Navigating the Delphi jungle: Evaluating the Delphi method in the health and social sciences

The Delphi method is a recognised tool for addressing complex issues that are subject to knowledge constraints, for it allows the viewpoints of experts from various domains to be systematically incorporated into a decision-making process. However, the objectives and methodological configurations of individual Delphi processes can vary considerably. As a result, numerous methodological variants have evolved, including the Group Delphi, Policy Delphi, and Real-Time Delphi. While the adaptability of the method allows researchers to tailor procedures to divergent research contexts, this impairs standardisation while also limiting comparability between studies. Accordingly, it is responsible at least in part for many challenges that arise in the areas of expert selection, questionnaire design, and methodological implementation. These considerations highlight the need to shed greater light on the method’s promises and pitfalls, so as to strengthen the quality and credibility of the Delphi method as a practical tool. This study surveys experts affiliated with DeWiss, a German-language Delphi network, to examine their experience with using the method. Specifically, we assess the real-world implementation of the Delphi method from the perspective of the quality indicators. Our study aims to contribute to ongoing epistemological and methodological debate on the topic of quality assurance in Delphi research. A closely related objective is to provide inexperienced practitioners with insights that can enhance the quality and rigour of their research.