QA vs QC — what's the difference?
In one line: Quality Assurance (QA) prevents defects; Quality Control (QC) catches them. QA is about the process — building systems so bad units don’t get made in the first place. QC is about the product — checking the actual goods to find the bad units before they ship. They’re not rivals. You need both.
QA vs QC, side by side
| QA — Quality Assurance | QC — Quality Control | |
|---|---|---|
| Focus | The process | The product |
| Goal | Prevent defects | Detect defects |
| When | Throughout, before production | At checkpoints, during/after production |
| Examples | Supplier audits, QMS, process control, training | Inspections, AQL sampling, lab testing |
| Mindset | Proactive | Reactive |
Why you need both — and where a sourcing agent fits
QA without QC means a great system on paper that you never actually verify. QC without QA means you catch defects again and again but never fix why they happen. Together they close the loop. Here’s how it maps to real sourcing:
QA → Factory Audit
Check the supplier’s systems and capability before you commit.
QC → Product Inspection
Check the actual goods against spec and AQL before you pay.
A good sourcing agent runs both: audit the system, inspect the output.
Frequently asked questions
QA (quality assurance) is process-focused and prevents defects; QC (quality control) is product-focused and detects defects. QA builds the system; QC checks the output.
Neither alone is enough. QA stops problems at the source; QC catches the ones that slip through. Strong programs use both.
A factory audit is QA — it checks the supplier’s capability and systems. A product inspection is QC — it checks the actual goods.
Stuck on a factory's MOQ?
A sourcing agent with volume can often get it lowered.