What is a Delphi Technique?
The Delphi technique gathers expert judgment anonymously and in rounds: experts answer independently, a facilitator summarizes, everyone sees the anonymous summary and revises, and the group converges. Anonymity is the whole point — it removes the loudest-voice and highest-salary biases from the room.
Exam cue: any scenario about avoiding groupthink, dominant personalities, or one expert swaying the others is pointing at Delphi.
Worked example
Estimating a first-of-its-kind tunnel-boring duration, the PM polls five geotechnical experts separately. Round one spans 9–20 months; after seeing the anonymous reasoning, round two converges on 13–15. The junior engineer's (correct) concern about groundwater carried equal weight to the famous consultant's optimism — which was the point.