Delphi method
The Delphi method, or Delphi technique, is a structured communication technique, or method, originally developed as a systematic, interactive forecasting method that relies on a panel of experts. Delphi has been widely used for business forecasting and has certain advantages over another structured forecasting approach, prediction markets.
Delphi can also be used to help reach expert consensus and develop professional guidelines. It is used for such purposes in many health-related fields, including clinical medicine, public health, and research.
Delphi is based on the principle that forecasts from a structured group of individuals are more accurate than those from unstructured groups. The experts answer questionnaires in two or more rounds. After each round, a facilitator, or change agent, provides an anonymised summary of the experts' forecasts from the previous round as well as the reasons they provided for their judgments. Thus, 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 stopping criterion, and the mean or median scores of the final rounds determine the results.
Special attention has to be paid to the formulation of the Delphi theses and the definition and selection of the experts in order to avoid methodological weaknesses that severely threaten the validity and reliability of the results.
Ensuring that the participants have requisite expertise and that more domineering participants do not overwhelm weaker-willed participants, as the first group tends to be less inclined to change their minds and the second group is more motivated to fit in, can be a barrier to reaching true consensus.
History
The name Delphi derives from the Oracle of Delphi, although the authors of the method were unhappy with the oracular connotation of the name, "smacking a little of the occult". The Delphi method assumes 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. 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, quickly became apparent in areas where precise scientific laws have not been established yet. To combat these shortcomings, the Delphi method was developed at Project RAND by Olaf Helmer, Norman Dalkey, and Nicholas Rescher. It has been used ever since, together with various modifications and reformulations, such as the Imen-Delphi procedure.
Experts were asked 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 2021, a cross-disciplinary study by Beiderbeck et al. focused on new directions and advancements of the Delphi method, including Real-time Delphi formats. The authors provide a methodological toolbox for designing Delphi surveys including among others sentiment analyses of the field of psychology.
Key characteristics
The following key characteristics of the Delphi method help the participants to focus on the issues at hand and separate Delphi from other methodologies: in this technique a panel of experts is drawn from both inside and outside the organisation. The panel consists of experts having knowledge of the area requiring decision making. Each expert is asked to make anonymous predictions.Anonymity of the participants
Usually all participants remain anonymous. Their identity is not revealed, even after the completion of the final report. This prevents the authority, personality, or reputation of some participants from dominating others in the process. Arguably, it also frees participants from their personal biases, minimizes the "bandwagon effect" or "halo effect", allows free expression of opinions, encourages open critique, and facilitates admission of errors when revising earlier judgments.Structuring of information flow
The initial contributions from the experts are collected in the form of answers to questionnaires and their comments to these answers. The panel director controls the interactions among the participants by processing the information and filtering out irrelevant content. This avoids the negative effects of face-to-face panel discussions and solves the usual problems of group dynamics.Regular feedback
The Delphi method allows participants to comment on the responses of others, the progress of the panel as a whole, and to revise their own forecasts and opinions in real time.Role of the facilitator
The person coordinating the Delphi method is usually known as a facilitator or Leader, and facilitates the responses of their panel of experts, who are selected for a reason, usually that they hold knowledge on an opinion or view. The facilitator sends out questionnaires, surveys etc. and if the panel of experts accept, they follow instructions and present their views. Responses are collected and analyzed, then common and conflicting viewpoints are identified. If consensus is not reached, the process continues through thesis and antithesis, to gradually work towards synthesis, and building consensus.During the past decades, facilitators have used many different measures and thresholds to measure the degree of consensus or dissent. A comprehensive literature review and summary is compiled in an article by von der Gracht.
Applications
Use in forecasting
First applications of the Delphi method were in the field of science and technology forecasting. The objective of the method was to combine expert opinions on likelihood and expected development time, of the particular technology, in a single indicator. One of the first such reports, prepared in 1964 by Gordon and Helmer, assessed the direction of long-term trends in science and technology development, covering such topics as scientific breakthroughs, population control, automation, space progress, war prevention and weapon systems. Other forecasts of technology were dealing with vehicle-highway systems, industrial robots, intelligent internet, broadband connections, and technology in education.Later the Delphi method was applied in other places, especially those related to public policy issues, such as economic trends, health and education. It was also applied successfully and with high accuracy in business forecasting. For example, in one case reported by Basu and Schroeder, the Delphi method predicted the sales of a new product during the first two years with inaccuracy of 3–4% compared with actual sales. Quantitative methods produced errors of 10–15%, and traditional unstructured forecast methods had errors of about 20%.
The Delphi method has also been used as a tool to implement multi-stakeholder approaches for participative policy-making in developing countries. The governments of Latin America and the Caribbean have successfully used the Delphi method as an open-ended public-private sector approach to identify the most urgent challenges for their regional ICT-for-development eLAC Action Plans. As a result, governments have widely acknowledged the value of collective intelligence from civil society, academic and private sector participants of the Delphi, especially in a field of rapid change, such as technology policies.
Use in patent participation identification
In the early 1980s Jackie Awerman of Jackie Awerman Associates, Inc. designed a modified Delphi method for identifying the roles of various contributors to the creation of a patent-eligible product. The results were then used by patent attorneys to determine bonus distribution percentage to the general satisfaction of all team members.Use in policy-making
From the 1970s, the use of the Delphi technique in public policy-making introduces a number of methodological innovations. In particular:- the need to examine several types of items leads to introducing different evaluation scales which are not used in the standard Delphi. These often include desirability, feasibility and probability, which the analysts can use to outline different scenarios: the desired scenario, the potential scenario and the expected scenario ;
- the complexity of issues posed in public policy-making tends to increase weighting of panelists' arguments, such as soliciting pros and cons for each item along with new items for panel consideration;
- likewise, methods measuring panel evaluations tend to increase sophistication such as multi-dimensional scaling.
- the iteration structure used in the paper Delphis, which is divided into three or more discrete rounds, can be replaced by a process of continuous interaction, enabling panelists to change their evaluations at any time;
- the statistical group response can be updated in real-time, and shown whenever a panelist provides a new evaluation.
- the involvement of a large number of participants,
- the use of two or more panels representing different groups, which the administrator can give tasks reflecting their diverse roles and expertise, and make them to interact within ad hoc communication structures. For example, the policy community members may interact as part of the main conference panel, while they receive inputs from a virtual community involved in a side conference. These web-based variable communication structures, which he calls Hyperdelphi, are designed to make Delphi conferences "more fluid and adapted to the hypertextual and interactive nature of digital communication".