When you can measure what you are speaking about and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind: it may be the beginnings of knowledge but you have scarcely in your thoughts advanced to the stage of Science.—Lord Kelvin (1883)
Science, which includes software, is based on measurement. To design or redesign software, we need to understand some numerical relationships or metrics. Design for six sigma (DFSS) is no exception. Six Sigma and DFSS live and die on metrics definition, measurement, classification, optimization, and verification.
A software metric is a measure of some property of a piece of software code or its specifications. As quantitative methods have proved so powerful in other sciences, computer science practitioners and theoreticians have worked hard to bring similar measurement approaches to software development.
What is "software measurement?" The software measurement process is that portion of the DFSS software process that provides for the identification, definition, collection, and analysis of measures that are used to understand, evaluate, predict, or control software development (design/redesign) processes or products. The primary purpose of measurement is to provide insight into software processes and products so that an organization can better ...