3.3 The Process of Software Measurement

Sometimes, software developers are very confused as to why they are measuring software. Metrics are dutifully collected and stored about programs, processes, people, and environments. These measures are similar to one-hand clapping - there is no opposing hand to make a sound. When measurements are being used effectively, we will use these measurements to map from one of the four taxonomic measurement domains to another for the purposes of developing predictive models and also for modifying the software development process.

In recent years, the focus of software development has shifted to understanding the software process. We now understand that programs evolve from a process milieu. Just as there is a software development process, there is a corresponding software measurement process. We should not think of measurement as an unpleasant activity that we will do but once and be done with it. Software systems are rapidly developing entities. Their characteristics change over time.

The measurement circumstances are rather like measuring a child. It would be unthinkable to measure the height of a human child at two years and then presume that we now know all there is to know about that person. Human beings grow until they reach maturity. Then, after a period of some years, they begin to shrink again. Programs are similarly dynamic. In their early evolutionary stages, these programs are relatively simple. As time progresses and we begin to get a better handle on just exactly what the customer really wants, these simple programs grow quite complex. As the programs age, unwanted or unused functionalities are trimmed from them and then the programs may become less complex. But the bottom line is that programs are dynamic objects. We must then conceive of a measurement process so that we can understand the program as it is now.