Six Sigma & Lean — Process Improvement Methodologies
Six Sigma and Lean are not certifications you apply for — they are process improvement methodologies your team implements. The result is measurable: lower defect rates, shorter cycle times, less waste. For businesses supplying to large manufacturers or automotive OEMs, demonstrable Six Sigma capability is increasingly a vendor requirement.
DMAIC
Define Measure Analyse Improve Control
No regulator
Methodology, not a licence
Belt levels
Yellow, Green, Black, Master Black Belt
Your company is implementing Six Sigma or Lean and you may be asked to get Belt certified. A Green Belt leads improvement projects within their function. A Black Belt leads cross-functional projects and coaches Green Belts. Yellow Belt is awareness level. All Belt certifications require demonstrating knowledge of the methodology — most also require a completed project.
Yellow Belt
Awareness and team member
Green Belt
Project leader within function
Black Belt
Cross-functional project leader and coach
Quick reference. Six Sigma: DMAIC (improvement) and DMADV/DFSS (design). Belt certification: ASQ (CSSyBB, CSSGB) and IASSC (ICBB, ICGB) are the two globally recognised bodies. Lean: Toyota Production System principles — value, value stream, flow, pull, perfection. Lean Six Sigma combines both. GE, Motorola origins. No mandatory accreditation body.
ASQ / IASSC
Two recognised Belt certification bodies
DMAIC
Improvement methodology
Lean
Waste elimination — Toyota origins
Six Sigma was developed at Motorola in 1986 and popularised by GE under Jack Welch in the 1990s. The name refers to the goal of achieving a defect rate of no more than 3.4 defects per million opportunities — statistically equivalent to six standard deviations from the mean. Lean manufacturing derives from the Toyota Production System developed from the 1940s.
1986
Six Sigma developed at Motorola
TPS
Toyota Production System — Lean origins
DMAIC
Improvement cycle formalised by GE
No regulatory certification body — methodology, not a licenceBelt certification from ASQ or IASSC is the professional standardRequired by many large manufacturers and automotive OEMs
What’s on this page
01 —What it isUnderstanding Six Sigma & Lean
A methodology to reduce defects and eliminate waste — measurable results, no regulatory body required.
Six Sigma is a data-driven process improvement methodology aimed at reducing defects. DMAIC — Define, Measure, Analyse, Improve, Control — is the core improvement cycle applied to existing processes. A Six Sigma process produces no more than 3.4 defects per million opportunities.
Lean manufacturing derives from the Toyota Production System and focuses on eliminating waste (muda) across eight categories: overproduction, waiting, transport, over-processing, inventory, motion, defects, and underutilised talent. Lean Six Sigma combines both — Lean removes waste, Six Sigma reduces variation.
Unlike ISO 9001 or BIS, there is no government regulatory body for Six Sigma or Lean. The methodology is implemented by your team. Belt certification (Yellow, Green, Black, Master Black Belt) is a professional credential — not a business licence. The two globally recognised certification bodies are ASQ (American Society for Quality) and IASSC (International Association for Six Sigma Certification).
Many Indian training providers issue "Six Sigma certificates" with no recognised standing. If your customer or employer asks for Six Sigma certification, confirm whether they require ASQ or IASSC certification specifically. A certificate from an unknown training institute is not equivalent to an ASQ or IASSC Belt.
👥 Illustrative case — details changed for confidentiality
Their scrap rate on a high-volume CNC turning job was running at 4.2% — above their customer's acceptable limit of 2%. A customer audit noted this as a concern.
The challenge
They knew they had a scrap problem but not where in the process it was originating. Scrap was recorded at end-of-line — not stage-by-stage. Root cause analysis was guesswork.
Where Clicarity came in
They deployed Clicarity with rejection reason codes captured at every production stage. Within 6 weeks, the data showed that 73% of scrap originated at the third machining step — a specific machine with a worn spindle. The Six Sigma project used this stage-wise rejection data as the baseline for the Measure phase. The DMAIC project ran for 11 weeks.
The result
Scrap rate reduced to 1.6%. Customer audit concern closed.
We had been guessing at the root cause for months. The stage-wise rejection data from Clicarity showed us exactly where to look.
02 —Who needs itIs it right for you?
Do you actually need it? Honest answer.
✓ You should implement it
Manufacturers with high scrap rates or rework costs
Businesses supplying to automotive OEMs (IATF 16949 expects Six Sigma capability)
Operations with long cycle times or chronic bottlenecks
Service businesses with high error rates or customer complaint volumes
∼ Belt certification worth considering
Quality managers and engineers wanting a globally recognised credential
Professionals in industries where Belt certification is a hiring requirement
— Not what you need right now
Businesses without defined, repeatable processes (implement basic SOPs first)
Very early-stage businesses where process stability hasn't been achieved
03 —What it requiresWhat is checked
The DMAIC cycle — what each phase requires and what it produces.
1
Define — project charter and scope
A written project charter: problem statement, scope, goal, team, timeline, and sponsor sign-off. The project cannot proceed without a clear, agreed charter.
E.g. Problem: scrap rate on CNC turning Job X is 4.2% vs target of 2%. Scope: machining stages 2 to 5. Goal: reduce to below 2% by Q3.Most common failure: Scope too large. Projects that try to fix everything fix nothing. Define phase must produce a focused, measurable problem statement.
2
Measure — baseline data collection
Quantitative measurement of the current process: defect rate, cycle time, DPMO. Includes a Measurement System Analysis (MSA / Gauge R&R) to verify the measurement system itself is reliable.
E.g. 6 weeks of stage-wise rejection data collected. Baseline DPMO calculated. Gauge R&R confirms measurement system acceptable.
3
Analyse — root cause identification
Identify and validate the root causes of the problem using statistical and analytical tools: fishbone diagrams, Pareto analysis, hypothesis testing.
E.g. Pareto chart shows 73% of scrap originates at Stage 3. Hypothesis test confirms correlation with spindle wear on Machine #4.
4
Improve — implement and pilot solutions
Design, test, and implement solutions targeting the validated root causes. Pilot before full-scale deployment.
E.g. Spindle replacement on Machine #4. Pilot run of 500 units shows scrap rate at 1.4%. Approved for full implementation.
5
Control — sustain the improvement
Update the control plan, implement SPC charts, and monitor sustained performance. Hand over to the process owner with documented controls.
E.g. SPC chart for Stage 3 scrap rate. Control limit set. Process owner responsible for monitoring.Most common failure: Control phase skipped or weak. Improvement reverts within 3 months because the control mechanisms were not implemented.
6
Belt certification (for individuals)
For individual professionals: ASQ or IASSC Belt exam. ASQ CSSGB and CSSBB require project demonstration in addition to the written exam.
E.g. ASQ CSSGB: written exam + affidavit of completed project + 3 years of work experience.
What inspectors really check
There is no regulatory audit for Six Sigma. For Belt certification, ASQ and IASSC administer written exams. ASQ additionally requires project affidavits. For IATF 16949 customers, auditors may ask: "Describe a recent Six Sigma project. What was the baseline, what was improved, and how is the improvement being sustained?"
Gap analysis checklist — tick what you already have
Project charter written with problem statement, scope, goal, and sponsor sign-off
Specific, measurable goal with a number.
Baseline data collected with defined measurement method
Stage-wise data, not just end-of-line totals.
MSA / Gauge R&R completed for measurement system
Confirms the measurement itself is reliable.
Root causes validated with data — not assumed
Hypothesis testing or Pareto analysis.
Improvement piloted before full deployment
Pilot data showing improvement before rolling out.
Control plan updated after improvement
Process owner named. SPC chart in place.
30-day sustained performance review documented
Improvement held after project closes.
0 of 7 complete
04 —Official bodyWho certifies in India
Who issues this in India — and how to verify it.
There is no Indian regulatory body for Six Sigma. The two globally recognised Belt certification bodies are:
ASQ — American Society for Quality
CSSGB (Green Belt) and CSSBB (Black Belt). Requires project affidavit + exam. Most widely recognised globally.
Before enrolling in any Six Sigma training: Confirm with your employer or customer whether they require ASQ or IASSC certification specifically. Many training providers issue certificates under their own brand which carry no recognised standing with international employers.
Solution targeting validated root cause. Pilot before full deployment.
Step 5
Control — hand over with controls
Updated control plan, SPC, process owner. 30-day sustained check.
Belt exam
ASQ or IASSC
If pursuing certification: register for ASQ or IASSC exam after completing a project.
▶Where to begin: Use the checklist in Section 3 to assess your readiness before contacting any CB.
DMAIC projects
4 to 16 weeks
Depends on data collection time and scope. Focused projects complete faster.
Belt exam — ASQ CSSGB
Written + project affidavit
Exam + affidavit of completed project + work experience required.
Belt exam — IASSC ICGB
Exam only
No project requirement. Can be taken without prior experience.
Cost
Varies by provider
ASQ and IASSC exam fees published on their websites. Training costs vary widely.
The Control phase is where most Six Sigma projects fail. The improvement is real but within 3-6 months the process reverts to old performance because nobody is monitoring it. The Control phase is not optional — it is where the value is locked in.
06 —Find certified companiesHow to verify
How to find and verify certified organisations.
Six Sigma Belt certifications from ASQ can be verified in the ASQ certified professionals directory. IASSC does not maintain a public directory — verification is through the certificate number issued at the time of examination.
How to verify: To confirm whether any organisation holds a current Six Sigma & Lean certification, use the official register. Verify the issuing CB's accreditation at nabcb.qci.org.in.
Pick one problem, not five — and write a one-page project charter
The most common Six Sigma failure is starting too broad. Pick the single biggest quality or efficiency problem in your operation. Write the charter: what is the problem, what is the measurable goal, who is the sponsor, when does it close.
2
Start collecting stage-wise rejection data today — not end-of-line totals
End-of-line scrap rates tell you there is a problem. Stage-wise data tells you where it is. You cannot run Analyse phase without this.
3
Register for an ASQ or IASSC Belt exam if pursuing individual certification
Choose the level appropriate to your role. Confirm your employer's requirement before registering.
Good records are the foundation. A process tracker builds them automatically.
Clicarity — Live Job Process Tracker & Bottleneck Identifier
Clicarity doesn't run your Six Sigma project. It gives you the stage-wise process data that makes Measure phase meaningful — and the control records that prove your improvements held.
Six Sigma's DMAIC methodology lives or dies on data. The Measure phase requires a baseline — real process data showing where defects occur, at what rate, and at which stage. In Clicarity, every production job captures quantity in, quantity out, rejects, and rejection reason at every stage. That stage-wise data is your Measure phase baseline. The Improve phase uses the same framework to capture post-implementation defect rates by stage. The Control phase uses it to track sustained performance — with the process now split into monitored lines, each tracked independently.
Stage-wise rejection data — quantity rejected and reason code at every production step — gives you the baseline DPMO calculation and root cause direction for Measure and Analyse phases.
When an improvement project splits across two production lines or processes, each is tracked as a sub-job through the DMAIC phases independently. Results from both lines preserved when the project closes.
Control phase monitoring: custom fields at each stage capture the sustained defect rate post-implementation. SPC chart data available from the stage-wise records.
Clicarity shows bottleneck stages — where jobs are held and for how long — which surfaces cycle time waste directly without a separate time study.
📄 Job tracked in Clicarity
#IMP-2026-01 — Lean/Six Sigma improvement project
Define
✎Problem statement
✎Project scope
▼Sponsor
▼Black Belt / Green Belt
📅Target completion
→
Measure
✎Process being measured
#Baseline defect rate (DPMO)
#Baseline cycle time (min)
▼Data collection method
▼MSA completed
→
Analyse
✎Root causes identified
▼Analysis tools used
#Validated root causes
▼Fishbone / FMEA done
▼Data analyst
→
Improve
✎Solutions implemented
▼Pilot conducted
#Pilot defect rate (DPMO)
#Pilot cycle time (min)
▼Approved by sponsor
▼ Job splits — each component tracked independently
#IMP-2026-01-A
Process A — Line 1 improvement
▼Process owner
#Defect rate post
▼Control plan updated
#IMP-2026-01-B
Process B — Line 2 improvement
▼Process owner
#Defect rate post
▼Control plan updated
▲
Components rejoin as #IMP-2026-01 — complete record of every branch, every data point, every sign-off preserved.
Control
✎Control plan updated
▼SPC charts in place
▼Monitoring owner
#Sustained defect rate (DPMO)
📅30-day review date
→
Results review
▼Sponsor sign-off
#Financial benefit (INR)
#Sigma level achieved
▼Project closed
📅Close date
→
Handover to process owner
▼Process owner confirmed
▼Documentation handed over
▼Training completed
▼Project leader sign-off
Wastage tracked:▰ Measure phase: baseline defect rate captured before improvement begins▰ Each process line improved and tracked independently▰ Control phase: sustained defect rate verified 30 days post-implementation
ⓘ Fields and stage names are fully customisable. This illustrates a typical manufacturing improvement project — Six Sigma DMAIC setup.
👥 Illustrative case — details changed for confidentiality
Their scrap rate on a high-volume CNC turning job was running at 4.2% — above their customer's acceptable limit of 2%. A customer audit noted this as a concern.
The challenge
They knew they had a scrap problem but not where in the process it was originating. Scrap was recorded at end-of-line — not stage-by-stage. Root cause analysis was guesswork.
Where Clicarity came in
They deployed Clicarity with rejection reason codes captured at every production stage. Within 6 weeks, the data showed that 73% of scrap originated at the third machining step — a specific machine with a worn spindle. The Six Sigma project used this stage-wise rejection data as the baseline for the Measure phase. The DMAIC project ran for 11 weeks.
The result
Scrap rate reduced to 1.6%. Customer audit concern closed.
We had been guessing at the root cause for months. The stage-wise rejection data from Clicarity showed us exactly where to look.
Clicarity is a process tracking tool. It does not provide certification, consulting, or audit services.