Wideband Delphi

A group estimation technique developed at RAND Corporation in the 1940s and adapted for software by Barry Boehm in the 1980s. In Wideband Delphi, each expert independently estimates a task, the estimates are collected and displayed anonymously, outliers explain their reasoning, and the group re-estimates. This cycle continues until consensus is reached. Planning poker is a streamlined, card-based version of Wideband Delphi: simultaneous reveal prevents anchoring, and discussion after divergent estimates surfaces hidden assumptions. The 'wideband' part refers to including the full team — not just technical leads — so that diverse perspectives are incorporated into estimates.