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QA vs QC – Difference between Quality Assurance and Quality Control

About Quality Control – QC

This is the most basic level of quality. It started with activities whose purpose is to control the quality of products or services by finding problems and defects.

At its simplest, QC is inspecting, testing or checking something (service or product) to make sure it’s OK. The intent is to identify anything that isn’t OK, and either fix it or eliminate it, to make sure it conforms to the specifications, and has/does/functions as required. QC is typically done at the end of the line, before it ‘goes out the door’. If the something isn’t OK, this is called ‘nonconformity’ or a nonconforming service/product.
Quality Control does not ensure quality; it only finds instances where quality is missing.

For example:
Product: Marker Pen
Requirement: All markers should have logo as “ABC”.
QC can pinpoint all those markers which don’t have any logo or have wrong logo but it cannot tell you why the manufacturing unit is producing some markers without logo.

Important activities done in QC – Inspection, testing.
QC is only about ‘Corrective measures’.

About Quality Assurance (QA)

Quality Assurance developed from the realization that quality could be improved by looking ‘further up the line’. It is aimed at preventing nonconformities/defects.

QA still has QC at its core to control the quality of service/product, but it goes beyond mere testing or inspection to also consider related activities or processes (such as training, document control and audits) that may be resulting in defects further down the line.

For example:
Think of QC as something like doing periodic checks to see that a horse is still in its stable, whereas QA would aim to make sure that the stable doors and gate locks work properly and that all the stable hands are trained and aware of the need to close and bolt doors properly.