Key takeaways
Short answer: Cost of quality is the total of what you spend preventing defects, appraising for them, and dealing with failures. Cost of poor quality is just the failure slice — scrap, rework, returns, warranty, lost customers. The reframe: a dollar of prevention typically saves many dollars of poor-quality cost, and most of that poor-quality cost is hidden. See also scrap vs rework.
Cost of quality (CoQ) is conventionally split into four categories. The first two are what you spend to get quality; the last two are what poor quality costs you.
Internal and external failure costs (the cost of poor quality, CoPQ) are pure waste — they buy nothing. External failure especially carries hidden cost: reputation, lost repeat business, and the capacity consumed making, scrapping and remaking the same part. It is the iceberg beneath the visible scrap line.
A plant tracks scrap at €200k a year and feels its quality cost is manageable. A full cost-of-quality view tells a different story: €200k scrap, but also €350k of rework labour, €180k of warranty claims, and an appraisal team of four spending most of their time inspecting — well over €1m of CoPQ, most of it never attributed to quality. Against that, the €80k it would take to mistake-proof the top three defects looks like the obvious investment. The reframe turned an "acceptable" scrap number into a clear case for prevention.
Investment in prevention reduces both appraisal and failure costs. Most mature quality programs find prevention spending pays back several times over in avoided CoPQ — which is why the cost-of-quality lens so often flips the budget conversation from "cut inspection" to "invest in prevention."
Most plants track scrap but not the full CoPQ. Surfacing appraisal load, warranty and capacity lost to rework reveals the true cost and justifies prevention investment that a scrap-only view would never support.
1. Tracking scrap only. Most of the real cost of poor quality stays hidden.
2. Cutting appraisal to save money. Without prevention, less inspection just lets more failures escape.
3. Ignoring capacity lost to rework. Rework hours are real CoPQ that rarely gets booked.
4. No prevention budget. Paying failure cost forever instead of investing to remove it.
CoPQ shows up in the OEE Quality rate as scrap and rework. Improving quality-at-source cuts CoPQ and lifts OEE simultaneously — the same prevention investment that lowers cost also raises the Quality term.
Fabrico tracks defects with reason codes and surfaces scrap and rework, giving you the data to quantify CoPQ and justify prevention. Book a demo to see your quality losses costed.
Yes — CoPQ is the failure portion of total cost of quality.
Prevention — it reduces both appraisal and failure cost.
Scrap alone hides most of the real cost — rework, warranty and lost capacity.
CoPQ is the Quality losses in OEE; cutting it lifts the Quality term.
Often several times over, in avoided scrap, rework, warranty and inspection.
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