In more than half the studies included in our review, at least one
physical meeting of panel participants was held. Having a physical
meeting contradicts one of the basic rules of the Delphi procedure,
which is avoidance of situations that might allow one of the panel
members to dominate the consensus process. Conversely, absence
of a meeting may deprive the Delphi procedure of benefits related
to face-to-face exchange of information, such as clarification of
reasons for disagreements [45]. For example, other formal
consensus methods such as the nominal group technique [46]
and the Rand UCLA Appropriateness Method [23] use a highly
structured meeting to gather information from relevant experts.