Content-validity.

Six external experts rated the importance of each proposed morphometric measure (5-point Likert scale, endpoints: 1 = disagree, 5 = Strongly agree) within the three domians:1) description of dentofacial growth deviation (descriptive content), 2) Treatment planning, 3) Long-term changes validity. An average validity score ≥ 3.5 was considered of high content-validity. Additionally, the general importance is illustrated by the general strength of outcome measure (VAS 0–100 mm, endpoints: 0 = not important, 100 = extremely important) and rank of importance (1–21, 1 = most important, 21 = least important).