(1) Prevention costs are those costs expended in an effort to prevent discrepancies, such as the costs of quality planning, supplier quality surveys, and training programmes.
(2) Appraisal costs are those costs expended in the evaluation of product quality and in the detection of discrepancies, such as the costs of inspection, test, and calibration control.
(3) Failure costs are those costs expended as a result of discrepancies, and are usually divided into two types:
(1) Internal failure costs are costs resulting from discrepancies found prior to delivery of the product to the customer, such as the costs of rework, scrap, and material review.
(2) External failure costs are costs resulting from discrepancies found after delivery of the product to the customer, such as the costs associated with the processing of customer complaints, customer returns, field services, and warranties.