Delphi technique draws on “group intelligence” and relies on the fact that although no one person may be able to provide reliable estimates confidently, the middle range of estimates drawn from a population of stakeholders is frequently a realistic predictor for numeric results. Delphi taps into undocumented history, often yielding very realistic estimates and forecasts. The collaborative process also builds motivation, ownership, buy-in, and teamwork.
To begin the process, clearly state the question requiring a numeric answer, such as:
Activity duration estimates
Quantitative risk analysis of impact or probability
Forecasts for return on investment analysis
Gather five or more people who possess ...