Chapter 1: Software Metrics: What and Why?

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OVERVIEW

Key Points

Software Metrics defined

Potential areas where measurement can be effectively applied

Some underlying principles to always keep in mind

In this chapter I would like to define what it is I mean by the term Software Metrics; to discuss in general terms the domain covered by that term according to my definition, and to discuss some of the reasons why an organization may consider the use of Software Metrics.

My introduction to Software Metrics came with a job move from a normal, commercial software engineering environment. The work had also involved some project management. The move required me to change location and I arrived for my first days work fully expecting to be put in charge of a development team only to be offered something completely different. The work they wanted me to get involved in seemed to be dealing with some rather ill defined problems and I also had to figure out how to stop a spreadsheet package beeping at me every few minutes as I made yet another mistake with this new tool.

The first problem we considered concerned the question of change requests that went to make up an enhancement project. Given that the scope of the release might have to be reduced, I had to identify those requests that could most easily be removed from the total package. My most abiding memory of those early days is of other people in the office walking up and asking what I was doing. My answer was invariably "I don't really know but it's good fun." And it was! I was making use of mathematical skills I thought had been consigned to the waste bin, I was meeting people and I had a good level of job satisfaction. What I did not have was a convenient handle by which I could describe my work.

However, we must have been doing something right because the team grew quite quickly from two, myself and my manager, to the grand size of five staff. As we grew we also started to hear of teams in other organizations who were involved in a new fad called Software Metrics. Well not that new nor, perhaps, that much of a fad. The ideas we were hearing about had been around for twenty years or more and some organizations had a significant investment in their use. Even more importantly, a few of these organizations seemed to be getting good returns on that investment. Yet it is true to say that the current widespread interest in Software Metrics only really started in about 1984. Since then, like Topsy, it has 'growed and growed!'

This scenario, of my initial involvement with Software Metrics starting from the organization's almost total naivet regarding the subject to the point where the topic becomes recognized as being important to the business, is not uncommon. It typifies the way in which Software Metrics programs progress and it is worth remembering that a good way to learn about any subject is to start working in that area.

So, our team now had a name that we could associate with our work, "Software Metrics." But what are Software Metrics?

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