It is commonly believed that the earlier a defect is found the cheaper it is to fix it. The following table shows the cost of fixing the defect depending on the stage it was found. For example, if a problem in the requirements is found only post-release, then it would cost 10–100 times more to fix than if it had already been found by the requirements review.
| Cost to fix a defect | Time detected | |||||
| Requirements | Architecture | Construction | System test | Post-release | ||
| Time introduced | Requirements | 1× | 3× | 5-10× | 10× | 10-100× |
| Architecture | – | 1× | 10× | 15× | 25-100× | |
| Construction | – | – | 1× | 10× | 10-25× | |
