History of the Delphi method

From a military application to a recognized deliberative tool

At the turn of the 1940s and 1950s, Norman Dalkey and Olaf Helmer laid the foundations for the Delphi method. They were part of a project for the Rand Corporation to define and predict military priorities. The first deployments of the method were aimed at obtaining a convergence of opinions without face-to-face confrontation with those who supported them (Dalkey & Helmer, 1963). It was originally an expert method aimed at fostering dialogue between specialists on a poorly documented and specific question of their field. The idea was to have a “remote” brainstorming session without psychological interference.

Its modalities meet both: the objectives it sets itself — facilitating dialogue within a group or favouring the emergence of a consensus -, and the singularity of the public it mobilizes — experts in a field. In its initial definition, now understood as a classic (Rowe & Wright, 1999), the Delphi method is written and anonymous to free participants from any social pressure that could alter their initial position. However, this position can change and be revised over several iterations. The same panel of experts is therefore consulted on several rounds, informed of the positions taken by the other members of the group (controlled feedback process) and invited to retain or modify its position. This always occurs anonymously, following the principle:

“Decisions are evaluated on their merit, rather than who has proposed the idea” (Skulmoski, Hartman & Krahn, 2007).

The proliferation of publications based on Delphi application is a testament to its success. Once declassified by the US Army (Landeta, 2006 and Gupta & Clarke, 1996), it is used in a wide range of fields: medicine, psychology, educational sciences, management, economics, social sciences, etc.

The widespread use of the method leads to moving from a scientific and technical expertise to a public or “folk” expertise. The panel of participants is no longer necessarily strictly composed of experts in their specialization but can be made up of ordinary people whose competence is contextualised and linked to their involvement and their experience of a problematic situation (Linstone, 1975). Depending on the application, the use of stakeholders and other experiential experts has become widespread. Certain forms of the method (public Delphi) even aim for the involvement of all citizens through the mobilization of mass media (radio, newspapers, internet, etc.) (Glenn, 1994). The objective of the method is then oriented towards the perceptions and representations that these people make of a situation. It may even aim to develop their own folk expertise or ‘usual’ expertise.

The second notable adaptation relates to the very purpose of a Delphi process. The goal of consensus, essential to the original Delphi method, was regularly questioned in terms of validity or quality (Powell, 2002). There is then a shift in emphasis that is no longer so much the achievement of consensus among the participants but rather the attention paid to the quality of the deliberative dimension as it unfolds during the process. This dimension is favoured by one of Delphi’s core principles, the “controlled feedback”. Thus, the participants receive feedback from the main trends that emerged in the previous rounds. They are invited to re-position themselves towards certain issues and to explain why they agree or disagree with the positions of other participants. It is observed that this mode of operation tends to increase consensus in the course of several rounds, but in the current form of the implementation it is not always a primary goal. More attention is being paid to the participatory or deliberative process which tends to become widespread in organizations.