Niwot Ridge Resources

A Source of Information for Mission Critical Systems, Management Processes, and Strategies

Software Metrics and Processes

There is whole sub–field of software metrics, and there has been some discussion on New Grange about this. My take on the New Grange threads is they haven't found the real source of software metrics, which is Barry Boehm's COCOMO II models at University of Southern California. A quick search on the web for "software metrics" will turn up many of the answers to the questions being asked on New Grange. There are several approaches to the problem of development metrics that I've found useful. For the non-software types the use of metrics is similar to estimating guidebooks for concrete or steel. "How long will it take to build a building can be estimated by how much steel there is to erect."

COCOMO II, is a current modeling process for non–OO projects (functionally decomposed software rather than object decomposed software). It provides effort estimates based on parameters provided by the user. It has a long history, starting at TRW and Barry's book on the subject of cost estimating.

There is an alternative to the lines of code approach of COCOMO II and that is Function Points. This is a somewhat complex method of counting the functional "points" of the system and determining how many man days the development will take.

The final approach is to use an OO oriented system, that captures how many classes have been identified, the complexity factor of the development (Ala COCOMO II) and compute how long it will take to develop the classes. There is a tool at Steve McConnell's site that computes the time and labor estimates using classes — based on COCOMO II. This works for projects down to a moderate number of classes, but not for "small" projects.

Each of thee methods requires careful planning and is fraught with risk if the parameters are not defined properly. Regression testing of the results is on way to "calibrate" the models. But of course this requires that good metrics were gathered on previous projects. This is the "chicken or the egg" problem.

There is another set of "metrics" which is used for Software Quality Assurance. Any good search engine with "OO Metrics" in the text will find the home sites for these metrics.

Software Processes - UML, XP, and other development processes


In the software process domain there are many good texts and papers. The primary approach is the Software Engineering Institute's Capability Maturity Model. This can be found at the Software Engineering Institute. The debate between heavy weight and light weight processes has been going on for some time. The light weight process include eXterme Programming (XP). This approach has gained more favor recently with the introduction of better text books as well as alternative implementation.

  • The Unified Process Elaboration Phase: best Practices in Implementing the UP, Scott Ambler, R&D Books, 2000. This is the second in a series of Rational Unified Process books. Although the Unified Process would not be considered light weight there are many aspects of RUP that can be applied to light weigh processes and the improvement of organizations using them.

  • eXtreme Programming Explained: Embrace Change, Kent Beck, Addison Wesley, 1999.

  • eXtreme Programming Installed, Ron Jeffries, Ann Anderson and Chet Hendrickson, Addison Wesley, 2000

  • Planning eXtreme Programming, Kent Beck and martin Flower, Addison Wesley, 2000

  • CMM Implementation Guide: Choreographing Software Process Improvement, Kim Caputo, Addison Wesley, 1998. This is a detailed guide book on deploying the SW–CMM. Along with the next book, these texts describe how to plan and deploy a CMM–based process improvement program.

  • Software Process Improvement: Practical Guidelines for Business Success, Sami Zahran, Addison Wesley, 1998.

  • Successful Software Process Improvement, Robert Grady, Prentice Hall. Grady is at HP and leads the process improvement effort there.

  • Software Tech News, is a journal sponsored by the DoD Data & Analysis Center for Software. It contains articles and references to many of the issues in software project management. Subscriptions are free (our tax dollars at work).

 

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