What Is the Delphi Method?

The Delphi method is a forecasting process framework based on the results of multiple rounds of questionnaires sent to a panel of experts. After each round of questionnaires, the experts are presented with an aggregated summary of the last round, allowing each expert to adjust their answers according to the group response. This process combines the benefits of expert analysis with elements of the wisdom of crowds.

Key Takeaways

  • The Delphi method is a process used to arrive at a group opinion or decision by surveying a panel of experts.
  • Experts respond to several rounds of questionnaires, and the responses are aggregated and shared with the group after each round.
  • The experts can adjust their answers each round, based on how they interpret the "group response" provided to them.
  • The ultimate result is meant to be a true consensus of what the group thinks.

Understanding the Delphi Method

Several rounds of questionnaires are sent out to the group of experts, and the anonymous responses are aggregated and shared with the group after each round. The experts are allowed to adjust their answers in subsequent rounds, based on how they interpret the "group response" that has been provided to them. Since multiple rounds of questions are asked and the panel is told what the group thinks as a whole, the Delphi method seeks to reach the correct response through consensus.

The Delphi method was originally conceived in the 1950s by Olaf Helmer and Norman Dalkey of the Rand Corporation. The name refers to the Oracle of Delphi, a priestess at a temple of Apollo in ancient Greece known for her prophecies. The Delphi method allows experts to work toward a mutual agreement by conducting a circulating series of questionnaires and releasing related feedback to further the discussion with each subsequent round. The experts' responses shift as rounds are completed based on the information brought forth by other experts participating in the analysis.

The Delphi method seeks to aggregate opinions from a diverse set of experts, and it can be done without having to bring everyone together for a physical meeting. Since the responses of the participants are anonymous, individual panelists don't have to worry about repercussions for their opinions. Consensus can be reached over time as opinions are swayed, making the method very effective.

However, while the Delphi method allows for commentary from a diverse group of participants, it does not result in the same sort of interactions as a live discussion. A live discussion can sometimes produce a better example of consensus, as ideas and perceptions are introduced, broken down, and reassessed. Response times with the Delphi method can be long, which slows the rate of discussion. It is also possible that the information received back from the experts will provide no innate value.

The Delphi method is a process of arriving at group consensus by providing experts with rounds of questionnaires, as well as the group response before each subsequent round.

Delphi Method Process

First, the group facilitator selects a group of experts based on the topic being examined. Once all participants are confirmed, each member of the group is sent a questionnaire with instructions to comment on each topic based on their personal opinion, experience, or previous research.

The questionnaires are returned to the facilitator who groups the comments and prepares copies of the information. A copy of the compiled comments is sent to each participant, along with the opportunity to comment further. At the end of each comment session, all questionnaires are returned to the facilitator who decides if another round is necessary or if the results are ready for publishing.

The questionnaire rounds can be repeated as many times as necessary to achieve a general sense of consensus.

What Are the Advantages of the Delphi Method?

The Delphi method seeks to aggregate opinions from a diverse set of experts, and it can be done without having to bring everyone together for a physical meeting. Since the responses of the participants are anonymous, individual panelists don't have to worry about repercussions for their opinions. Consensus can be reached over time as opinions are swayed, making the method very effective.

What Are the Disadvantages of the Delphi Method?

The Delphi method does not result in the same sort of interactions as a live discussion. A live discussion can sometimes produce a better example of consensus, as ideas and perceptions are introduced, broken down, and reassessed. Response times with the Delphi method can be long, which slows the rate of discussion. It is also possible that the information received back from the experts will provide no innate value.

How Is the Delphi Method Conducted?

The group facilitator selects a group of experts based on the topic being examined and sends them a questionnaire with instructions to comment on each topic based on their personal opinion, experience, or previous research.


The facilitator groups the comments from the returned questionnaires and sends copies to each participant, along with the opportunity to comment further. At the end of this session, the questionnaires are returned to the facilitator who decides if another round is necessary or if the results are ready for publishing.


This process can be repeated multiple times until a general sense of consensus is reached.