Lean, Six Sigma, Kaizen, Business Process Management and Business Process Reengineering all offer different ways to improve how a business operates.
But choosing a framework should start with the problem you need to solve, not the methodology itself.
If a process contains unnecessary work, Lean may be appropriate. If inconsistent outcomes are driving errors and rework, Six Sigma may be more useful. If teams are making small improvements continuously, Kaizen can provide the structure.
And if the process itself is fundamentally flawed, improving individual steps may not be enough.
The right approach depends on the type of problem, the outcome you need and the scale of change required.
Process improvement frameworks at a glance
| Framework | Best suited to | Primary focus |
|---|---|---|
| Lean | Waste, delays and unnecessary work | Improve flow and remove waste |
| Six Sigma / DMAIC | Errors, defects and variation | Identify root causes and improve consistency |
| Kaizen / PDCA | Small, ongoing inefficiencies | Continuous improvement |
| Business Process Management (BPM) | Complex processes spanning teams and systems | Manage and optimise the end-to-end process |
| Theory of Constraints | Bottlenecks limiting performance | Improve the constraint |
| Business Process Reengineering (BPR) | Fundamentally unsuitable processes | Redesign the process |
What each framework is designed to solve
Lean: remove waste and improve flow
Lean is useful when a process takes more time, effort or resources than it should.
Look for:
- unnecessary steps
- excessive handoffs
- waiting
- duplicate data entry
- unnecessary approvals
- rework
- activities that add little value
The question Lean asks:
Where is the process wasting time or effort?
Six Sigma: reduce variation and defects
Six Sigma is better suited to processes where the outcome is inconsistent.
Use it when:
- error rates are high
- results vary between transactions, teams or locations
- defects and rework are costly
- the root cause is unclear
- performance can be measured with meaningful data
Its DMAIC cycle provides a structured approach:
Define → Measure → Analyse → Improve → Control
Kaizen: make continuous improvement part of operations
Kaizen is suited to businesses where processes are broadly functional but teams regularly identify smaller opportunities to improve them.
It works well when:
- frontline teams understand the problems
- improvements can be made incrementally
- processes need regular refinement
- the organisation wants continuous improvement to become routine
PDCA (Plan, Do, Check, Act) provides a simple cycle for testing and refining changes.
The question Kaizen asks:
What can we improve next, and how do we make that improvement stick?
BPM: understand and manage the end-to-end process
Business Process Management takes a broader view.
It becomes useful when a process crosses departments, systems or locations and individual improvements are not enough to understand the wider problem.
For example, customer onboarding may involve sales, finance, operations, compliance and several business systems.
BPM helps establish:
- how the process actually works
- who owns each stage
- where handoffs occur
- how performance is measured
- where improvement opportunities exist
The question BPM asks:
How does this process work from beginning to end, and how should it be managed?
BPM can also provide the broader structure within which approaches such as Lean, Six Sigma and continuous improvement can be applied.
Theory of constraints: address the bottleneck
Sometimes one part of a process limits the performance of everything around it.
That constraint could be:
- an approval stage
- a specialist team
- a production step
- a system limitation
- a capacity issue
If one stage can process 20 transactions a day while every other stage can process 100, improving the other stages will not solve the underlying problem.
The question is:
What is preventing the overall process from performing better?
How do you choose the right framework?
Start with the business outcome.
Are you trying to:
- reduce processing time?
- reduce operating costs?
- reduce errors or rework?
- increase throughput?
- improve customer response times?
- free staff capacity?
- reduce operational risk?
- support growth without proportionally increasing headcount?
Then identify what is causing the problem.
What does this look like in a mid-market business?
The appropriate approach becomes clearer when the problem is viewed in operational terms.
| Business situation | Starting point |
|---|---|
| Employees repeatedly enter the same information into different systems | Lean + process analysis |
| A process generates frequent errors and rework | Six Sigma |
| Customer onboarding crosses several departments | BPM |
| One approval is consistently delaying the entire workflow | Theory of Constraints |
| Teams regularly identify small operational frustrations | Kaizen |
| A process relies on years of manual workarounds | Reengineering |
| A manual process could be simplified and then automated | Process improvement + automation |
The same business may therefore use different approaches for different processes.
The framework should follow the problem.
See process improvement in practice
Maytech takes a practical, outcome-focused approach to business process improvement, starting with how work actually happens before determining what needs to change.
For example, for McMillans Accounting, Maytech used the client’s existing Microsoft ecosystem to improve its client onboarding process, reducing manual setup time by 80% and saving more than 15 hours each week.
Read the McMillans Accounting case study →
If your business has processes that are consuming unnecessary time, creating rework or limiting capacity, book a free discovery call and we’ll help you find where.
FAQs
Common approaches include Lean, Six Sigma, Kaizen, Business Process Management, Theory of Constraints and Business Process Reengineering. Each addresses different types of process problems.
There is no single best framework. Lean is suited to waste, Six Sigma to variation and defects, Kaizen to continuous improvement, BPM to complex end-to-end processes, and reengineering to fundamentally unsuitable processes.
Consider reengineering when the underlying process is fundamentally unsuitable and incremental improvements are unlikely to address the structural problems.
Yes. Frameworks can complement each other when they address different aspects of the same business problem. The combination should be driven by the problem rather than by a desire to implement multiple methodologies.