They are different functions, and most of the time the combined title is a resourcing decision rather than a misunderstanding. Quality control checks the product itself through inspection, testing, holding and releasing. Quality assurance looks at whether the system making the product can be trusted to get it right without relying on that final check. In a small plant or on a construction project there is rarely budget for both roles, so one person runs the inspection and test plan in the morning and reviews procedures in the afternoon. What I look for on audit is whether that person is ever signing off a release on work where they also designed the controls, because that is where the combined role stops being efficient and starts being a conflict. When you read a QA/QC advert, the duties list usually tells you quickly which of the two the job really is.
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Dilawar Laghari
Auditor, Consultant and Trainer
Audit Workshop
https://auditworkshop.com/------------------------------