Q12 of 38 · Manual & exploratory
What is the difference between QA and QC?
Short answer
Short answer: QA (Quality Assurance) is process-focused — building activities into the workflow that prevent defects (reviews, standards, training). QC (Quality Control) is product-focused — finding defects in the built artefact through testing.
Detail
Quality Assurance is preventive. It's about the process: code review standards, pair programming, definition-of-done checklists, retrospectives, training, automation infrastructure. The investment is in how the team works so that fewer defects are introduced in the first place. A QA-mature team has lower defect arrival rates because the process catches problems before they become bugs.
Quality Control is detective. It's about the product: testing, inspections, audits — actively looking for defects in artefacts that have been produced. Manual testing, automated test runs, performance testing, and security audits are all QC activities.
Most "QA engineers" or "QA testers" do both. The titles have drifted; in practice, the role often involves designing tests (QC), building automation (mix), advocating for testability (QA), and shaping the team's process (QA).
A team obsessed only with QC always plays catch-up — defects get caught, but only after they're created. A team investing in QA reduces the inflow. The best teams measure both: defect escape rate (QC effectiveness) and defect injection rate (QA effectiveness).