Wideband Delphi
Wideband Delphi is an expert-based estimation technique in which multiple participants independently estimate effort, discuss differences, and refine estimates through several rounds until consensus is reached.
“An expert-based test estimation technique that aims at making an accurate estimation using the collective wisdom of the team members.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Wideband Delphi?
The technique improves estimation accuracy by combining expert judgment with structured collaboration and iterative review.
Expert driven: Relies on knowledgeable participants.
Iterative estimation: Estimates are refined over multiple rounds.
Consensus building: Discussion helps reduce estimation bias.
Real World Example
A regulated product team is preparing a release where Wideband delphi appears in reviews, test design conversations, or defect triage rather than as an isolated glossary word.
The risk is that the team treats Wideband delphi as interchangeable with nearby ISTQB terms. That makes test scope blurry and can lead to weak evidence for the release decision.
The tester anchors the discussion in the official definition, asks where the concept appears in the product, and designs examples that show the difference between Wideband delphi and similar ideas.
The page becomes useful in practice because Wideband delphi is connected to a specific testing decision, not memorized as a detached definition.
Practice Questions
Question 1
Which statement BEST describes Wideband delphi in the context of ISTQB terminology?
Question 2
A tester needs to explain Wideband delphi to a non‑technical stakeholder. Which approach is MOST appropriate?
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