Fig. 1

Flow chart of the Delphi process. The Delphi process begins with the experts board preparing a list of statements based upon an extensive review of the literature. Each Delphi participant is asked to answer the statements according to a Likert scale from 1 to 7. Each Delphi participant receives, in a second round, a questionnaire that includes the same statements and the interquartile range of each question (which represents the range in which 50% of the answers fell) as an index of their colleagues’ responses (from the previous round) and are asked to re-evaluate their initial judgment. Those who answered outside the interquartile range (IQR) in the second round were asked to give a reason for their response. At the end of the second round, the median value and the 25th and 75th percentiles of each statement and IQR were calculated again. The results of the first and second rounds and the motivations of those who had answered outside the interquartile range, were discussed by the expert board at the “verification meeting”