, at right cost also plays an important role in the success of the organisation. All these activities are always integrated with the suppliers. The suppliers play a vital role in the success of any organisation (Chin et al. 2004). Hence, many organisations have focused on maintaining long-term relationships with the suppliers (Park et al. 2010). Around 70% of the frameworks have proposed suppliers' relationship related elements in the existing LSCM framework. Hence, the present study also proposed supplier relationship management as one of the important pillars to implement the proposed LSCM framework in the organisation.

Lean Supply Chain Management
Top management commitment and leadership Figure 1. The conceptual LSCM framework.

Customer relationship management
In the present global scenario, the success of the organisations is based on how well the organisation delivered the products and services to the customer (Boydell, Burgoyne, and Pedler 1991). The organisations should give equal importance to both internal and external customers to provide better services to the final customer (Robson 1986). Many organisations have started to maintain long-term relationship with the customers and performed analysis on various needs of these customers to provide better service in terms of cost and warranties with the help of flexible manufacturing system (Grant and Schlesinger 1995).
Moreover, the frequency analysis shows that around 26.67% of the frameworks have proposed customer relationship related elements to achieve better results in LSCM activities. Hence, the present study also proposed customer relationship management as one of the important pillars in the proposed framework.

Information technology
The success of present complex supply chain depends on how well the information flows across the supply chain activities. The use of information technology is prerequisite to control information flow across the supply chain activities (Tan, Lyman, and Wisner 2002). In the present scenario, the organisations are not considered as independent entities, but the organisations should work as a part of multi-organisations, multi-echelon networks, delivered products and services to the end user (Christopher 1992;Lambert and Cooper 2000). The supply chain literature clearly revealed that integration of multi-company networks is very much significant (Burgess 1998;Cooper, Lambert, and Pagh 1997;de Leeuw, van Goor, and van Amstel 1999;Mason-Jones and Towill 1999;Norek and Pohlen 2001). Moreover, the information technology utilisation is a necessary requirement to maintain and control these multi-networks as well as to improve supply chain effectiveness (Lee and Billington 1992;White and Pearson 2001). Around 57% of the frameworks have proposed Information Technology related elements to achieve excellence in the field of LSCM. Hence, the present study also included Information Technology as a pillar in the proposed LSCM framework.

JIT manufacturing
The concept of SCM is initiated and developed in the manufacturing organisations (Vrijhoef and Koskela 2000). According to Huang, Uppal, and Shi (2002), various new methodologies and tools were developed by manufacturing organisations to improve productivity, customer satisfaction, lead time reduction and quality. The SCM concepts were used initially in the Toyota production system as a part of the JIT delivery system (Krafcik 1988). It clearly indicates that JIT operations and SCM operations are mutually integrated with each other. Around 36.66% of the frameworks have proposed JIT as an element of LSCM framework. Hence, the present study also considered it as one of the pillars to achieve excellence in the field of LSCM.
6.1.6. Elimination of waste Initially Toyota organisation engineers have applied commonsense and practical knowledge to reduce setup time and defects in the manufacturing operations. They have identified waste activities in the manufacturing operations. According to them, waste is an activity that is not required to the customer for their needs. According to Ohno's, the waste can be classified into seven wastes: over production, inventory, motion, over-processing, defects, transportation and waiting (Imai 1997;Liker 2004;Monden 1993;Taylor and Brunt 2001;Womack, Jones, and Roos 1990). According to Anand and Kodali (2008a), all seven wastes are applicable and also identified in LSCM activities also. Around 60% of the frameworks have proposed it as one of the elements to implement in LSCM frameworks. Hence, the present study also recommends it as one of the pillars to achieve excellence in the field of LSCM.

Continuous improvement
CI is one of the important alternatives to improve organisational output performance (Corbett and Rastrick 2000;Milakovich 1991). The main objective of CI is to implement initiatives that are improving the success rate and reducing the failure rate of activities in the organisations (Juergensen 2000). It is achieved by incremental improvement of products, processes and services with the help of teamwork over a period of time. All these factors influenced the researchers (16.66% of the frameworks) to propose CI as one of the elements in the LSCM frameworks. It indicates that a significant importance was not given by various researchers for CI. However, the literature clearly indicates that CI is a very important element to achieve excellence in LSCM activities. Hence, the present study has given importance to CI as one of the pillars to achieve excellence in LSCM.

Logistics management
One of the roots of SCM exists in the field of logistics management. The focus of SCM is to develop coordination, collaboration as well as long-term relationship building throughout the channel members, which are not a part of logistics management (Ballou 2007). It clearly indicates that SCM activities have much broader focus than logistics management. The frequency analysis indicates that few researchers have used logistics management as a part of LSCM framework. However, logistics management cannot be separated from SCM activities. Hence, the present study recommends logistics management as one of the pillars to implement in the comprehensive LSCM framework for any organisation.

Discussion
The present study tries to find out the inconsistencies presented in the sample of the frameworks studied. The study raised certain issues in the form of research questions to address inconsistencies in the sample of the existing frameworks as well as to propose future actions required to develop an innovative LSCM framework. One of the important observations from the study is that most of the frameworks fall in the category of novel framework. It clearly indicates that theory building is incoherent in the field of LSCM frameworks, but it also indicates that appropriate amount of theory building has already taken place in the field of LSCM framework. Hence, the study reveals its opinion that the future frameworks could be developed based on the existing framework. This kind of methodology will help to develop coherent theory building in the field of LSCM frameworks. The present study also reveals a lack of participation from the practitioners-based frameworks when compared with academic-based and consultants-based frameworks. The practitioners are generally practice in real industrial environment. According to Soni and Kodali (2013), the practitioners plays vital role to develop more practicable and realistic frameworks in any field of research. However, the practitioners can be helpful to identify limitation of implementation of various elements, which is useful to propose realistic and implementable of framework in the field of research. The study suggests that the contribution of practitioners and to some extent consultants in the field of LSCM frameworks, if increases, that may result in developing a widely acceptable framework. The study also suggests that if the academicians collaborate with practitioners and consultants to develop the framework, such efforts will result in building sound theory grounding and practice sense of the frameworks. This kind of frameworks is very less in number in the field of LSCM framework. The present study also reveals that the number of LSCM frameworks, which have undergone verification process is significantly less. This kind of trend definitely will increase the gap between the theory and practice. Hence, the study suggests that the researchers should take responsibility to test or verify the proposed frameworks by applying various verification methodologies. It will help to develop innovative LSCM frameworks that encourage the practitioners and organisation managements to implement these frameworks to achieve excellence in the field of LSCM frameworks. Malhotra and Grover (1998) reported that the case study and qualitative approaches are generally used to verify emergent field theories in the initial stage of research before it reaches to the maturity stage. The study also observed that the case study verification approach was used by many researchers to verify the proposed LSCM frameworks. Hence, the study supports the fact that the LSCM is in initial stage of development. Another observation from the present study is the incoherence of elements used to develop LSCM frameworks. This kind of results will occur only when the scope and focus of the frameworks are different from each other and also the problems addressed by these frameworks are very different. However, for any field to reach maturity stage it requires a set of coherent elements. Generally, principle component analysis will help to find out descriptive set of main elements of the frameworks and subsequently the remaining sub-elements can be identified through various processes. Such kind of practices definitely will help to find out the coherent set of elements and pillars to develop the frameworks in the field of LSCM. One of the important features of the proposed framework in the present study has been developed with consultation of academicians, practitioners and consultants.

Implications
The study contributes in the field of theory building as well as practical domain of LSCM frameworks. The study has given clear guidelines to identify LSCM frameworks from the literature. The study is also useful to the researchers to distinguish the framework from the model. The study identified the possible research methodologies to verify the proposed LSCM frameworks and also frequently used research methodology to verify the existing LSCM frameworks. The present study suggests to perform reliability and validity analysis to find out suitable and coherent set of elements as well as pillars from the proposed conceptual LSCM framework.
The proposed LSCM framework pillars are derived based on frequently used elements in the existing framework. Hence, the proposed LSCM framework can be useful as a ready reference to the consultants and practitioners to identify pillars of LSCM field. The practitioners and managers can use these pillars to identify the weak areas in their organisation to implement the LSCM principles. The managers generally struggle to benchmark operations in the organisation. In this kind of situations, the proposed framework can be taken as a reference to benchmark all activities across the organisation. The present study suggests performing an appropriate statistical analysis to find out a feasible set of elements to formulate the LSCM strategy to implement in the organisation.

Conclusion
The field of LSCM is one of the emergent areas in the field of operations management, which resulted in many researchers contributing to develop the frameworks. The present study observed that no research review articles were available to find out inconsistencies and inadequacies in the existing framework of LSCM. This kind of analysis is useful to develop a coherent set of elements in the field of LSCM frameworks. Hence, the present study conducted literature survey and identified 30 LSCM frameworks based on guidelines given earlier in Section 3. These 30 frameworks are focused as a sample set of LSCM frameworks instead of a complete set of LSCM frameworks. One of the main focuses of the present study is to find out the inconsistencies presented in the LSCM framework with the help of research questions posted earlier in Section 2. The study found that the participation of practitioners in the field of LSCM frameworks were very low as compared with academicians and consultants. The present study also revealed that many proposed frameworks are novel frameworks and not verified by using any kind of research methodology. The study found that case study research methodology is the most popular one to verify the proposed frameworks. The study also investigated to find out the elements that have been used by various researchers to propose LSCM frameworks and to know the degree of standardisation of the elements in the field of LSCM. The study identified that a huge number of dissimilar elements were used by researchers to propose the LSCM frameworks. All these elements fall in the various functional areas of the organisation such as inventory management, operations management, supplier and customer relationship management, top management commitment, etc. Hence, the identification of standard elements from the literature is a difficult task due to a huge number of elements used by the researchers to propose LSCM frameworks.
The limitations of present study are not performed to any kind of verification on proposed frameworks, it will consider as a future part of the research due to scope research work. The study suggests that the future researchers need to dedicate their efforts to find out the suitable coherent elements by using exploratory techniques such as principle component analysis based on respective sector. The study also suggests verifying reliability and validity of proposed conceptual framework of LSCM to implement in the organisations.

Supplemental data
Supplemental data for this article can be accessed here http:// dx.doi.org/10.1080/09537287.2015.1004563.

Notes on contributors
Naga Vamshi Krishna Jasti did his BTech (Mechanical Engineering) from Jawaharlal Nehru Technological University, Hyderabad and ME (Mechanical Engineering) from BITS Pilani, Rajasthan. He completed his PhD from BITS Pilani. He is presently assistant professor with Department of Mechanical Engineering, BITS Pilani, Pilani Campus, Pilani, India. He is also incharge for Bharat Forge and SKF India Ltd, Pune collaboration programmes for the past eight years. He has over eight years of teaching experience at under graduate and graduate levels. His areas of research interest are lean manufacturing and green manufacturing.
Rambabu Kodali is presently a director, National Institute of Technology, Jamshedpur, India. Prior to appointment, Rambabu Kodali was a professor in the Department of Mechanical Engineering of BITS Pilani, Pilani Campus, India and also 'Shri S.K. Birla Chair Professor' from 2 April 2012 to 2 August 2012. He was a group leader (HOD) of Mechanical Engineering Group and Engineering Technology Group from 1994 to 2004, respectively, to 2010. He has 27 years of teaching/research experience and 16 years of administrative experience as a group leader (HOD). He has published around 200 papers in various national and international journals. His research areas are: Toyota production system, lean manufacturing, manufacturing excellence, FMS, innovative product design and development, supply chain management and manufacturing management. He has supervised nine PhDs and currently supervising three more. He has completed 11 research projects in FMS, Computer Integrated Manufacturing Systems, World-class manufacturing and manufacturing excellence. He has developed 4 on-campus degree programmes and 14 offcampus degree programmes at BITS Pilani. He has developed and established the state-of-theart FMS laboratory apart from modernising various Mechanical Engineering laboratories at BITS Pilani, Pilani campus, Pilani, India.