The main objective of Delphi studies is to collect expert knowledge for decision-making. In Delphi studies experts’ ideas and opinions are systematically surveyed. The data are gathered through a series of questionnaires interspersed with controlled and anonymous feedback (Häder & Häder 2000). The goal of most Delphi studies is to create a group consensus in future tasks. Although the method originates from the modus operandi of the Greek oracle at Delphi, it is a young research method. The modern Delphi was a spinoff from defense research conducted by the Rand Corporation in the early 1950s at the beginning of the Cold War (Gordon & Helmer 1964). The authors wanted to “obtain the most reliable consensus of opinion of a group of experts” (Linstone & Turoff 1975, 10).
The principle of Delphi studies is based on panel surveys; however, in contrast to such surveys, participants in Delphi studies are confronted with feedback from all participants. Two main assumptions are central: first, the judgment of a group is claimed as superior to judgments of individuals, and, second, the multilevel process of opinion forming is preferred as more valid than the single-level process (Häder 2002). The classic design uses formalized questionnaires that are submitted to experts in the fields analyzed (pencil and paper or online version). The experts are anonymous; the feedback is sent in an averaged form and the questionnaire is repeated at least once. One main aim of the anonymous answering is to bypass the disadvantages of conventional group questionnaires or committee action where social orientation through the identification of communicative or rhetoric leaders has an impact on the result.
As Delphi is a young method its research design can take many forms. Most of these differ in two ways: the number of questionnaires and the number and selection of participating experts. Meta-analysis of Delphi studies shows that a consensus is often established after the second questionnaire. A satisfying result is achieved after the third round at the latest (Häder & Häder 2002). The number of experts varies: huge Delphi studies, as, for example, the 1993 study of the German Federal Ministry of Research and Technology, have more than 3,000 participants. However, many scholars prefer a maximum of 30 participants. Duffield’s (1993) analysis demonstrates that comparable results were produced from two Delphi studies on the same topic but with different numbers of experts (16 and 34). The selection of experts is one of the major problems, as experts need to have not only knowledge but also influence in changing procedures and structures in the relevant field (Duffield 1993). Some authors suggest a standardized pre-questionnaire to determine the level of expertise of the candidates. However, such costly tests are rarely done.
Given that mass communication pertains to a field of rapid technological change, Delphi studies can be seen as having a kind of tradition in this discipline. Krüger, for example, was an early adopter of this method in the field of communication (1975). Nowadays the Delphi technique is applied in the field of new communication technologies (Beck et al. 2000) as well as in the field of public relations (van Ruler et al. 2004; Technology and Communication). Despite the beneficial attributes of Delphi and its application in the field of communication, the method has its critics. The main criticisms are that (1) the outcomes of Delphi studies are mere opinion; (2) the method is not rigorous enough to be part of the serious research methods in the social sciences (Sackman 1974); (3) participants feel pressured to find a consensus; and (4) Delphi tends to simplify the complex tasks of forecasting. To judge the quality of the method, more comparative studies would be needed. These could also make valid statements on different aspects of the design such as the number and structure of the expert groups and/or the usefulness of Delphi as opposed to other foresight techniques like environmental scanning, simulation studies, scenario technique, or trend extrapolation (Häder & Häder 2000).
- Beck, K., Glotz, P., & Vogelsang, G. (2000). Die Zukunft des Internet: Internationale DelphiBefragung zur Entwicklung der Online-Kommunikation [The future of the Internet: An international Delphi study on the development of online communication]. Constance: UVK.
- Duffield, C. (1993). The Delphi technique: A comparison of results obtained using two expert panels. International Journal of Nursing Studies, 30(3), 227–237.
- Gordon, T. J., & Helmer, O. (1964). Report on a long range forecasting study. Rand paper P-2982. Santa Monica, CA: Rand Corporation (September).
- Häder, M. (2002). Delphi-Befragungen [Delphi questionnaires]. Wiesbaden, Germany: Westdeutscher Verlag.
- Häder, M., & Häder, S. (2000). Die Delphi-Methode als Gegenstand methodischer Forschungen [The Delphi method as an object of research]. In M. Häder (ed.), Die Delphi-Technik in den Sozialwissenschaften [The Delphi technique in the social sciences]. Wiesbaden, Germany: Westdeutscher Verlag, pp. 11–31.
- Krüger, U. M. (1975). Die Antizipation und Verbreitung von Innovationen: Entwicklung und Anwendung eines kommunikationsstrategischen Konzeptes unter besonderer Berücksichtigung
- der Delphi-Technik [The anticipation and distribution of innvoations: Development of a strategic communication concept with the help of the Delphi method]. Dissertation, Cologne.
- Linstone, H. A., & Turoff, M. (1975). Introduction. In H. A. Linstone & M. Turoff (eds.), The Delphi method: Techniques and applications. London: Addison Wesley, pp. 1–12.
- Sackman, H. (1974). A Delphi critique. Lexington, MA: Lexington Books.
- van Ruler, B., Vercic, D., Bütschi, G., & Flodin, B. (2004). A first look for parameters of public relations in Europe. Journal of Public Relations Research, 16(1), 1–34.