A Hewlett-Packard executive once noted, “If you catch a two cent resistor before you use it and throw it away, you lose two cents. If you don’t find it until it has been soldered into a computer component, it may cost $10 to repair the part. If you don’t catch the component until it is in the computer . . . the expense may exceed the manufacturing cost.”
One of the purposes of quality management is to find errors and defects as early in the project as possible. Therefore, a good quality management process will end up taking more effort hours and cost up-front. However, there will be a large payback as the project progresses. For instance, it is much easier to spot problems with the business requirements during the analysis phase of the project, rather than have to redo work to fix the problems during testing. It is also much cheaper to find a problem with a computer chip when the chip is manufactured, rather than have to replace it when a client brings the computer in for service after a purchase. The project team should try to maintain high quality and low defects during the entire deliverable creation processes, rather than hope to catch and fix problems during the Testing Phase at the end of the project (or worse, have the client find the problem after the project has been completed).
The better approach is to perform quality control and quality assurance throughout the project. You should first strive to prevent as many errors as possible. However, it is also important to catch any errors that are introduced as quickly as possible to minimize the impact of correcting them.