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The Dorset House Quarterly Interviews

Lawrence H. Putnam and Ware Myers
Authors of Five Core Metrics: The Intelligence Behind Successful Software Management

ISBN: 978-0-932633-55-2  
©2003  328 pages   softcover  
$43.95 (plus shipping)


DHQ: What are the "five core metrics" featured in your new book? When in the development process do you take those measurements?

Putnam: The five core metrics are size, schedule time, effort (cost), defects, and process productivity. You use them from the start of and then throughout the life of the development process, whenever necessary and appropriate.

Myers: In the first two phases of the Unified Process, Inception and Elaboration, one of the purposes is to figure out sufficiently what is to be done, in order to attach a size estimate to the project. So, thinking about what is to be done (especially in terms of size) goes all the way back to the beginning.

DHQ: Who on the development team is responsible for recording metrics? Does it require additional staff?

Putnam: The project manager is responsible overall. He or she usually has a quality assurance team as part of the development team. This is often a very good place to put the metrics collection and analysis function. It can be done as a part-time effort. It usually does not require a full-time dedicated person. Tools are useful for recording and processing the metrics data. The tools can be homegrown using spreadsheets. Also, there are excellent commercial tools that have been specially developed for this purpose. Such tools aid in collecting the metrics data and also provide analytical capabilities to interpret the data and tell the story the metrics are designed to convey.

DHQ: How often do you record the metrics?

Putnam: Monthly or weekly during development, so you have a good time history of what went on during the project.

DHQ: How often and when do you do analysis work with the metrics?

Putnam: Do analysis at the start of the project, using historic data and estimates of the key parameters for the new project. This is related to the estimate for the new project. Update this estimate whenever the scope or other key factors of the project change. Use the monthly or weekly metrics data to do comparison analysis as soon as the project is underway. By the time the project is roughly 25 percent complete in schedule, you can compare actuals against the plan and make an adaptive update forecast if actuals are deviating significantly from plan. At the end of the project, capture all the key information relating to the size, schedule, effort, and defects. Use this to determine the process productivity achieved. Store this in your metrics repository to use on new projects coming along.

Ware: One addition that I would make to what Larry said is something about the psychology of data collection. Management should make it clear that this data is being collected for metric purposes, not for personnel use. People are willing to collect data honestly for estimating and control purposes, but if they suspect it is to have something to do with personnel appraising, they begin to fudge the data and consequently to distort the data for metric purposes.

DHQ: What's new about relating metrics to the Unified Process, and why isn't it enough to follow the process without metrics?

Putnam: Metrics can be a part of any development methodology and should be. The originators of the Unified Process did not make metrics a part of their original creation. However, the company they are affiliated with, Rational, has been integrating metrics with a number of its products and is beginning to infuse its thinking with metrics concepts. Metrics ideas are important to the management of development because they allow resource requirements for development to be integrated into the planning and control process that is at the heart of management. This permits you to put the right number of staff on the project at the right time; it permits the prediction of when defects will occur and how many, so defect elimination is timely; it allows you to project ahead to determine when the defect discovery rate will be low enough that the product can be released for use by the end user. These metrics functions are important to the planning and control of any development process. There is a significant void in development when metrics are not used.

DHQ: Won't keeping track of metrics make it more difficult to follow a formal software development process?

Putnam: Keeping track of metrics during development is not an onerous task. It can be handled part-time by project support people (usually in quality assurance). The volume of data collected is very modest when focused on the five core metrics we discuss in our book. There are good commercial tools available that collect data, help with analysis, and plan and control the development process, so the time and effort spent servicing the metrics work is very modest and not costly.

Myers: It is perfectly true that collecting metric data takes a little time and making use of it takes a little more time. But it is customary on a planet of limited resources—limited daytime, limited lifespans, and so on—to try to get work done within some limits. In fact, we have a name for it: competition. And those who don't come close to competition-set limits are removed from business (and even government). In software development, the name for this set of activities is metrics. To the extent that software development is an economic activity, not a weekend pastime, it has to base itself on metrics, and most organizations do use some kind of metrics. The issue, really, is whether the metrics are good or "seat of the pants." Part of making them good is the realization that they are tied into process, models, and tools.

DHQ: Don't metrics bog-down the speed and creativity of software development?

Putnam: No. Actually, they speed it up because there are fewer false starts and fewer rework cycles. They can be handled as a by-product of the development process. Moreover, they provide valuable insights into what is happening on the project while it is under way, and they afford an opportunity to make timely changes to the project by providing near-real-time observation of problems that may ultimately cause cost and schedule overruns.

Myers: I think you could even put the issue in the reverse form. Lack of metrics, and of the process, models, tools, and so on that are concomitants of metrics, causes projects to fail or to overrun arbitrarily set cost and schedule limits.

DHQ: If my group hasn't kept track of metrics in the past, what can I do as an individual—and what must my group do—to start using metrics?

Putnam: Any innovation has to start sometime. Look for the opportunity and push to get it started on your project. Point out the benefits of early visibility of problems and of having better plans for avoiding the problems and bottlenecks that happen without the use of metrics. Work on the culture change that may be necessary to convince team members that metrics will help them avoid death marches, which are common in the absence of good metrics use.

Myers: In addition to Larry's observation that an individual can encourage the use of metrics, you need to convey to management on a broader scale, as we do in the book, the advantages that metrics, when integrated into process, models, and tools, can bring to the organization. For an indication of the meager interest that management has displayed in the subject, note that the Harvard Business Review seldom deals with the management of software development. Yet it is not only costly in its own right, but failure to develop effective software impinges on every other area of business.

DHQ: Compare this book with your previous collaborations—what's new?

Putnam: This book is less about the mechanics of estimating and measurement and much more about how metrics fit into the development process and yield real benefits to the development team and the paying customer. It is a more integrated view of metrics as an essential part of the development process.

Myers: I would add to Larry's observations that the present book spends more time on the first two phases, Inception and Elaboration, and the fourth phase, Transition, than our earlier books did. Our first book, Measures for Excellence, started at the point where some experienced people sat down to estimate the size of a system that had already been outlined. How the system got to the point of being sized, we did not deal with very much. Similarly, we largely stopped at the end of the Construction phase, saying little about the problems of getting a system into operation in the field.
     Secondly, the earlier books largely assumed that there would be a software process of some sort and that a given organization would be able to repeat it. Without repetition capability, of course, an estimate is futile. Organizations tend to go on doing what they are already doing, of course. In this book, we have been much more explicit about process. It has now been more firmly established that there is process, and that the process can be vastly improved by consciously taken steps. We add that Putnam's methods can measure this improvement, which supports the motivation to improve the process.
     Finally, in Part IV of the book, we go beyond the level of the individual project and consider department- or company-level problems that are amenable to effective software management.

DHQ: What projects are you working on now, together or individually?

Putnam: I'm working on updates to our Web page, articles for the Web page, new copy for the latest version of our SLIM tools (V 6.0) and a pitch at the 2nd International Conference on Process Improvement in mid-November. In addition, I'm trying to focus on business matters, to get back on an upswing after three years of depression in the economy. Things look better now, and we need to exploit that.
     I have been interested for a long time in whether or not our estimating approach and key algorithm (software equation) would work in other domains. I think we are quite confident that they will. I want to pursue this idea, get some data, test it more thoroughly than we have already, and perhaps turn it into a usable tool.

Myers: However, I may be in the process of arriving at an idea—something to the effect that software development is a good deal bigger than just writing code. In Five Core Metrics, we developed the relationship between metrics and process, plus models, plus tools. In another book, we might extend all that to the field of negotiation. At the front end, prior to the inception phase, we might extend software development back into the reengineering area, that is, we might overhaul existing practices first.
     Looked at in this way, it becomes evident that this whole has to exist in an economic framework measured and controlled by some kind of metrics. This whole is an obvious concern of top management. And while some in that field are meeting the challenge, many are not.
     Well, I don't know if I know enough to cover this broad scope, but it won't do any harm to let the bigger idea germinate for a while. In effect, I am in the early stages of thinking about the next book, but I am not yet ready to spill the beans, because most of the beans are not in the pot yet.

DHQ: Thanks, Larry and Ware!

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