Establishing test-retest reliability and the smallest detectable change of FACE-Q Aesthetic Module scales

BACKGROUND: The test-retest (TRT) reliability of FACE-Q Aesthetic scales is yet to be assessed. The aim of this study was to establish the TRT reliability of 17 FACE-Q Aesthetic scales and determine the smallest detectable change (SDC) that can be identified using these scales. METHODS: Data were collected from an online international sample platform (Prolific). Participants ≥20 years old, who had been to a dermatologist or plastic surgeon for a facial aesthetic treatment within the past 12 months were asked to provide demographic and clinical information and complete an online REDcap survey consisting of 17 FACE-Q Aesthetic scales. Participants were asked if they would be willing to complete the survey again in 7 days. Only the participants who reported no important change in the scale construct and completed the retest within 14 days were included. RESULTS: A total of 342 unique participants completed the TRT survey. The mean age of the sample was 36.6 (±11.5) years, and 82.4% were female. With outlier data removed, all FACE-Q scales demonstrated an intraclass correlation coefficient >0.70 indicating "good" TRT reliability. The standard error of measurement for the included scales ranged from 3.37 to 11.87, corresponding to a range of SDC_group from 0.95 to 3.23 and SDC_ind from 9.34 to 32.91. CONCLUSION: All included FACE-Q scales demonstrated sufficient TRT reliability and stability overall after the outlier data were removed. Moreover, the authors calculated the values for the SDC for these scales.