Criteria assessed Score
I. Study design
(maximum score = 11 points)
A. Time Retrospective, 1 point; prospective, 2 point.
B. Randomized sample If stated, 1 point.
C. Control group If present, 1 point.
D. Sample size Subjects ≥ 29, 1 point; power of the study estimated before collection of data, 1 point.
E. Sample gender Both gender included and divided into different groups, 2 points; only male or female, 1 point; both gender included but not divided, 0 point.
F. Objective Clearly formulated, 1 point
G. Selection criteria If they are clearly described and relevant to the topic of the paper, 1 point.
H. Baseline characteristics Similar baseline characteristics, 1 point.
II. Study measurements
(maximum score = 9 points)
A. Segmentation method
(manually or automated) 		If clearly stated, 1 point.
B. Part of airway If the part of airway mentioned consistent with the anatomic definition advocated by
Schwab et al. [44] and Guijarro-Martínez et al. [20], 1 point.
C. Type of airway measurements Volume, 1 point; partial volume, 1 point, Linear, 1 point; smallest cross section, 1 point.
D. Airway measurements adjusted Adjusted to head position (i.e. craniocervical inclination), 1 point; adjusted to a horizontal plane (i.e. FHP), 1 point.
E. Method of acquisition If clearly stated, 1 point.
F. Blinding measurements method If clearly stated and implemented, 1 point.
III. Data analysis
(maximum = 4 points)
A. Statistical analysis If clearly 5stated and appropriate for data, 1 point.
B. Validation of measurements
(error of the method) 		If it’s stated that the method used had been validated in the present paper or validated in early paper, 1 point.
C. Data presentation If P-value stated, 1 point; if any variability measures (standard deviation, confidence interval,
or range) stated, 1 point.