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Glossary of Lean Terms

There are lots of terms in Lean (some Japanese words) what do they mean? 

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A3 or A3 Report – An A3 is a reporting method made popular by Toyota. It requires that an entire message is communicated on a single piece of paper (paper size = A3 or 11”x17” or Tabloid). A3’s fall into one of four types:

  • Problem Solving – Summarizes the all steps of the entire problem-solving effort.

  • Proposal – Summarizes a proposal and next steps of requesting approval. 

  • Status Report – Provides concise summary of the current status, issues and corrective actions for any project or effort. 

  • Informational – Provides a single page summary or explanation of a facility, technology, operation, etc.

The Problem Solving A3 is the most popular and provides and excellent method for briefing stakeholders, ensuring the steps are followed and capturing the knowledge gain so it can be shared with others.   


Andon – A visual management tool that is used to communicate the status of an operation or machine. Andons indicate the current status and are critical in allowing everyone to see if abnormalities (problems) exists. Identifying these abnormalities is critical in being able to address them. 


Bullwhip Effect – The bullwhip effect happens when each level of the supply chain holds and distorts the real demand data. At each level the distortion gets worse and worse until the actual demand is unidentifiable. The distortion of the demand occurs through regular, well intended, business practices like: forecasted ordering, min-max ordering, sales pushes, transportation discounts, volume discount programs, etc. Each of these either create a “dam” in the flow of information or shift the demand to achieve arbitrary targets.

Cycle Time – Is the time it takes to complete a process for a single unit of work. The Cycle Time is best measured through observation and includes all aspects of the current operation, including Value Added and Non-Value-Added work. Engineered time standards are not recommended for calculating accurate Cycle Times.    


FIFO – First In First Out – Is a practice for maintain the proper sequence of operations and materials. Using FIFO promotes a consistent lead time for materials through a process and ensures that material does not become obsolete when queued. Not utilizing FIFO in a process can result in “cherry-picking” by operators and a delay in the discovery of quality issues.   


5S – Workplace Organization – A set of standardized work and visual management practices that organize and optimize the workplace to allow maximum efficiency. The 5 S’s come from five Japanese words that translate as:

  1. Sort (Sieri) – Sorting the essential from the non-essential 

  2. Straighten (Seiton) – Arrange needed items in a neat and easy-to-use manner

  3. Shine (Seiso) - Clean and inspect work area, equipment, and tools

  4. Standardize (Seiketsu) – The practices to maintain the cleanliness and order that result from practice of first three S’s

  5. Sustain (Shitsuke) – The management practice and follow-up to promote and sustain the other four S’s. 

Note, sometimes you will see 4S, because the fifth Sustain becomes redundant with good daily standard work; and sometimes you will see 6S, because one result of 5S is always improved Safety, so some make it the sixth S.  


5 Whys – Is a process for evaluating a problem in a way that moves past the obvious symptoms of the problem to determine the root cause of the problem. The number of why’s required is notional and may not always be five. The principles assist in finding the root cause, because the root cause is almost always a violation of one or more of the Lean Principles. 


Gemba – Is the “actual place”. The place where the work takes place. To understand a problem and to make effective improvements you must go to the workplace to understand.  


Genchi Genbutsu – Translates to “real location, real thing”. In Lean it means to Go Look, Go See, that is to say that to truly understand what is happening in the workplace you have to go and see (observe) the actual work in the workplace.  


Heijunka – Level and Balanced – Is the leveling and balancing of the type and quantity of work that is performed over a given period of time. Heijunka is a critical element of establishing an effective JIT (Just In Time) environment.  


Hoshin Kanri – Policy Deployment – Strategic Planning and Deployment – Is a management process that aligns all the activities of the organization with the strategic objectives of the organization. This process starts as top-down, but then moves through a process of “catch-ball” (iterations between different levels) to negotiate goals and targets that have the support and buy-in of the entire leadership team. Care is taken to make sure the alignment is both horizontal (across departments) and vertical (within the department). The resulting action plans are reviewed regularly, check plan versus actual, to identify issues and corrective action as soon as possible.   


Jidoka – Built-In Quality – Autonomation – Provides machines and operator the ability to detect problems / abnormalities and to immediately stop the operation. By stopping immediately, the problem-solving process can begin immediately, and quality is maintained by not continuing to produce incorrect material. Autonomation allows the machine to detect the problem and stop without human intervention. This allows the machine to operate without being monitored by a worker.  


JIT – Just In Time – Delivering the right part, at the right time, in the exact quantity the customer desires. JIT is a Lean Principle and requires the key elements of heijunka, pull system, takt and continuous flow. 


Kaizen – Continuous Improvement – Is the process on continuously improving a system / process. Typically, two levels of Kaizen have been identified:

  • Process Kaizens focus on individual process and do not expand beyond the immediate suppliers and customers of the process  

  • System or Flow Kaizens focus on the overall value stream or system (collection of processes) 


Kanban – Is a signaling device that indicates a request (demand) to from a customer in a pull system. A Kanban Card is a classic example of a Kanban, but the signaling device can take on many forms. Whatever form, the Kanban indicates an action to be taken.  


Muda, Mura, and Muri – Are the 3 sources of inefficiency which are to be eliminated. 

  • Muda means Waste – Anything that consumes resources but does not add value to the customer. There are seven wastes (see below).

  • Mura means Unevenness – It represents the peaks and valleys within an operation. This can be eliminated by management through level scheduling (see Heijunka). 

  • Muri means Overburdening – This is the overburdening of equipment or people. Overburdening of equipment is obvious, if you put 2 tons on a 1-ton truck it will breakdown. Overburdening of people is less obvious, but equally damaging. When people are overburdened the problems occur in the same pattern, first quality suffers, then safety suffers, and finally sanity / moral suffers.

Optimum Inventory Level (OIL) – OIL is the target inventory for all stock including On Hand, On Order and In Transit. OIL is calculated using average daily demand, order cycle days, lead time days, and safety stock days. OIL is maintained daily by ordering a new minimum order unit every time the total inventory within the supply chain drops below the OIL. As the minimum order unit becomes 1, the effect of selling 1 unit will be buying 1 unit. Each sale pulls an additional unit into the supply chain. 

Over Production – Is producing more or faster than the customer desires. It is the worst of the seven wastes. It is the worst waste because it causes the other wastes and because it is often used to cover up problems (just in case). 


PDCA – Plan Do Check Act – Is the heart of an effective scientific problem-solving process. It is also known as the Deming Wheel (named for W. Edwards Deming founder of the modern quality movement). 

  • Plan– Define the problem, determine the root cause, develop the hypotheses for addressing the root cause

  • Do– Implement the changes in a model area to test the hypotheses

  • Check– Evaluate the result of the test to determine if the hypotheses was correct 

  • Act– Determine the next steps, if successful standardize and sustain the improvements, if not successful return to the Plan step to reevaluate the hypotheses and repeat the process 


Poke Yoke – Error proofing – Is the design of products, tools, equipment or sensors into a process to prevent errors from occurring or being passed to the next step.  


Pull Operation – Is an operation that is controlled and paced by signals of need from downstream activities to the upstream activities. Upstream activities only act when they receive a request signal from the downstream activity. This is a fundamental requirement for a JIT (Just In Time) operating environment.   


Push Operation – Is an operation that is controlled and paced by a forecast or plan to maximize the rate of production. Typically processes produce large batches with little regard of the downstream activities. This attempts to optimizes the efficiency of individual processes, but at the expense of the overall system. The result is a higher overall operating cost. 


Sensei – Is “teacher”. In Lean it is the master (achieved through years of experiences, not book training) that is responsible for developing and coaching leaders so they can coach and develop those in their area of responsibility    


Seven Wastes – Muda – In Lean there are seven recognized wastes. The ideal state is zero waste. By identifying and recognizing these wastes we can continue to move toward the ideal state. 

  • Over Production – producing more or faster than the customer desires, the worst waste of all

  • Inventory – Any WIP (work in process) that is currently not being used or worked on

  • Waiting – Workers waiting for a machine or system to run or waiting for work

  • Motion – The movement of the people doing the work

  • Transport / Conveyance – Moving material more or further than necessary 

  • Over Processing – Performing unnecessary work; doing more than is required by the customer; making the work more complicated than it needs to be 

  • Rework / Errors – The inspection, rework and scraping of output to address poor quality 


SMED – Single Minute Exchange of Die – Is the process of changing over an operation from one type of work to the next with minimum down time. Originally this related the quick (less than 1 minute) changeover of dies, but the concept has been expanded to many types of changeover. This is accomplished by separating the primary / internal activities: those that require the operation to be stopped, from the prep / external activities, from those that can be done while the operation is running.   


Standardized Work – Is the precise procedure for conducting a process. Standardized Work is a Lean Principle. Standardized Work includes three elements:

  • Standard Sequence – The steps and sequence required to successfully complete the process

  • Standard Time – The Cycle Time and Takt Time required to successfully complete the process within a specific window

  • Standard In Process Stock (Inventory) – The standard inventory required between processes (the connection) to allow the processes to operate smoothly  


Takt Time – Pace – Is the German word for tempo / pace. In Lean it represents the pace that it required to meet the demand of customers. It can be calculated by dividing the available processing time (window) by the customer demand for the period (day). 

For example, if we are working 8 hours and the customers need 320 units, you need to produce 1 unit every minute to meet the needed pace. 8 hours = 480 minutes / 320 units means 1 unit every 1.5 minutes.   


TPS – Toyota Production System – Refers to the collection of practices and techniques used within Toyota to create the culture that is commonly referred to as Lean.   


Value – Is the inherent value of a product or service as defined by the customer. The external customer communicates their perception of value through the price they’re willing to pay and demand. 


Value Stream Mapping – Is a Lean tool which maps the flow of material and information required to go from order to delivery. It also documents the value added and non-valued time within these steps. This tool is exceptional in providing insight to time-based problems.  


Visual Management – Is the combined use of tools and indicators that supports all the other elements of Lean by making the normal / expectations visual for all to see, so that problems can be easily identified.


WIP – Work In Process – The inventory that exists within a value stream between the processes. WIP should always be controlled through Standardized Work, Standard In Process Stock.   

Bullwhip Effect
Pull Operation
Takt Time
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