HKSM
Cost of Quality (CoQ)
The total expenditure over the product's entire life tied to quality: what you spend to prevent defects, to check and verify compliance, and what it costs when requirements are not met (both internal and external failures).
Key Points
- CoQ spans the full life cycle: development, delivery, operations, support, and end-of-life.
- It includes cost of conformance (prevention + appraisal) and cost of nonconformance (internal + external failure).
- Investing in prevention and appraisal typically lowers failure costs and overall CoQ.
- Used to justify quality investments and balance short-term spend against long-term savings and risk.
Example
A software project budgets for developer training, code reviews, and automated testing (prevention/appraisal). These actions reduce defect leakage, avoiding expensive rework, customer support, and warranty payouts after release (failure costs), lowering the total CoQ.
PMP Example Question
While planning quality, a project manager weighs added spending on training and inspections against the expected drop in warranty claims and rework. What concept is the PM applying?
- Cost of Quality (CoQ)
- Earned Value Management
- Opportunity Cost
- Value Engineering
Correct Answer: A — Cost of Quality (CoQ)
Explanation: CoQ considers prevention and appraisal costs versus the costs of failures across the product life, guiding investment to minimize total quality-related costs.
