Chapter 12. A Software Metrics Primer[13]
Note
My friend Nicole is a quality manager at a large company recognized for its software process improvement and measurement success. Once I heard her say, "Our latest code inspection only found two major defects but we expected to find five, so we’re trying to figure out what’s going on." Few organizations have enough insight into their software engineering process to make such statements. Nicole’s organization spent years establishing effective processes, measuring critical aspects of its work, and using those measurements on well-managed projects that develop high-quality products.
Software measurement is a challenging but essential component of a healthy and highly capable software engineering culture. This chapter describes some basic software measurement principles and suggests some metrics that can help you understand and improve the way your organization and its projects operate (Jones 1996; Wiegers 1996). Project initiation is a good time to choose the appropriate measures that will help you assess project performance and product quality. Plan your measurement activities carefully because they can take significant initial effort to implement and the payoff will come over time.
Software projects are notorious for running over schedule and budget and having quality problems to boot. Software measurement lets you quantify your schedule and budget performance, work effort, product size, product quality, and project status. If you don’t measure your current performance and use the data to improve your future work estimates, those estimates will just be guesses. Because today’s current data becomes tomorrow’s historical data, it’s never too late to begin recording key information about your project.
You can’t track project status meaningfully unless you know the actual effort and time spent on each task compared to your plans. You can’t sensibly decide whether your product is stable enough to ship unless you’re tracking the rates at which your team is finding and fixing defects. You can’t assess how well your new development processes are working without some measure of your current performance and a baseline to compare against. Metrics help you better control your software projects and better understand how your organization works.
[13] This chapter was originally published in Software Development, 1999, 7(7): 39–42. It is reprinted here, with modifications, with permission of CMP Media Inc.