Delphi hackathon – a new approach to develop Core Outcome Sets for blood cancers

Abstract Background The Delphi technique is a well-known and accepted method to reach consensus. However, major challenges in Delphi studies include recruiting suitable participants and avoiding a loss of participants between survey rounds. To mitigate these challenges, we developed a virtual “Delphi hackathon” as a new method to conduct Delphi studies. We have used this new approach to develop Core Outcome Sets (COS) for hematologic malignancies within the scope of the HARMONY PLUS project - as part of the HARMONY Alliance,a public-private European Network established in 2017, which currently includes 53 partners and 76 associated members from 26 countries. Methods In the style of a classic hackathon, known from software development, we organized two virtual meetings where all participants simultaneously participated in two rounds of online Delphi surveys, followed by a third virtual meeting to reach final consensus. Recruitment of participants was done by advertising and providing information via the HARMONY Alliance communication team and patient umbrella organizations. Discussion Big challenges seen in previous Delphi surveys such as difficulties in the recruitment of the various stakeholders to participate in Delphi surveys and their continued support over consecutive Delphi rounds could be favourably addressed by our new Delphi hackathon approach, which showed superior results both with regard to recruitment and continuous support of participants.