Delphi method

Delphi method is a structured communication technique, originally developed as a systematic, interactive forecasting method which relies on a panel of experts. The experts answer questionnaires in two or more rounds. After each round, a facilitator provides an anonymous summary of the experts’ forecasts and the reasons they provide for their judgments. Thus, the experts are encouraged to revise their earlier answers in light of the replies of other members of their panel. It is believed that during this process the range of the answers will decrease and the group will converge towards the "correct" answer. Finally, the process is stopped after a predefined stop criterion (e.g., number of rounds, achievement of consensus, stability of results), and the mean or median scores of the final rounds determine the results.

Delphi has been widely used for business forecasting and has certain advantages over another structured forecasting approach, prediction markets.

History

The method was developed in the early 1950s at the RAND Corporation by Olaf Helmer, Norman Dalkey, and Nicholas Rescher. It was initially intended to forecast the impact of technology on warfare. The Delphi method has been applied in various fields such as policy-making, education, health, and information technology.

Procedure

The Delphi method involves a series of steps:

1. Selection of Experts: The process begins with the selection of a panel of experts, who have knowledge and experience in the area being explored.
2. First Round Questionnaire: The experts are asked to provide their opinions or forecasts in a structured format, usually through questionnaires.
3. Feedback and Anonymity: After the first round, the facilitator provides a summary of the experts' forecasts along with the reasons they have provided. The identities of the experts are kept anonymous to prevent the authority, personality, or reputation of some participants from dominating others.
4. Subsequent Rounds: Based on the feedback, experts are then asked to revise their earlier responses, considering the responses of other members of the panel. This process is repeated for a number of rounds.
5. Aggregation of Responses: The process is concluded once a pre-defined stop criterion is reached. The final decision is based on the aggregation of all the responses, often using statistical methods like the median or mean.

Applications

The Delphi method has been used in various fields, including policy-making, health, education, and information technology forecasting. It is particularly useful in situations where individual judgments need to be aggregated to achieve a consensus decision.

Advantages and Limitations

The main advantages of the Delphi method include its ability to allow a group of individuals to deal with a complex problem. By using an iterative process, with feedback, the method helps in reducing the range of responses and arriving at a more accurate forecast or decision. However, the method has its limitations, including the potential for a loss of depth in understanding if the panel is not well-chosen, and the process can be time-consuming and resource-intensive.

See Also

• Forecasting
• RAND Corporation
• Consensus decision-making
• Expert system