Reflections on the application of the Delphi method: lessons from a case in public transport research

The paper outlines the author’s experience employing the Delphi method, using as an example a particular application of the Delphi in the field of public transport research. Attention is given to aspects such as the choice of method, selection of experts, design of questionnaires, interaction between survey coordinator and participants, and also the analysis of experts’ responses. Some of the challenges encountered during the survey, the way they were dealt with, and risk mitigation strategies used by the Delphi coordinator are highlighted too. The primary objective of this paper is to offer insights that can support other researchers or practitioners preparing to apply the Delphi methodology. Furthermore, the article contributes to the methodological debate by reflecting on the introduction of novel practices that can help overcome some typical pitfalls of the Delphi: a dedicated blog supporting the survey, safety-net questions, and a constant-sum type question.