مفهوم سازی مجدد اثرات ناب بر هزینه های تولید با شواهدی از برنامه F-22

A central tenet in the theory of lean production is that the implementation of lean practices will reduce waste and thereby decrease costs. However, not all lean implementations have produced such results. Apparently, this effect is moderated by several factors, potentially even to the point of reversal. It is important to increase our understanding of how this might occur. In this paper, we explore how novelty, complexity, instability, and buffering affect the relationship between lean implementation and production costs. An interest in these factors drew us to study the case of Lockheed Martin's production system for the F-22, an extremely complex and innovative product. To build theory, we synthesize our empirical data from the case with other existing theory, such as theories of learning and complexity. Through this analysis, we develop a revised framework that reconceptualizes the effect of lean on production costs and use it to develop 11 propositions to direct further research. Included among these are propositions about how the timing, scale, and extent of lean implementation can regulate the benefits of lean. Furthermore, when the objective of lean is construed as the provision of value, we propose that this value is an emergent property of a complex process, different from the mere sum of the values provided by its constituent tasks. Therefore, the elimination of tasks will not guarantee cost reduction, and lean may provide even greater value by incorporating some aspects of agile manufacturing. Overall, we develop a fuller range of the effects of lean practices on production costs and illuminate how operations managers might control key variables to draw greater benefits from lean implementation.

A central tenet in the theory of lean production is that the implementation of lean practices will reduce waste and thereby decrease costs. However, not all lean implementations have led to such results. Apparently, this effect is moderated by several factors, potentially even to the point of reversal. It is important to increase our understanding of how this might occur. We believe that a key limitation of most past studies is that they have failed to consider the impact of environmental context or organizational contingencies, which can affect the relationship between lean practices and production cost reduction. For example, White et al. (1999) and Shah and Ward (2003) found that plant size had a significant effect on the implementation of lean practices. This shows that, regardless of establishing what lean is, it remains important to establish how best to become lean in varied contexts. Good theory must address both what and how ( Handfield and Melnyk, 1998), yet lean implementation has so far received much less attention in the scholarly literature. According to Shah and Ward (2003), “There is not only a lack of empirical attention given to contextual factors’ relationship with lean practices, but there is also a paucity of theory to guide our expectations about the direction of possible effects.” Reports of lean implementations in several industries led us to explore the effects of novelty, complexity, instability, and buffering on lean implementation. In an age of increasing product functionality, diversification, customization, and change, novel and complex products are becoming more common, and they account for a significant portion of the economic output of developed countries ( Wallace and Sackett, 1996). In this paper, we look deeper into the mechanisms by which lean affects production costs. An interest in novelty and complexity drew us to conduct an in-depth case study of Lockheed Martin's production system for the F-22, the most sophisticated aircraft ever produced in a flow shop. To build theory, we synthesized the empirical data with other existing theories of complexity and learning to develop a revised framework that reconceptualizes the effect of lean on production costs. This analysis led to 11 propositions which can be tested in future research. In brief, we propose that the timing, scale, and extent of lean implementation matter, and we discuss how. Also, when the objective of lean is conceptualized as the provision of value, we propose that this value is an emergent property of a complex process, different from the mere sum of the values provided by its constituent tasks. Therefore, the elimination of tasks will not guarantee cost reduction, and lean may provide even greater value by incorporating some aspects of agile manufacturing. The remainder of the paper is organized as follows. Section 2 establishes the conventional expectations of lean production, as well as some of the problems, and presents our initial framework for investigation. Section 3 explains our research methodology and site selection, after which Section 4 summarizes the case study data. Section 5 builds theory through a synthesis of the empirical data with extant theory. Section 6 concludes.

Beginning with the central proposition of lean theory, that the implementation of lean principles and practices will reduce production costs, this paper explores the effects of other variables on this relationship. The case study of the F-22 program – an exemplary case of uncertainty and instability driven by novelty and complexity – serves a revelatory role, adding to understanding “by refuting some widely held beliefs” (Stuart et al., 2002). It also provides motivation, inspiration, and illustration of a revised view (Siggelkow, 2007). The synthesis of existing theory with empirical data led to a revised framework that reconceptualizes the relationship between lean and production costs. The number of factors and relationships in the revised framework suggest that lean implementation is not simple and may help explain the mixed results in various organizations. We find that the timing, scale, and extent of lean implementation matter, that the reduction of waste is better construed as the provision of value, and that this value is an emergent property of a process—implying that lean is not the guaranteed result of the elimination of tasks. Certainly, our propositions point to the need for further empirical research, which should in turn result in further enhancements to the theory of lean. Additional study is needed to explore the relative intensities and effects of the proposed relationships. Nevertheless, our revised framework expands theory by significantly reconceptualizing the relationship between lean implementation and production costs and then grounding these predictions with a combination of conceptual arguments, existing theory, and case study evidence. If our analysis has encouraged moving beyond a simple model of lean implementation and its associated heuristics, then it will have served its purpose.