A lean view of lean

We would like to express our deepest gratitude Wally Hopp, Mark Spearman, and the eight commentators—all luminaries in Lean—for their excellent Forum articles (Hopp & Spearman 2021, hereinafter, source “A”; Cusumano et al. “B”). These have stimulated thinking encouraged rich debate community. Over past 40 years, Lean Toyota Production System (TPS) from which it originated sourced much of research on how manage, improve, connect operations. What began as a term chosen highlight some salient characteristics TPS has evolved into broad description everything that improves operations management (OM). Yet, despite decades effort, two show scholars still do not agree what is. Should there be difference between operational excellence (a general ideal) particular way achieve under circumstances)? When anything OM inter-operational connections is classified Lean, we lose sight key tradeoffs underlie competitive advantage? How reconcile with new appreciation value “fat”—capacity or inventory buffers held protect against variability extreme events—under current increase recognition resilience community? Proponents claim over even apart TPS—but, its evolution, when does outgrow name? In this editorial aim provocative “stir waters,” seeking direct deploy energy generated by exciting conversation started these agenda. Both us worked closely for most careers. Suzanne her doctorate at Harvard Business School (HBS) 1982 intention studying decision theory. She took course Professor Bob Hayes just shock success hit academic world. The excitement trying understand about led highly counterintuitive surprising global advantage switch field OM. At time, insights discussed included understanding importance shop-floor operators quality successful OM—and essential role plays competitiveness. Hall's Zero Inventories (Hall, 1983) had yet been published, but photocopy an early version was being actively entire HBS department. Schonberger's Japanese Manufacturing Techniques (1982) published. recently published “Why Factories Work” (Hayes, 1981). There keen awareness observed could explained strategy theory, urgent sensemaking organized around idea producing time (JIT), usually considered conjunction Total Quality Management (TQM). Much discussion centered culture, whether ability produce JIT close-to-perfect achieved outside Japan. Schonberger (1982), Hall (1983), Monden (1983) prioritized reduction in-process causes one workstation block starve another (see figures 2 3 complete explanation proposed causal mechanisms, p. 26). Suzanne's focused exploratory stress: such line stoppage expected lead process improvement, cause lost production—or worse, discouragement demotivation? Proposing theory relationship stoppages learning required propose definition system permitted determination given not. While all systems seek deliver (not late), unique sets objective neither late nor early. A thus defined (de Treville, 1987) “flow-control” mechanism prevents production absence downstream signal. Later decade, production, publication Machine Changed World (Womack al., 1990) stemming International Motor Vehicle Program (IMVP) Massachusetts Institute Technology (MIT). relative IMVP MIT, Aircraft (later, Aerospace) Initiative (LAI), launched Tyson's career. Like IMVP, LAI also book (Murman 2002). supported Tyson throughout his graduate studies mid-1990s provided him access sponsor companies data foundational both master's doctoral theses. observe applied Boeing, General Electric, Lockheed Martin, Northrop Grumman, Raytheon, Texas Instruments. During he part Product Development Focus Group—one five within LAI—exploring questions might apply context. on, assistant professor, opportunity study implementation F-22 program paper journal (Browning Heath, 2009). Thus, witnessed firsthand power practices marshal resources important applications. That said, industry experiences other couple clear picture failure set formal concepts are precisely can impede communication. weaknesses effective topic. Our intent map out path conceptual elements commonly ascribed following rules Wacker (2004). then revisit cited Lean—Shah Ward (2003)—to explicate contribution explore work done foundation rigorous development. This analysis lets toward (1) identifying, rigorously defining, exploring attributes excellence, (2) disambiguating (3) distinguishing captures (i) (ii) exploration—pre-theory—that underlies philosophy. Hopp (A, 612) stated “Almost everyone focuses primarily efficiency” proceeded “equate efficiency regard increases delivering products practice.” commentators (in B) exception equating solely efficiency. apparent disagreement recalls initial insight simplistic maximizing output ignored losses goods were needed defective. Of course, myopic pursuit taken too far (Lawson, 2001), clearly problematic. Short-term improved expense long-term Indeed, characterized enigma (Kanigel, 1997). Therefore, “efficiency” requires disambiguation respect targeted horizon use. (B, 628) Netland 636) noted Krafcik's (1988) use “lean” rather than “fragile” describe aspect phenomenon. Dictionary definitions adjective invariably include terms “lacking” “deficient”—terms negative connotation many contexts. On side, conceptions “Lean thinking” customer (Holweg, 2007; Womack Jones, 2003). But waste add value, focus often reverts 612), removal “non-value-adding activities.” Hence, review literature 2009, 25) concluded Lean's hallmark characteristic minimization, conclusion agreement 630). “waste” too. Despite connotations denotations itself, proponents want minimization “value maximization,” where getting leaner may require adding removing activities (Browning, Covid-19 pandemic major events stress-tested supply chains, exposing lack resiliency excessive brittleness. It uncommon hear state more situations justified “true” “evolved” Lean. Justified? Probably. However, offered “get Leaner” suggests become misleading unhelpful. concept promising follow, because function effectiveness—that is, minimal sacrifices maximal benefits 630) called “a creating fewer less waste”—that efficiently. component separate it, allows stakeholders make sacrifices. phrase “creating efficiently” keeps efficiency, already contributes determining (along effectiveness). moves closer basic productivity, ambiguity own (e.g., Adler Shah Holweg 633) quoted Ohno's expression providing “maximum minimum input,” essentially goal hardly novel TPS. Excellent always productivity 2020), so cannot claimed unique, Lean—unless, connotes denotes, emphasis increasing improvements must “value” list vicinity need disambiguation. equated it. various processes situations, variabilities consequential outcomes others, leads risk. context product-development projects, explored risk type “anti-value”—for example, portion project's put threatening uncertainties 2019; Browning perspective illustrates types supposedly non-value-adding activities, product design testing, fact useful information reduces project meeting goals. whenever incorporate uncertainty methods, should eventually confront behavioral phenomena attitudes biases (some mentioned discussing fourth lens, A, 620) well subjective aspects value. ask, “Value whom?” tended take customer-centric view Ideally, customers receive satisfactory service, immediately, free. Firms approached ideal internet firms allowing free downloads software) gone business, revenues cover costs employees, supplies, investors—all while operating ways meet social governmental expectations. modest subset employee-oriented TPS's “respect people” (Sugimori 1977). beyond and/or enterprises provide appropriate balance stakeholders, long 2003; Honour, 2008; 2019). Given stakeholders' competing propositions, easier said done. Yet again, challenge operations, otherwise.11 “In case protection low probability optimal profit-maximizing sub-optimal society. settings very nuanced problem [to] moderate weight lean/efficiency chains serve Doing preserves markets big challenge. it's face if better prepared next one.” 2021) Many textbooks discuss before they Providing again concept, distinguishes addressed broadly enough. Beyond contexts, during working industry, problems caused reductionist (vs. view, below), including passionate debates “value-adding.” realize intrinsic property individual emergent overall actions interactions (i.e., process): value-adding activity fed bad inputs will outputs. situation especially acute only inputs—information proxied assumptions (albeit imperfect). If later invalidated, happens activity's added? concluded: cases, stems doing unnecessary necessary wrong (and having redo them)” 2003, 51, original). actual output—products, services, deliverables, information—not execution, inputs—products, information, assumptions—used create depends network (Spear Bowen, 1999)—that process. Viewing therefore essential, higher levels organizations 2020; 2006), truly move excellence. practical however, improvement illuminated seems orient question, “What stop doing?” Taking activity-level prompted short-sighted, non-systems-thinking shortcuts reduction—what “liposuction” “cutting fat,” activities), resulting “emaciation” Lean—but nonetheless driven Sanders, 2012). Several identified occasions organizations' unifying pushed those efforts unhelpful directions overemphasizing certain dogmas, heuristics, practices. Taken far, itself wasteful 2009; Cusumano, 1994; Nobeoka, 1998). Health comes proper diet exercise muscle healthy fat. Spearman's lenses means manage operation effectively, regardless applies. Their Process Lens renamed “Activity Lens,” activities. admit stating, “this lens helpful identifying propagates parts process” 614)—that account Then, Network “Process emphasizes thinking, thereby connecting works Goldratt 2004), eliminating excess capacity) non-bottleneck actually makes productive. counter-intuitive results justify system/process reductionist, activity-by-activity perspective—but predate positive context: Variability needs buffered, either capacity. variability, eliminate buffers. exemplified Section 3.1 comparing identify bottleneck through starvation blocking results, minimize bottleneck's blocked starved Goldratt's constraints (TOC) (Goldratt Cox, 2004). Under TOC, bottlenecks typically first reducing inventories observing tell-tale pile awaiting processing. buffer recommended TOC approach avoid loss capacity (mis)categorized lens. Initially, “explicitly derived from” “equated … with” 610). “the underlying philosophy TPS” “True North” Lean—the guidance defining concepts. 635) described once “synonymous saw generally “multifaceted phenomenon” 630), expanding (1990) facets (fulfillment, supplier management, development, management) went buffering-variability tradeoff production. Other highlighted 1977), although did initially same Toyota. though TPS, became descriptor entirety ensuing decades. typify post-TPS point variants best understood away attachment stand-alone theories, principles, practices, tools times? originally deployed capture permits reduced buffering. Spear Bowen (1999, 104) temporary “countermeasures.” used original sense inappropriate profit, priority. Productivity improve conditions stability, predictability, certainty. inside protected bubbles (such horizons heijunka) benefit majority world includes instability, unpredictability, uncertainty—in supply, demand, them, currently longer term. removed buffered. One another, adds costs. Those up different contexts inventory; purchasing options insurance, hedging; transfer (deliberately unwittingly) stakeholders; worker managerial attention. Are worth benefits? value? Buffering appropriately accommodates strategic provides “healthy fat” satisfy objectives. allow evolve any measure performance Leaner—where fat leanness—we arrive obvious contradiction (at least people, academicians). requiring delineates seemingly similar concepts, differences programs readily apparent. For TQM, JIT, lean manufacturing, continuous share testing each upon exactly uniquely conceptually defined. Overlap using vague ambiguous causing empirical questionable. Put formally, match (Bunge, 1967). consider ‘philosophy’ sometimes production/operations (JIT philosophy, TQM etc.). broadens definition's unspecified properties, leaving denotation unchanged. broadening ‘concept stretching’ (Osigweh, 1989). examples expansion definitions. example ‘big’ just-in-time ‘little’ just-in-time. ‘Little’ ‘more narrowly scheduling service response needed’ (Chase 1998, 324). hand, ‘Big (often production) seeks firm's human relationship, vendor technology, materials inventories’ Although clarity difficulties, second prohibit non-value Consequently, organizational specific cause, ‘philosophy JIT’. With ‘good’ ‘bad’ JIT. claims without giving relationships reductions waste. since violates uniqueness falsifiability virtues Additionally, internal consistency virtue specify ‘how’ ‘why’ reduction. Wacker's recommendations practice. ask: Lean? phenomenon? An ideal? philosophy? thinking? collection practices? strategy? Widespread lacking. “broader operations” 636). 631) “highly adaptive,” application likely failed cases. Probably so… here. All adaptive, misapplication 634) tendency adapt, particularly applications maintaining productivity. properly defined, And detach suggested (focusing instead e.g., Tesla, popular phenomenon), call Is attributable Questions nature limitations important. appreciate pragmatic, “any elevates practice deepens elevate good” 611), because, elevating deepening obviously good, putting label merely confusion. Yes, evolution start exploration considering three alternatives TPS: seru (Yin 2017), Quick Response (Suri, pre-Lean space arriving West, emerged, competitors. Flexible manufacturing receiving considerable Cellular Kone non-TPS objectives flow, assembly lines 1987). TOC—as Goal (2004), 1984—proposed alternative seen stress. contrast JIT's systematic encourage balancing calls batch sizes reveal bottlenecks.22 Note batch-size begins system-wide setup times inventory, highlights flow time. approaches built dynamics protocols logic. Managers choose alleviate identified, prevent starved. uses stress, differ. implementer turn reduce bottleneck—even times, prioritizing bottlenecks. More generally, builds bottlenecks, whereas them step line. shows Jonah claiming bring plant bankruptcy, directly challenging 1990s Sony Canon sought advice expert Japan adjust rapid proliferation volatile consumer demand. leave responsiveness. As Yin (2017), advised right He created (the word biological cell). seru, assembly, packaging carried small, general-purpose machines wheels. Cells configured orders. (2017) replacement large, automated (highly efficient high-volume machines, responsiveness dramatic profit supporting innovation. powerful intervention departure Which Leaner? Attempting answer question distracts fundamental capital investment automation offer advantages engineered order, repetitive TPS—and made heijunka level Suri (1998, pp. 227–243) argued engineered-to-order fits poorly typical system. establishing “pull system” TPS) accurately push place (kanban) limit buildup inventories. suppose kanbans adjacent workstations. upstream soon