Which statement correctly differentiates quality assurance (QA) and quality control (QC) in manufacturing?

• A. QA tests finished products; QC designs processes.
• B. QA uses marketing data; QC uses customer feedback.
• C. QA focuses on preventing defects in processes; QC involves inspecting and testing outputs.
• D. QA and QC are interchangeable terms.

Answer: (C)

Quality assurance and quality control divide quality work into prevention and inspection. Quality assurance focuses on preventing defects by improving the way products are made—setting up clear procedures, standardizing processes, training people, and monitoring process capability so problems don’t occur. Quality control, on the other hand, checks the outputs—inspecting and testing finished or in‑process products to identify and catch defects before they reach customers.

In practice, QA builds quality into the process; QC verifies the product against specifications. For example, QA might implement a standardized setup of equipment and a routine for preventive maintenance to prevent drift in performance, while QC would sample and test finished parts to ensure they meet tolerances. This distinction is why the statement describing prevention in processes for QA and inspection/testing of outputs for QC best captures their roles.