Delphi method
A method that asks a group of experts through questionnaires in several rounds and, between rounds, gives them back a summary of what the group answered so they can revise their opinion.
What it’s for
Helps gather the judgment of many experts on something uncertain, such as a possible future, without the loudest voice weighing most.
Key elements
Several rounds
Each round builds on what came out of the previous one.
The group's answer, summarized
Each expert sees where the group stands and can change or defend their answer.
Agreement is sought, not forced
The disagreements that remain are also a result.
How it’s done
Choose the group of experts and the question.
Each expert answers in writing, in each round.
Return the summary and repeat until the answers settle.
Applications in design
When to use it
When you need expert judgment on something that can't be measured yet, such as trends or future scenarios.
Avoid
Choosing only experts who think alike; the result will look like an agreement that doesn't exist.
Don’t fall for it
Agreement among experts is not proof: it's still an opinion.
Connections
Builds on
Authors and works
- 1963
Norman Dalkey and Olaf Helmer
They published an experiment with the method, which aimed to reach a reliable group opinion through successive questionnaires and controlled feedback of the group's answers.
Sources
Original sources
- Dalkey, N., & Helmer, O. (1963). An experimental application of the Delphi method to the use of experts. Management Science, 9(3), 458–467. View source: Dalkey, N., & Helmer, O. (1963)
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