Wideband Delphi is an effort estimation method that can be used for calculating and defining task durations. This method assumes that several groups of experts review and analyze tasks to gain consensus on duration estimates for the tasks. All experts should be experienced and have wide knowledge in the subject matter. They participate in group discussions and brainstorming sessions to review factors influencing task time length, generate possible time estimates, and reach agreement regarding the most probable and accurate estimate.
The greatest advantage of using Wideband Delphi is that this method lets gain a consensus-based estimate of task duration through iterative group discussions and forecast exercises. The method is great for any kind of activity that is supposed to have exact start and end points. The only considerable limitation of the method is that estimation results are deeply dependent on the quality of participants. If experts are not experienced in the subject matter, they cannot give an accurate and unbiased appraisal of task time length.
Here’s an action plan that helps use Wideband Delphi in estimating task duration:
- Select participants for the estimation process
- Form expert groups (no more than 3-4 members per group)
- Provide the groups with a description of the task to be estimated
- Start the estimation process
- Identify factors that have an impact to the task’s duration (e.g. Skills level, Cause variation, Mistakes, Unexpected events, Risks, Cost etc.)
- Be sure every group studies one and the same set of factors
- Receive expert suggestions after the groups finish their discussions
- Review expert suggestions and figure out if one more round of group discussion is necessary
- Receive confirmation about duration appraisals from each individual group
- Share these appraisals between all the groups which must approve or disapprove efficiency of every appraisal
- Iterate group discussions until all experts agree on the most efficient and appropriate duration estimate applicable to the task.