Introduction to the Delphi technique

What is the Delphi technique?

The Delphi technique is a widely used inquiry method that cross-cuts many disciplines and applications.

The technique, in the words of Listone and Turoff "may be characterized as a method for structuring a group communication process so that the process is effective in allowing a group of individuals, as a whole, to deal with a complex problem".

The technique usually involves several rounds of communication without face-to-face interaction, thus often having a degree of anonymity.

Historically, it was developed at RAND Corporation (an American think tank first formed to offer research and analysis to the U.S. military) in the early 1950s in a project funded by the US Air Force. Concretely, it was first used as a way to establish reliable consensus of opinion among a group of experts about how Soviet military planners might target the US industrial system in an attack and how many atomic bombs would be needed to have a specified level of impact on US military capability.

To which situations does the Delphi technique apply?

Every area of human activity can be a candidate for using the Delphi technique. Thus, the nature of the domain or problem is not the criteria to select the use of the Delphi technique.

The following are criteria that could be used to determine the appropriateness of Delphi for a given situation (they are neither necessary nor sufficient conditions, however):

• The problem can not be solved by precise analytical techniques, but a solution can be approached by the subjective judgments of a group of individuals.
• The individuals in the group do not constitute a regular working team, but they have to contribute with their different backgrounds to the examination of a broad or complex problem.
• The number of individuals in the group is too large to have an effective face-to-face interaction.
• Time, location or other restrictions make infeasible or impractical frequent group meetings.
• There is a need for anonymity in the contrast of opinions for some political or practical reason.
• There is a need to avoid an effect of leadership in opinion, or a bias towards group consensus, as often happens in face-to-face meetings.

The Delphi technique can be used as the sole communication procedure, or it can be used to complement other kinds of group communication activities.

Which are the general steps of the Delphi technique?

There is not a unique sequence of steps or procedure for the Delphi technique, since different situations may benefit from different approaches.

However, there are some basic elements that are common to all the applications of the Delphi technique. The following is a list of them:

• The participants have feedback on their contributions, and an opportunity to revise them.
• There is an assessment of the group view on the problem.
• There is a degree of anonymity for the individual contributions.

The "conventional form of Delphi" usually works as follows:

• The (small, sometimes a single person) monitor team designs a questionnaire and sends it to the members of the group.
• The members of the group (individually) return the responses to the monitor team.
• The monitor team summarizes the results, designs a new questionnaire based on them (including a synthesis of the responses of the group), and sends it again to the group.
• The members of the group return the responses to the monitor team, possibly revising their initial opinions.
• Based on the revised responses and the degree of consensus, the monitor team decides to go again to the third step or to finally conclude the process.

The number of "rounds" in a Delphi process depends on the nature of the problem. Usually, there is an initial phase of contributions of information on the problem, a second phase of discussion of diverging views of the group members, and a final phase of evaluation.

Where can I find information about the Delphi technique?

The original reference Delphi book was "The Delphi Method: Techniques and Applications" by Harold Linstone and Murray Turoff, Addison Wesley, 1975.

Now the original reference book edited by Linstone and Turoff has a freely available version that can be found here: http://www.is.njit.edu/pubs/delphibook/ .

The Wikipedia also provides a good introduction and some references. The article can be found at http://en.wikipedia.org/wiki/Delphi_method