If prevention costs are invested in engineering work in quality control, what is the expected impact on product defects?

• A. Defects are reduced
• B. Defects increase
• C. Defects stay the same
• D. Defects fluctuate

Answer: (A)

Investing in prevention through engineering work in quality control targets the root causes of defects before they happen. By strengthening design and process controls—such as design reviews, process capability analysis, error-proofing, and robust control plans—the process becomes more stable and capable, reducing variation. With less variation and stronger design in place, the chance of producing nonconforming parts drops, so defects are reduced. In the cost-of-quality framework, prevention not only lowers defect rates but also reduces internal and external failure costs, making the overall quality level higher over time. Occasional defects can still occur from unforeseen factors, but the general effect of prevention is a reduction in defects.