Building a Lean Case Study: How to Document Success in Your Factory

Introduction — Why Most Improvements Are Forgotten

Many factories improve. Far fewer factories prove they have improved.

Teams reduce lead time, improve flow, eliminate waste, or stabilize quality—but six months later, the gains quietly fade. New leaders arrive. Priorities shift. Tribal knowledge disappears. When someone asks, “What did we actually accomplish?” the answer is vague at best.

This is where Lean case studies matter.

A Lean case study is not marketing material. It is not a victory lap. It is a learning document—one that captures the problem, the thinking, the actions taken, and the results achieved so that improvements can be sustained, repeated, and scaled.

In Efficient: The Proven Steps to Reduce Waste and Increase Profits in Your Business, the tools used to improve processes are also the tools needed to document success properly. This blog explains how to build a practical Lean case study using those tools—without overcomplicating the process.

What a Lean Case Study Is (and Is Not)

A Lean case study answers four simple questions:

What problem were we trying to solve?
What did the process look like before?
What changes were made—and why?
What measurable results were achieved?

It is not:

a list of Lean tools used
a generic success story
a collection of unrelated metrics
a PowerPoint deck with no context

A strong case study tells a clear story, grounded in facts and visuals, that others can learn from.

Step 1 — Define the Problem Clearly

Every good case study starts with a clearly defined problem.

Before improvement, many teams struggle to articulate the real issue. They say things like:

“We’re inefficient”
“We’re always behind”
“Quality is bad”
“People are overloaded”

These statements are symptoms, not problems.

To document success, you must first document reality.

This is where Exercise 4 – Develop Your KPIs becomes valuable—not as a dashboard exercise, but as a framing tool. By defining the few KPIs that truly matter (delivery, quality, efficiency, staffing, or flow), the case study gains focus.

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Example problem statement:

“On-time delivery averaged 78%, driven by unstable flow and frequent shortages at final assembly.”

A clear problem statement becomes the anchor for the entire case study.

Step 2 — Capture the “Before” Condition Visually

Words alone are not enough. Visuals make problems undeniable.

One of the most effective ways to document the starting point is by showing how performance looked before improvement.

This figure is powerful because it contrasts vague or lagging metrics with clear, process-based KPIs. In a case study, this helps readers understand:

what was being measured before
why those metrics were insufficient
how visibility improved after

Additional supporting visuals can include:

cluttered work areas
unclear material storage
inconsistent flow
missing standards

The goal is not to embarrass the team—it is to establish a baseline that makes improvement visible.

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Step 3 — Show How the Process Was Understood

Lean improvements fail when teams jump to solutions without understanding the process.

A strong case study documents how the process was analyzed, not just what was changed.

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This figure shows how ideas are captured during a process walk (Gemba). Including this in a case study demonstrates:

that the team observed the work
that operators were involved
that improvements were based on facts, not assumptions

Supporting this with TASK 1 – Process Walk Improvement Ideas shows that improvement was structured, not reactive.

This step builds credibility. It proves the team did not guess—they learned.

DOWNLOAD YOUR FREE EFFCIENT PROCESS WORKBOOK WITH TASK 1

Step 4 — Explain the Improvements, Not Just the Tools

Many case studies fail because they list tools without explaining why they were used.

Instead of saying:

“We implemented 5S”
“We added Kanban”
“We balanced the line”

A good case study explains:

what problem each change addressed
how it reduced waste
how it made the process easier to manage

Step 5 — Quantify the Results Clearly

Improvement without measurement is opinion.

A Lean case study must clearly show results—especially the ones leadership cares about:

delivery
efficiency
quality
labor utilization

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This figure is especially useful in a case study because it explains how efficiency is calculated, not just the final number. Readers can see:

what changed
why efficiency improved
whether the improvement is sustainable

If quality was a major driver, defect tracking visuals or rework calculations can be added—but keep the total number of figures limited to avoid clutter.

Step 7 — Make the Case Study Easy to Share

A Lean case study should be:

simple
visual
understandable outside the department
usable for training

Avoid jargon. Avoid excessive detail. Focus on clarity.

A well-documented case study can be used to:

train new leaders
justify future improvements
standardize best practices
build confidence in Lean

Common Mistakes to Avoid

When documenting Lean success, avoid these traps:

Too many metrics
No baseline
No visuals
No operator involvement
No explanation of thinking
No follow-up on sustainability

A case study should answer, “Could someone else repeat this?”

If the answer is no, the documentation isn’t complete.

Conclusion — Documenting Success Is Part of the Improvement

Improvement does not end when the numbers go up.
It ends when the learning is captured.

A Lean case study preserves:

the problem
the process
the people’s thinking
the results
the lessons

By using a small number of clear visuals—such as Before & After KPIs, Process Walk Ideas, Process Flow Diagrams, and Efficiency Calculations—and supporting them with structured exercises, teams create a record that lasts longer than the improvement itself.

In Lean, improvement is valuable.
But documented improvement is reusable.

That is how success scales