Defects adversely affect the functionality of the product; indeed the defective product may be dangerous. A product’s nonconformity is a failure of a characteristic to meet a requirement. Defective products are therefore more serious than other types of product nonconformity.
The gap between the two (defect and nonconformity) is wasteful but a margin of safety is necessary because engineers and clients seek assurance of safety, reliability and durability but both have limited information about the actual performance of materials, structures and subsystems in a wide variety of operating conditions.
Therefore, defect and nonconformity may differ but we treat them the same way in that they must be corrected and that we should learn from them to improve our management systems.
In the continuum from an outcome being defective to perfect, we could diffrenciate quality parameteres along the following lines:
1. Defective – outcomes may injure or kill someone
2. Nonconforming – outcomes fail to meet a requirement and may arise to be a defect.
3. Quality – outcomes fulfill customer requirements
4. Excellent – outcomes exceed the needs of customers
5. Perfect – an ideal many choose to pursue