What is Delphi?

#Delphi is an iterative, anonymous, structured, group-based method for expert elicitation and stakeholder engagement that helps explore the existence of consensus in a group. Delphi involves a series of questionnaires that participants answer based on their professional expertise and personal experience. Sometimes, they are asked to review a summary of existing research evidence before providing their answers. Once participants answer the first round of questions and explain their responses, they see how their own answers compare to those of others and can revise their responses if needed. This process continues until stability or consensus is reached or a certain number of rounds is completed. In general, statistically-determined expert consensus is considered to be more reliable than the opinion of a single expert, because it helps harness the wisdom of knowledgeable individuals while mitigating negative effects of dominant personalities and groupthink, both of which are common in group settings.

RAND researchers started working on the #DelphiMethod in the late 1940s. Their goal was to obtain a reliable expert consensus, which could be used as a form of empirical evidence when no other forms of evidence exist, to make more reliable forecasts of future political developments, such as predicting the impact of technology on warfare. With time, the Delphi method became a powerful tool in a wide range of disciplines, including social sciences, medicine, and policy sciences, that looked for alternatives to regression-based models to forecast future and deal with uncertainty.

The Delphi method was not a methodological hit from day one; it took the method several decades to become widely used. Its early developers were a group of RAND researchers working on projects funded by the United States Air Force. Launches of two journals in late 1960s—Futures and Technological Forecasting and Social Change—helped popularize the Delphi method among social scientists and technologists who applied it to a range of complex social problems. However, it is the medical field that became the biggest user of the Delphi method starting in the 1980s when health care quality, including appropriateness, became a hot topic. Starting from the 2000s, roughly two-thirds of all Delphi articles were published in medical journals. Check out this article if you want to learn more about disciplinary trends in the use of the Delphi method.

Besides being the biggest Delphi users, health researchers are also responsible for introducing multiple modifications to the method itself. Among them is the RAND/UCLA Appropriateness Method (RAM), which is often referred to as “modified Delphi” or simply as “expert panel.” Although there is no consensus on what modified Delphi really means, RAM introduced the following 5 key changes to the traditional Delphi method:

1)?pre-specified and limited the number of rounds

2) added an in-person discussion round between two rounds of questions, which required an experienced discussion moderator

3) limited the number of participants to 9-18 experts with different types of expertise

4)?promoted the use of 9-point Likert scales with a validated measure of consensus

5)?required a review of evidence to be shared with experts before the first round of questions.

Want to learn more about the Delphi method? Check out my other Delphi articles on:

1) How to design Delphi studies. This article talks about the types of projects that could benefit from the Delphi method, discusses key Delphi project design characteristics, and explains how to choose panelists.

2) How to ask good Delphi questions. This article provides guidance on how to develop Delphi items, questions, and response scales.

3) How to administer Delphi panels. This article explains how to conduct virtual Delphi panels.

4) How to minimize participant attrition in Delphi panels. This article presents strategies for increasing participant engagement and retention in virtual Delphi panels.

5) How to analyze and report Delphi results. In this article. This article explains how to analyze and present quantitative and qualitative data collected in Delphi studies.

6) How to account for Delphi limitations. This article describes 4 strategies for addressing Delphi limitations as you design your Delphi panels.

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