The Voting Scheme Determines the Winner. Considering Possible Options for Designing a Delphi Study

The Delphi technique is an important tool for structuring a group communication process among key stakeholders to inform the development of an intervention. However, when designing a Delphi study the scarcity of information on different voting schemes to analyse key stakeholders’ responses became evident, despite the fact that selecting the voting scheme a priori is paramount, since the selected method can influence the outcome. To fill that gap in literature, this article introduces key concepts derived from social choice theory to inform Delphi design. This includes optimising collective decisions by gaining deeper understandings of key stakeholders’ preferences, reducing avoidable unhappiness and minimising possibilities of insincere voting strategies. Four voting schemes (majority, approval, Borda, range) are presented and their implications are discussed. Since the purpose of each Delphi study is unique, we aim to increase awareness of the differential utility of voting schemes and encourage researchers to make an informed choice.