Achieving quality in the development process

Quality as applied to a product, either software or hardware, is fitness for use. Products that are fit for use generate satisfaction for the customer and profits for the producer. For the producer, the cost of quality is the sum of the costs to prevent, appraise, and correct defects. Quality must therefore be addressed from the early development stages — specification, design, implementation, and test — through manufacture and distribution. The most important step in preventing defects is to define the right product in the first place. As design proceeds, appraisal techniques further reduce defects, so that in the final stages defect correction is minimal. This article describes the techniques and tools for achieving quality and thus improving productivity and profits.