Fig. 2.

a Numbers of participants (separated in known participants and anonymous participants) over the course of the Delphi process (Delphi rounds). b Experience (in years) of participants over the course of the Delphi rounds. c Representation of fields of expertise over the course of the Delphi rounds. Multiple selections of fields of expertise per participant were possible. Rounds marked with a “(C)” (rounds 3 and 5) were rounds that focused on the challenge prioritization and characterization