Measurement, or the need for it, is pervasive in software and systems engineering. Yet an understanding of how to best use measurement has remained alltoo uncommon, as has straightforward guidance from the experts. Even experts have difficulty following the sometimes-implicit threads among the measurement-related concepts in many process improvement models and standards. Exhortations to do measurement, without sufficiently elaborating what to do, have not worked exceptionally well in the past. However, there has been an increasing recognition of the importance of focusing explicitly on measurement and analysis. Certain basic ideas must be introduced early and well.