Surveys (incl. expert and delphi surveys)


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Delphi Survey

Short Version

In a Delphi survey experts are questioned in a structured group discussion to learn about and explore future trends in order to receive estimates on the likelihood of developments in the future, particularly in regard to technology driven processes (e.g. development of the market for electro cars). Questions in Delphi surveys will oftentimes address a time span of ten and more years. In impact assessment processes Delphi surveys may be useful when developing policy options and policy measures.

Definition & Objectives

A Delphi survey is a structured group interaction process that is directed in "rounds" of opinion collection and feedback. Opinion collection is achieved by conducting a series of surveys using questionnaires. The result of each survey will be presented to the group and the questionnaire used in the next round is built upon the result of the previous round.

The Delphi survey has two main objectives:

1. To obtain estimates for important parameters in the evaluation framework where no or insufficient published data was currently available.

2. To consult individuals with a working knowledge of current policy on various aspects of the surveillance and research programme.


Delphi involves an iterative survey of experts. Delphis may focus on forecasting technological or social developments, helping to identify and prioritise policy goals or determining expert opinion about some aspect of affairs that cannot be measured directly by conventional statistical means. A dialectical process, Delphi was designed to provide the benefits of a pooling and exchange of opinions so that respondents can learn from each others’ views, without the sort of undue influence likely in conventional face−to−face settings (which are typically dominated by the people who talk the loudest or have most prestige). Each participant completes a questionnaire and then is given feedback on the whole set of responses. With this information in hand, (s)he then fills in the questionnaire again, this time providing explanations for any views they hold that were significantly divergent from the viewpoints of the other participants. The explanations serve as useful intelligence for others. The idea is that the entire group can thus weigh dissenting views that are based on privileged or rare information. While traditionally conducted via mail, other variations of Delphi can be online or face−to−face (see: Dick (2000), ICIS, Steyaert and Lisoir (2005))


Dick, B. (2000), Delphi face to face [On line]. Glenn, J. (Ed.), Futures Research Methodology. Version 1.0. AC/UNU The Millennium Project. Available at

ICIS Building Blocks for Participation in Integrated Assessment: A review of participatory methods.

Steyaert, S and Lisoir, H (2005). Participatory methods toolkit – A practitioner’s manual, King Baudouin Foundation and Flemish Institute for Science and Technology Assessment


Based on Simon, Karl−Heinz, Alexa Matovelle, Ângela Guimarães Pereira and Tiago Pedrosa: Delphi Survey
This introduction to the method was developed as part of the FP6 project SustainabilityA-Test. coordinated by IVM (Insitute for Environmental Studies).


Expert Survey


Wikipedia Survey methodology.