Saturday, June 07, 2008

Project Estimation : Wide Band Delphi

Software development is inherently unpredictable in nature. Consequently, preparing a project estimate is not the easiest of task to do. It’s much evident from the fact that not more than 20% of software developments around the globe are always out of schedule. It’s true that getting 100% on-time delivery of your work products is a not the easiest of the job, as many volatile factors govern the development process. But, for sure, we can reduce the affects. People often predict the development time and forget the golden rule that, it is project “Estimate” and NOT project “Prediction”. Being part of SEPG group of my organization, this is my journey in studying different Estimation Methods available.

First of all, I am looking at WideBand Delphi. WBD, unlike other methods like COCOMO or Function Point Analysis, doesn’t depend on historical datas.

A team of experts would join together in an estimation sessions and individually estimate the task list of the project. These individual estimations are summarized by the Estimation co-coordinator, commonly in a tabular format and presented back to the expert panel. In the cases (task list) where there is variance (non-convergence) more than a predefined value, the panel would reassess the tasks and if possible break it down further into sub tasks and once again go through the whole process.

As you can see, WBD is a simple method, which underlines the fact that estimation is not rocket science. Its strength lies in fact the estimator has strong domain knowledge and that they are working independently would ensure process is unbiased.

But WBD could be made better, and that’s what we would be looking forward in the next entry. Wide Band Delphi variations like Confidence interval and Neinburg approximation would further enhance this method and making it more analytical.