Brainstorming has potential disadvantages. When meeting attendees are not familiar with risk assessment technique, their suggestions may not be particularly helpful. If there is a high level manager in the meeting room, individuals may feel a certain chill about uttering their thoughts too forthrightly. Furthermore, the meeting method can miss taking note of important sources of risk. The effort will have been vitiated if, later during project execution, potential risks emerge that were not identified back at the time of the brainstorming session.
The Delphi method is not traditional in practical life, but it has its uses and advantages for focusing the consciousness of key project personnel not only upon identifying sources of risk but also their own responsibility, both individual and collective, to be prepared to manage whatever risks emerge during project execution. The name "Delphi" is derived from the Oracle of Delphi. The authors of the method were not happy with this name, because it implies "something oracular, something smacking a little of the occult." The Delphi method is based on the assumption that group judgments are more valid than individual judgments.
The Delphi method was developed at the beginning of the Cold War to forecast the impact of technology on warfare (1999). In 1944, General Henry H. Arnold ordered the creation of the report for the U. S. Army Air Corps on the future technological capabilities that might be used by the military.
Different approaches were tried, but the shortcomings of traditional forecasting methods, such as theoretical approach, quantitative models, or trend extrapolation, in areas where precise scientific laws have not been established yet, quickly became apparent. To combat these shortcomings, the Delphi method was developed by Project RAND during the 1950s and 1960s (1959) by Olaf Helmer, Norman Dalkey, and Nicholas Rescher (1998). It has been used ever since, together with various modifications and reformulations such as the Imen-Delphi procedure.
This method is based on the idea that the opinion of a group is better than the opinion of one person. As during the Vietnam War when the US Chiefs of Staff repeatedly resorted to this approach, the Delphi method was used by asking experts to give their opinion on the probability, frequency, and intensity of possible enemy attacks. Other experts could anonymously give feedback. This process was repeated several times until a consensus emerged.
In the same way, every expert in this type of project should be queried separately about the expected potential risk of the project. Nowadays, this method is easy due to e-mail, video conferences, and other methods of communication that appear every day. The process begins with the facilitator using a questionnaire to solicit risk ideas about the project. The responses from the participants are then categorized and clarified by the facilitator. Several such rounds of one-on-one may be repeated until a consensus emerges around the final list of project risks. The largest benefit from this method is its relatively low cost, but it makes greater demands on whoever fills the facilitator role.