As we know, building quality into the software involves cost – I came across a detailed and useful article on “Quality Cost” at LogiGear Newsletter.
Author Rob Pirozzi classifies quality costs into four types: Prevention costs, Appraisal costs, Internal failure costs, and External failure costs. For software practitioners and quality professionals, it is very important to know these four categories of quality cost and decide where to invest most of the efforts to see that the other costs are balanced.
Rob also describes the activities that we typically do for each of these quality cost types. According to Rob,
Prevention costs represent everything a company spends to prevent software errors, documentation errors, and other product-related errors.
Appraisal costs include the money spent on the actual testing activity. Any and all activities associated with searching for errors in the software and associated product materials falls into this category.
Internal failure costs are the costs of coping with errors discovered during development and testing.
External failure costs are the costs of coping with errors discovered after the product is released.
Thanks Rob for a detailed article and analysis done.