Fig. 2

Design of the 3-stage modified Delphi survey. A total of 179 experts participated over the three stages. A total of 1574 experts from searching the literature were initially contacted and 32 gave responses to an open-ended set of questions (see Table S4). In the Delphi rounds, the response rate to the first round of 132 statements was 46% and the response rate to the second round of 105 statements was 49%