  While the methodological rigor of computing research has improved
considerably in the past two decades, quantitative software engineering
research is hampered by immature measures and inattention to theory.
Measurement-the principled assignment of numbers to phenomena-is intrinsically
difficult because observation is predicated upon not only theoretical concepts
but also the values and perspective of the research. Despite several previous
attempts to raise awareness of more sophisticated approaches to measurement and
the importance of quantitatively assessing reliability and validity,
measurement issues continue to be widely ignored. The reasons are unknown, but
differences in typical engineering and computer science graduate training
programs (compared to psychology and management, for example) are involved.
This chapter therefore reviews key concepts in the science of measurement and
applies them to software engineering research. A series of exercises for
applying important measurement concepts to the reader's research are included,
and a sample dataset for the reader to try some of the statistical procedures
mentioned is provided.
