An accessible analytical approach for investigating what happens between the rounds of a Delphi study

The Delphi method is used to investigate consensus amongst a panel of experts using repeated rounds of a questionnaire, often in healthcare settings. However, many Delphi studies do not report any investigation into what happens to the stability of consensus or the convergence of agreement between the rounds in the study, which may be of importance. In this paper an accessible analytical approach is outlined using graphical presentations of means and standard deviations to identify what happens between rounds. For Delphi studies where the scale upon which experts are expressing their opinions can be considered to be interval, the mean will represent the group opinion whilst the standard deviation will represent the level of agreement. An example Delphi study from a healthcare setting is used to illustrate the methodology.