Author: James H. Christensen
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In spite of their ability to deliver rapid increments of usable functionality, agile software development processes are frequently characterized as uncontrollable, unrepeatable and incapable of optimization. While sometimes deserved, much of this criticism is the result of misunderstandings and inaccurate preconceptions . In fact, the underlying structure of agile processes makes them more amenable to control, automation and optimization than more traditional software processes. This article will show you how to do it by using a straightforward 3-step procedure that has been successfully applied in the process industries for more than 50 years.
Agile methods focus on incremental delivery and feedback on product value vs. user needs following each increment. Quick action can then be taken on the very next increment to bring the product closer to meeting user needs, even if these have changed from the previous increment.This not only brings the delivered value closer to user needs at each increment, but also reduces risk as the project succeeds through progressive increments, accumulating value at each increment .
In agile methods, increment planning functions as a feedback controller, which compensates both for changing user needs and for deviations in process performance. A key feature of classical feedback control is that the controller generates its control actions based on an "error signal", that is, the difference between the "set point" (user needs) and the controlled variable (delivered functionality).
The velocity estimation step - estimating the quantity of user value delivered per iteration - is an indispensable part of increment planning . This may be based on prior velocity estimates from the same project or previous projects of similar complexity, team size and experience. The team may also use the accuracy of planned vs. delivered value of previous iterations to judge the level of confidence they should have in the velocity estimate.
In order to obtain accurate and consistent velocity estimates and increment plans, the units and methods that are used to estimate user value (the "sizing" step) should be consistent over the course of the project, whether these be "stories", "story points" or "features". It helps to have a brief (no more than one page) written procedure for how to perform this step, based if possible on statistical data from the current and prior projects. This will give consistent process control, even if organizational learning leads to changes in the numbers that are "plugged in" to the procedure.
Once the process is under control, as much of the process as possible should be automated in order to ensure consistent process performance and improved product quality. Quality tool suites, such as CodePro AnalytiX™ from Google , support process automation by providing:
In preparing for process optimization, there are two key questions you should ask about any automated quality tool:
Once process measurements are acquired and retained in a statistical data base, you can apply well-known statistical methods to:
You don't have to to amass large quantities of statistical data in order to begin process improvement using statistical techniques. Of course, you'll need to learn those techniques; fortunately, the necessary information is readily available [5, 6].
Be just as agile and incremental in your process improvement efforts as you are in your product design and development:
The bad news is that you will have to write down some procedures and learn some statistics. The good news is that you will be able to replace endless wrangling and political hassles with quantitative evidence that your process is improving.