Quality: Prevent the Defect Early, Late Inspection Is Costlier
Preventing a defect costs less than finding it later.
- Prevention — Prevent the defect early, the cheapest
- Appraisal — Finding it during the work
- Internal failure — Rework before delivery
- External failure — A defect reaching the customer, the costliest
Quality management ensures the project meets the agreed requirements. Its core principle: prevention is better than inspection; preventing a defect costs less than finding it later. It distinguishes quality assurance, which improves processes, from quality control, which inspects deliverables. Cost of quality includes cost of conformance, prevention and appraisal, and cost of nonconformance, failures; the later a defect is found, the higher its cost.
Relying on final inspection alone to ensure quality. Prevention during the work is cheaper and more effective.
Prevention is cheaper than appraisal, and appraisal cheaper than failure.
Ready to start serious PMP prep?
Subscribe now →Read the details
Quality management rests on a central principle: build quality into the work as prevention, not extract it by inspection after the fact. Preventing a defect at its source costs far less than finding it later, and far, far less than it reaching the customer. The framework distinguishes quality assurance, improving processes and ensuring they are followed, from quality control, inspecting deliverables to verify conformance. Cost of quality clarifies this logic: cost of conformance covers prevention and appraisal, and cost of nonconformance covers internal failure before delivery and external after it, the latter being the highest in cost and reputational harm. Investing in prevention early saves larger costs later.
Frequently asked questions
Which is better: prevention or inspection?
Prevention; preventing a defect costs less than finding it later.
What is the difference between quality assurance and quality control?
Quality assurance improves processes; quality control inspects deliverables.
What is cost of quality?
Cost of conformance from prevention and appraisal, and cost of nonconformance from failures.
Why is a defect reaching the customer the costliest?
Because it combines rework, compensation, and reputational harm.
What is the goal of quality management?
Ensuring the project meets agreed requirements by building quality into the work.