WIDEBAND DELPHI APPROACH

The Delphi approach or Wideband Delphi technique attempts to gather the opinions of a group of experts with the aim of producing an accurate unbiased estimate. It is a structured technique of expert judgement and is essentially a form based technique involving a multistep procedure:

1. Experts are issued the specification and estimation form by the co-ordinator.
2. A group meeting is held to discuss the product and estimation issues.
3. Experts produce an independent estimate.
4. Estimates are returned indicating the median estimate and the expert’s personal estimate.
5. Another group meeting is held to discuss results.
6. Experts prepare a revised independent estimate.
7. Steps 3-6 are repeated until a consensus is reached by the panel of experts.

Assessment of the Wideband Delphi Approach

The method is very good at removing the politics from an estimate, as the experts do not communicate about their particular estimate and the method filters out extreme opinions making the estimate unbiased, which is often at fault in many other estimation techniques. The group discussion is particularly advantageous as it ensures that any estimation issues are not overlooked. The father of all software cost estimation publications produced by [BOEHM 82] indicates the effectiveness of the wideband delphi technique and stresses the importance of the group meeting.

 

This page was last updated 12/3/97 Dan. Snell, Bournemouth University, Copyright. 1997