Quality Prevention versus Detection

Quality cannot be achieved by assessing an already completed product. The aim, therefore, is to prevent quality defects or deficiencies in the first place, and to make the products assessable by quality assurance measures. Some quality assurance measures include structuring the development process with a software development standard and supporting the development process with methods, techniques, and tools. The undetected bugs in the software that caused millions of losses to business have necessitated the growth of independent testing, which is performed by a company other than the developers of the system.

In addition to product assessments, process assessments are essential to a quality management program. Examples include documentation of coding standards, prescription and use of standards, methods, and tools, procedures for data backup, test methodology, change management, defect documentation, and reconciliation.

Quality management decreases production costs because the sooner a defect is located and corrected, the less costly it will be in the long run. With the advent of automated testing tools, although the initial investment can be substantial, the long-term result will be higher-quality products and reduced maintenance costs.

The total cost of effective quality management is the sum of four component costs: prevention, inspection, internal failure, and external failure. Prevention costs consist of actions taken to prevent defects from occurring in the first place. Inspection costs consist of measuring, evaluating, and auditing products or services for conformance to standards and specifications. Internal failure costs are those incurred in fixing defective products before they are delivered. External failure costs consist of the costs of defects discovered after the product has been released. The latter can be devastating because they may damage the organization's reputation or result in the loss of future sales.

The greatest payback is with prevention. Increasing the emphasis on prevention costs reduces the number of defects that go to the customer undetected, improves product quality, and reduces the cost of production and maintenance.