Lean glossary

5 Whys

Asking why a problem happened, then why that cause happened, and so on until you reach a cause you can act on. The number five is a guideline.

5S

Sort, set in order, shine, standardize, sustain

A workplace organization method. It removes what is not needed, gives everything a home, keeps the area clean and makes the standard easy to keep.

8D

Eight disciplines

A team-based problem-solving method in eight steps, from forming a team and containing the problem to verifying permanent corrective actions and recognizing the team. Common for customer complaints and supplier quality issues.

A/B testing

An experiment that shows two or more versions to randomly split groups of users and compares the result on a chosen metric. It replaces opinion with measured behavior.

A3

Named after the paper size

A one-page report that tells the story of a problem: background, current condition, goal, root cause analysis, countermeasures, plan and follow-up. The format forces clear thinking and makes coaching easy.

Actionable metrics

Metrics that link a specific action to a specific result, such as the conversion rate of a cohort after a change. They contrast with vanity metrics, like total sign-ups, that rise regardless of what you do.

Andon

Japanese for paper lantern

Andon is a signal, such as a light, sound or screen alert, that a worker uses to call for help the moment a problem occurs. The goal is to respond fast and solve problems at the source rather than pass them on.

Bottleneck

Constraint

The step with the least capacity, which limits the output of the whole process. Improving any other step does not raise output.

Build-measure-learn

The lean startup feedback loop: build the smallest thing that tests an idea, measure how customers respond and learn whether to persevere or pivot. Eric Ries stresses moving through the loop quickly.

Catchball

The back-and-forth conversation in Hoshin Kanri about goals. Each level discusses its targets with the next, and both sides adjust until they agree.

Cohort analysis

Grouping users by when they started, or by a shared trait, and tracking each group over time. It shows whether changes improve retention and behavior for new users.

Control chart

A time-ordered chart of a measure with control limits. It shows when a process has changed rather than varied as usual.

Cumulative flow diagram

CFD

A stacked area chart showing how many items are in each workflow state over time. Widening bands reveal growing work in progress and bottlenecks; the slope of the done band shows throughput.

Customer discovery

Talking with potential customers to understand their problems, current behavior and what they already pay for, before building a solution.

Cycle time

In flow-based knowledge work, the time an item takes from when work starts to when it is finished. In manufacturing, it often means the time to complete one unit at a process step. Always state which definition you use.

DMAIC

Define, measure, analyze, improve, control

The five-phase structure of most Six Sigma improvement projects. Each phase ends with a review before the team moves on.

DPMO

Defects per million opportunities

The number of defects divided by the total opportunities for a defect, scaled to one million. It is the basis for calculating a process sigma level.

Fishbone diagram

Ishikawa or cause-and-effect diagram

A diagram that sorts possible causes of a problem into categories such as people, method, machine, material, measurement and environment. It helps teams list causes widely before choosing which ones to test.

FMEA

Failure mode and effects analysis

A structured review of how a design or process could fail, how serious each failure would be and which risks need action first.

Gemba

Japanese for the real place

The place where value is created, such as the shop floor, the warehouse or the code base. A gemba walk means going there to observe, ask questions and learn rather than managing from reports.

Genchi genbutsu

Go and see

Going to the place where the work happens to see the facts for yourself, rather than relying on reports.

Hansei

Reflection

Honest reflection on what went wrong and what to do differently next time. Retrospectives and reflection meetings apply it.

Heijunka

Production leveling

Heijunka means leveling the type and quantity of production over time, so demand peaks do not ripple through the process. It reduces inventory and makes work more predictable.

Hoshin Kanri

Policy or strategy deployment

A method for choosing a few breakthrough objectives and aligning every level behind them. Regular reviews add countermeasures when results fall behind plan.

Jidoka

Automation with a human touch

Building in quality by stopping the process as soon as an abnormality occurs. Defects are not passed on, and the cause can be fixed.

Jobs to be done

JTBD

A way of understanding customers by the progress they are trying to make in a situation, rather than by their demographics. People hire products to get a job done.

Just in time

JIT

Just in time (JIT) means producing and delivering exactly what is needed, when it is needed and in the amount needed. Along with jidoka, it is one of the two pillars of the Toyota Production System.

Kaikaku

Radical change

Large, rapid change to a process or system, as opposed to the small steps of kaizen.

Kaizen

Japanese for change for the better

Kaizen means change for the better. In lean it is continuous, incremental improvement by everyone, every day. It also refers to kaizen events: focused workshops that improve one process in a few days.

Kamishibai board

A card-based audit board. Leaders pick cards at random and check that a standard is being followed.

Kanban

Japanese for signboard

A method for managing flow by visualizing work, limiting work in progress and pulling new work only when there is capacity. In manufacturing, a kanban is the card or signal that authorizes production or replenishment.

Layered process audit

LPA

Short, frequent checks of critical process steps carried out by several levels of the organization on a rotating schedule. They verify standards are followed and show leaders the reality of the work.

Lead time

The total time from a customer request to delivery, including all waiting. Customers experience lead time directly, so value stream maps track it closely.

Leader standard work

A defined routine for supervisors and managers, such as gemba walks, board reviews and coaching. It keeps the management system running.

Lean

Lean means creating more value for customers with less waste. It grew from the Toyota Production System and rests on value, flow, pull and continuous improvement.

Lean Canvas

The Lean Canvas is a one-page business model for startups, created by Ash Maurya from the Business Model Canvas. Its boxes cover problem, segments, value proposition, solution, channels, revenue, costs, key metrics and unfair advantage.

Line balancing

Distributing work elements across stations so each one has a similar amount of work, at or below takt time. It reduces waiting and makes the line able to meet demand.

Little's Law

Average work in progress equals average throughput multiplied by average cycle time. It explains why reducing work in progress shortens cycle times when throughput stays the same.

Minimum viable product

MVP

MVP stands for minimum viable product: the smallest product or experiment that lets a team learn whether its riskiest assumption is true. Its purpose is learning, so it is different from a cheaper first release.

Monte Carlo forecasting

Running thousands of simulations based on historical throughput to produce a range of likely completion dates or quantities, each with a probability.

Muda

The eight wastes

Muda means waste: activity that consumes resources without adding value for the customer. Taiichi Ohno listed seven wastes. Many practitioners add unused talent as an eighth.

Mura

Unevenness

Mura means unevenness in the flow of work, such as orders bunched at month end. Mura often causes muri and muda.

Muri

Overburden

Muri means overburden: loading people or equipment beyond what they can sustain, such as running a machine past its rated speed.

Nemawashi

Laying the groundwork

Building consensus before a decision by talking with the people affected and gathering their input one by one.

Obeya

Big room

A room where a project or leadership team keeps its key information on the walls. Decisions happen with everyone looking at the same facts.

OEE

Overall equipment effectiveness

Availability multiplied by performance multiplied by quality. It shows how much of the planned production time was productive, and which losses are biggest.

OKR

Objectives and key results

A goal-setting framework that pairs a qualitative objective with a few measurable key results. Often set quarterly and shared openly across the organization.

One-piece flow

Continuous flow

Moving items through a process one at a time, or in very small batches, without waiting between steps.

PDCA

Plan, do, check, act

The scientific improvement cycle that lean is built on. Plan a change from a hypothesis, do it on a small scale, check the result, then standardize or try again.

Pivot

In business, a pivot is a structured change of direction in a startup. It keeps what has been learned and changes one element of the business model, such as the customer segment.

Poka-yoke

Mistake-proofing

A design or device that prevents a mistake from happening, or makes it obvious immediately, such as a part that only fits one way. Shigeo Shingo developed the approach.

Process capability

Cp and Cpk

A comparison of a stable process's natural variation with its specification limits. Cpk also accounts for how well the process is centered.

Pull system

A system where downstream demand triggers upstream work, instead of upstream processes pushing work based on a forecast. It limits inventory and work in progress.

SIPOC

Suppliers, inputs, process, outputs, customers

A one-page, high-level view of a process used to set scope, often in the Define phase of DMAIC.

Six big losses

The common causes of lost equipment productivity: breakdowns, setup and adjustments, small stops, reduced speed, startup rejects and production rejects. Seiichi Nakajima described them in his work on TPM, and they map onto the three OEE factors.

Six Sigma

Six Sigma is a data-driven method for reducing variation and defects. The name refers to a process with six standard deviations between its mean and the nearest specification limit. Projects usually follow DMAIC, and it is often combined with lean as Lean Six Sigma.

SMED

Single-minute exchange of die

Shigeo Shingo's method for cutting changeover time. It separates internal steps (machine stopped) from external steps (machine running), then simplifies both.

Smoke test

A test of demand before a product exists, such as a landing page with a pre-order button. It shows whether people take real action.

Spaghetti diagram

A map of the path a person or item travels through a work area. Long, tangled lines show wasted motion and transport.

SPC

Statistical process control

Using control charts to monitor a process over time and tell normal variation apart from signals that need action.

SQDC metrics

Safety, quality, delivery, cost

A common set of headings for the key performance indicators on daily management boards. Some teams add people or morale as a fifth heading.

Standard work

The current agreed way to do a job, defined by takt time, work sequence and standard work in process. It is the baseline that makes problems visible and improvement possible.

Supermarket

A controlled store of parts between processes. Downstream processes withdraw what they need, and each withdrawal signals upstream to replenish.

Takt time

From the German Takt, beat

Available working time divided by customer demand. It sets the pace a process must work at to meet demand without overproducing.

Throughput

The number of work items finished per unit of time, such as items per week. Together with work in progress and cycle time, it is one of the core flow metrics.

Tiered meetings

A cascade of short daily meetings at each level of the organization. Problems a level cannot solve go quickly to the next level up.

Toyota Production System

TPS

Toyota's production approach, built on two pillars: just-in-time and jidoka. Lean thinking grew from it.

TPM

Total productive maintenance

A shared approach to equipment care in which operators, maintenance and engineering work together to prevent breakdowns, small stops and defects.

TWI

Training Within Industry

A structured program for supervisors covering job instruction, job methods and job relations. Its job instruction method is a common way to teach standard work.

Validated learning

Progress measured by what a team has learned through experiments with real customers, rather than by features shipped or plans written.

Value stream

All the steps, both value-adding and not, that bring a product or service from request to delivery to the customer.

Value stream mapping

VSM

Drawing the material and information flow for a product family, with times and inventory, to find waste and design a better future state.

Value-added time

Time spent on work the customer would pay for, such as shaping or assembling a product. Everything else in the lead time is non-value-added.

Visual management

Making the status of work, standards and problems visible at a glance, so anyone can see whether things are normal or abnormal.

WIP limits

Work-in-progress limits

Explicit caps on how many items can be in a workflow step at once. They force the team to finish work before starting more, which shortens cycle times.

X-matrix

A one-page Hoshin Kanri planning tool that links long-term objectives, annual objectives, improvement priorities, metrics and owners in a single grid.

Yamazumi chart

Japanese for stack up

A stacked bar chart of the work content at each station, split into value-added and non-value-added work and compared with takt time.

Yokoten

Sharing sideways

Spreading a proven improvement to other areas, lines or sites, so each does not have to solve the same problem again.