What Is Lean? A Practical Guide to Lean Thinking and Management

If you’ve searched for “Lean methodology,” you’ve probably seen definitions about waste reduction or efficiency. That’s part of it — but Lean is much more than that. It’s a leadership system for building better organizations.

I’ve been studying and practicing Lean since 1994, across healthcare, manufacturing, and service industries — and I’m still learning. That’s one of the most important things to understand about Lean up front: it’s not something you implement and finish. It’s a way of thinking and leading that develops over time.

TL;DR: Lean is a management system focused on improving safety, quality, delivery, and morale by designing better systems and engaging people in continuous improvement. It’s a culture and a philosophy — and a set of methods and practices born from them.

Where Lean Comes From

As I wrote in Lean Hospitals, “countless books have been written on Lean, creating many frameworks and definitions. It is difficult to have a single succinct, yet comprehensive, definition, but we can learn something from each.”

Lean is based on the Toyota Production System (TPS), developed over decades at Toyota. Taiichi Ohno, one of the primary creators of TPS, defined it this way:

“All we are doing is looking at the timeline from the moment a customer gives us an order to the point when we collect the cash. And we are reducing that timeline by removing the non-value-added wastes.”

Ohno’s definition shows Lean to be a time-based approach. Reducing delays leads to better quality and lower costs. Toyota’s website defines TPS as having two technical pillars: “just in time” (improving flow so we provide what’s needed, when it’s needed) and “jidoka” (building in quality at the source). Better flow leads to better quality and vice versa.

The term “Lean Production” was coined by researchers at MIT — including Jim Womack and Dan Jones — in the book The Machine That Changed the World.

The term “Lean” is credited to John Krafcik, a young researcher on the MIT team that produced The Machine That Changed the World. Jim Womack told me the group kept circling back to the word “less” — less time, less effort, less capital, less space, fewer errors — and Krafcik suggested they just call it Lean.

One succinct definition used by instructors at the Lean Enterprise Institute is:

“Lean is a set of concepts, principles, and tools used to create and deliver the most value from the customers’ perspective while consuming the fewest resources and fully utilizing the knowledge and skills of the people performing the work.”

Read more: The Evolution of ‘Lean Production’: Reflecting on 25 Years Since the Term Was Coined

Jamie Bonini, the President of the Toyota Production System Support Center (TSSC), puts it differently:

“We define TPS as an organizational culture of highly engaged people solving problems or innovating to drive performance.”

I like that definition because it starts with people and culture instead of tools. Jamie also describes TPS as mainly a philosophy.

Since Toyota, the same principles have been applied across manufacturing, healthcare, government, banking, software, and startups. The industry changes. The principles hold up.

Where Deming Fits

Lean didn’t come out of nowhere. Toyota learned from W. Edwards Deming, who began teaching Japanese executives and engineers about quality in 1950, and Toyota has been direct about that debt.

His influence shows up in ways that matter more than any tool. Deming taught people to tell the difference between routine variation in a process and a real signal that something changed. He argued that most problems come from the system rather than the people working in it. And he told managers to drive out fear, which is much of what we now call psychological safety.

Read Ohno and Deming side by side and you won’t find identical language. You will find two people more interested in improving the system than in grading the people inside it.

The Two Pillars of Lean

The simplest and possibly most elegant definition of Lean comes from Toyota, in two parts: continuous improvement and respect for people.

Continuous improvement — making small, ongoing changes to processes and systems. At Toyota, this is called kaizen.

Respect for people — leadership behaviors that engage, develop, and challenge every person. This isn’t about “being nice.” It means designing systems where people can succeed, listening to their ideas, and responding to problems without blame.

Ohno described this:

“the most important objective of the Toyota system has been consistently and thoroughly eliminating waste. The concept and the equally important respect for humanity that has passed down from the venerable Sakichi Toyoda are the foundation of the Toyota production system.”

This respect extends to all stakeholders — customers, employees, suppliers, and the communities in which Toyota operates. These principles go hand in hand. Because we respect people, we are driven to improve continuously. Because we respect people, we engage staff, physicians, and patients in the improvement process.

The organizations I’ve seen struggle usually focused on waste elimination and skipped the rest. Leaders don’t get very far by forcing people to change. To be successful, we must focus on both aspects equally.

The Toyota Triangle: Tools, Culture, and Management System

The Toyota Production System is sometimes described as a “triangle” of three integrated elements: philosophy (what we believe), technical tools (what we do), and managerial roles (how we manage) — all focused on people development at the center.

Jamie Bonini explains that the model starts with people because “people are the most valuable resource.” The philosophy has four core points: customer first, people are the most valuable resource, continuous improvement with everyone every day, and shop floor (gemba) focus — go to where the work is done to find and solve problems.

Read more: Toyota Production System Explained: Why Philosophy Matters More Than Tools

That’s the part most organizations skip, and it explains why copying Toyota’s tools without copying its management system doesn’t work. Gary Convis, a retired Toyota senior vice president, wrote that the

“managerial culture for TPS is rooted in several factors, including developing and sustaining a sense of trust, a commitment to involving those affected first, teamwork, equal and fair treatment for all, and finally, fact-based decision making and long-term thinking.”

As a hospital or any organization, you have to make a choice: are you going to implement isolated Lean methods within the context of your existing culture, or are you going to examine what needs to change about your culture?

What Lean Organizations Are Trying to Achieve

The goals of organizations that practice Lean are consistent across industries. They’re working to simultaneously improve Safety, Quality, Delivery, and Cost (SQDC) — with safety always coming first.

Lean is very different from traditional cost-cutting, which is often done by slashing budgets, headcount, and services. Ohno was focusing on flow, not efficiency per se, where efficiency is defined as the ratio of outputs over inputs. Efficiency-based management systems focus on doing more or keeping everybody as busy as possible, which actually interferes with flow. Flow is improved not by working faster, but by reducing waste.

In manufacturing, “delivery” means shipping the right product in the right quantity at the right time. In healthcare, it means providing the right care at the right place at the right time — reducing appointment wait times and delays. Cost improvement comes as a result of better processes, not as a goal pursued by cutting resources.

In Manufacturing and Aerospace:

At GE Aerospace, CEO Larry Culp , who spent more than a decade as CEO of Danaher, where the Danaher Business System was already the operating model, has been leading a Lean transformation rooted in what GE calls “FLIGHT DECK” their proprietary Lean operating system. Culp describes it as “a systematic approach to running our business to deliver exceptional value as measured through the eyes of our customers,” built on leadership behaviors of humility, transparency, and focus.

The results at GE Aerospace have been concrete. One kaizen event at a Lynn, Massachusetts plant reduced build time on the T408 engine from 75 hours to under 32. In other factories, cycle times have been reduced from 240 minutes to 30, and from three months to three weeks. Travel distance for one part was reduced by three miles. These aren’t theoretical — they come from teams on the factory floor improving their own processes.

Culp participates in kaizen events personally, which sets a tone. As one GE leader put it, “When Larry Culp shows up and wants to see how long your material’s been sitting on the factory floor, that simple gesture really sets a tone.” Culp has also been explicit about the cultural shift: “A problem-solving culture is far more effective operationally than a finger-pointing culture.” As Farah Borges, who oversees GE Aerospace’s assembly, test, and maintenance operations, said: “Culture can’t be declared. You have to build it.”

Before GE, Culp built the Danaher Business System during his tenure as CEO, demonstrating that Lean as a management system — not just a set of factory tools — could drive sustained performance across a diversified industrial company. That’s part of why his approach at GE carries weight. It’s how he has run companies for a long time.

GE Aerospace also starts every meeting — including investor events — with safety. Their mantra is “Safety, Quality, Delivery, Cost — in that order.” As Culp says, those words can’t be lip service. Leaders must be willing to let people take actions that put safety and quality first, even at the short-term expense of slower production. And they’ve backed that up by creating an independent Flight Safety Office that reports through engineering, not through the P&L.

Listen to podcasts with manufacturing CEOs:

Jim Lancaster, CEO of Lantech, on “The Work of Management”

Eve Yen, CEO of Diamond Wipes on Manufacturing Close to the Customer

Art Byrne on Lean from the CEO’s Perspective and The Lean Turnaround Answer Book

CEO Gary Michel On Lean For The Enterprise And The Need To Decomplify Work

Drew Greenblatt, President of Marlin Wire on Lean and Competing Against Cheap Chinese Imports

What Lean Looks Like in Practice: Real Results in Healthcare

The five principles from Womack and Jones’s book Lean Thinking remain a practical summary: define value from the customer’s perspective, identify and map value streams, create flow and eliminate waste, establish pull based on demand, and pursue perfection through continuous improvement.

But what does that produce? Here are some outcomes from hospitals that have applied Lean methods, as documented in my book Lean Hospitals:

Allegheny Hospital in Pennsylvania reduced central-line-associated bloodstream infections by 76% and reduced patient deaths from those infections by 95%, saving $1 million.

Denver Health achieved a bottom-line benefit of almost $200 million over seven years while achieving the lowest observed-to-expected mortality among academic health center members of the University Health System Consortium — and they avoided layoffs.

Avera McKennan in South Dakota reduced emergency patient length of stay by 29% and avoided $1.25 million in new emergency department construction.

ThedaCare in Wisconsin reduced patient waiting time for non-emergent orthopedic surgery from 14 weeks to 31 hours — from first call to surgery. Inpatient satisfaction scores improved from 68% “very satisfied” to 90%.

Seattle Children’s Hospital avoided $180 million in capital spending through Lean improvements.

Palo Alto Medical Foundation in California reduced waiting times for screening colonoscopies from six weeks to less than 24 hours while reducing cost per patient by 9.5%.

Presence Health in Illinois reduced sepsis mortality from 24% to 9%, reducing the average cost per case from $15,772 to $12,771.

These came from redesigning systems rather than asking people to work harder. And several of these organizations — including ThedaCare, Denver Health, and Avera McKennan — have formal “no layoffs due to Lean” policies. As ThedaCare’s CEO Dr. Dean Gruner put it, “Nobody would get very enthusiastic about improvement in that world” if people feared losing their jobs.

Listen to podcasts with healthcare CEOs:

Brad Parsons, Hospital CEO & Co-Author of “Creating an Effective Management System”

Grey Dube, Another Lean Healthcare CEO from South Africa

Vance Jackson, a Lean Healthcare CEO from West Virginia

Alan Gleghorn, CEO of Christie Clinic on Lean, Shingo, and Learning from Manufacturing

John Toussaint, MD on CEO Challenges & Enduring Excellence, Lean Leadership, and Shingo

What Lean Is Not

Lean is not about being skinny. It’s not about “cutting to the bone.” Organizations that practice Lean effectively focus on using people’s time and skills more wisely, eliminating wasteful work, and redeploying people to higher-value activities rather than eliminating positions. Lean is probably the best alternative to the old approach of layoffs and cost-cutting.

Lean is not just a set of tools. You can install kanban boards, run kaizen events, and create value stream maps without actually practicing Lean. The tools matter, but only inside a management system that develops people and creates psychological safety. As I wrote in Lean Hospitals, “as a hospital, we have to make a choice: are we going to implement isolated or limited Lean methods within the context of our existing culture, or are we going to examine what needs to change with our culture?”

Lean is not an acronym. It’s not “LEAN.”

Lean is not just for manufacturing. Although Lean originated in factories, the principles apply anywhere work happens. Lean is widely used in healthcare, government, software, and knowledge work. Some hospitals started experimenting with Lean methods in the 1990s. In 2001, the Robert Wood Johnson Foundation searched for healthcare organizations that did things dramatically differently. Their executive vice president said, “We want to see a Toyota in health care.”

Lean is not about making bad stuff faster. Speed is a byproduct of better flow and fewer delays. It’s not the goal.

Lean is not about pressuring people to hit metrics. When organizations turn Lean metrics into targets that people are punished for missing, they get gaming and fear instead of improvement. That’s the opposite of Lean.

Value and Waste

Within Lean, an activity is “value added” if and only if three conditions are met: the customer must be willing to pay for the activity, the activity must change the form, fit, or function of the product or service, and the activity must be done right the first time.

In healthcare, I think of “value” as the work that moves a patient’s care forward — comforting, examining, diagnosing, treating, educating, preventing future illness. Everything else is either necessary support work or waste.

The eight types of waste provide a framework for seeing where time and resources go. But I’d caution against getting too academic about classifying waste types. As I wrote in Lean Hospitals, “rather than arguing for hours about the classification, it is more important to ask if we can eliminate that step or find a better way.”

How Do You Know If Lean Is Working?

This is where a lot of organizations get tripped up. The usual approach is to compare two numbers. Last month to this month, or this quarter to the same quarter last year. Somebody puts a red or green arrow next to it and the meeting moves on.

Two data points don’t tell you much. Every process has routine variation in it, so any two numbers will be different. React to that difference as if it means something and you end up chasing noise. Worse, people learn to explain away numbers instead of improving the work.

A run chart or a process behavior chart with enough history shows you what the process normally does. Then you can ask a better question: did something actually change, or is this the same process doing what it always does?

That matters for the culture, not just the math. When leaders react to noise, people get held accountable for randomness.

Respect for People and Psychological Safety

I visited a hospital that had installed improvement boards on every unit. Months later, most of them were still blank. It wasn’t that people had run out of ideas. More likely they didn’t believe that writing something on a board was safe, or that it would lead to anything. Fear and futility.

When something goes wrong, a Lean response starts by asking what made the error easy to make and hard to catch. Human error isn’t a root cause. It’s a place to start asking about the system.

“Respect for people” is much more complex than it might seem. It’s not a slogan. At Toyota, it means designing systems that help people succeed, involving them in improving their own work, and responding to problems without blame.

The connection to psychological safety is direct. If people don’t feel safe to speak up about problems, point out waste, or admit mistakes, improvement stalls. The tools go unused. The kaizen boards stay empty.

Kim Barnas, former President of the hospitals at ThedaCare, described the shift this way:

“The leader is more of a Zen master. Even if we ‘know’ the answer, our conclusion is less valuable than a team’s investigation into root cause, learning the tools, applying the logic, and applying their own solution. Instead of rapping out answers, we have now become listeners.”

That shift, from telling to listening, is a lot harder than it sounds. It’s also what makes Lean stick. In my experience, the efforts that stall out are the ones where leaders focused on tools, projects, or metrics and left the daily leadership behaviors alone.

Frequently Asked Questions About Lean