METHODS: The study design followed the Delphi technique. A select panel of 35 international experts gave their opinion via a three-round digital Delphi survey as to whether the instrument as a whole, and its items, adequately measure the construct of embouchure. Criteria for consensus and whether items should go through to the next Delphi round were pre-determined. Data were independently analyzed by two researchers. The CREDES guidelines were used for conducting and reporting of the study.
RESULTS: Consensus was reached over 64% and 73% of the closed questions in the first and third rounds, respectively. A second round was necessary to resolve intra- and inter-expert contradicting information. Finally, 5 items were added to the instrument, 3 items were removed, and 23 items were adjusted. Consensus was reached in 63 items (98%). The final multi-item assessment instrument consists of 4 domains and 64 items.
CONCLUSIONS: Content validity of most aspects of the \"CODE of embouchure\" instrument was established.