They are not alternatives — they are complementary. ISO 9001 provides the framework and documented foundation. Six Sigma provides the data-driven method for improving specific processes within that framework.
ISO 9001 = the framework and foundationSix Sigma = the improvement methodologyNot alternatives — best used together
Quality & Ops
ISO 9001
International standard for a Quality Management System. Requires documented procedures, monitoring, and continual improvement. Certified by NABCB-accredited CBs.
Quality & Ops
Six Sigma
A data-driven process improvement methodology using DMAIC to reduce defects to 3.4 DPMO. Belt certification through ASQ or IASSC. Not a regulatory requirement — a methodology.
Certification
CB certificate vs individual Belt certificate
Mandatory?
For tenders/buyers vs never mandatory
Scope
Entire organisation vs specific project
Dimension
ISO 9001
Six Sigma
Type
Management system standard — certified
Process improvement methodology — individual cert
Certificate issued by
NABCB-accredited CB (to organisation)
ASQ or IASSC (to individuals)
Mandatory?
For tenders, export, large B2B
Never mandatory
Scope
Entire organisation — all processes
Specific project — one defined problem
Data requirement
Records required — measurement encouraged
Quantitative data essential from the start
Timeline to benefit
3-6 months to certificate
4-16 weeks per DMAIC project
Common question answered
Do you have a quality system?
Why is this defect happening? How do we fix it?
IATF 16949 requirement
Required as prerequisite
Expected capability — auditors ask about it
Most common failure
SOPs not followed in practice
Control phase skipped — improvement reverts
Which one do you actually need?
→ Choose ISO 9001 if
A buyer, tender, or contract requires a quality management certificate
You need a documented, auditable quality system
Your organisation has never had formally documented processes
→ Choose Six Sigma if
You have a specific measurable quality problem to solve
Your processes are documented and you want to improve a specific one
An IATF customer is asking about Six Sigma capability
Individual team members want a recognised quality credential
Can you have both?
Absolutely — the intended combination. ISO 9001 creates the documented process foundation. Six Sigma provides the structured methodology to improve specific processes within it. IATF 16949 explicitly expects both.
Clicarity generates the stage-wise production data that makes Six Sigma Measure phase meaningful. Stage-wise rejection data — quantity rejected and reason code at every step — gives you the baseline DPMO and points to the root cause. After improvement, Clicarity tracks sustained defect rates through the same records. See how it works →