Therefore, the attributes of software are less tangible and are more open to debate than the attributes of a physical entity. It is apparent that these are the extreme ends of the spectrum, and somewhere between the two extremes lies an appropriate solution. The crux of the matter is that without instrumentation, the collection of the data becomes intrusive. If there is no compelling reason to collect such data, the quality of the data collection will suffer. The goal of analysis is the identification of patterns.
Patterns imply consistency, and consistency implies process.
Numerical and statistical analysis is the science of recognizing and establishing pattern in data even when the pattern is hidden by random background noise. It should be recognized, however, that the analysis of software metrics is by nature subjective. Projects rarely are the subject of formal experimental design such that all sources of variation can be accounted for. Therefore, no metric can be interpreted without understanding the system from which it originated. So although it is necessary that data apportion the belief, the numbers cannot stand alone.