Likert scale vs visual analog scale for assessing facial pleasantness

Abstract

•Facial pleasantness was assessed with Likert and visual analog scales. •Oral surgeons, orthodontists, and laypeople evaluated sets of photographs. •Results were similar regardless of the scale used. •Most evaluators preferred the Likert scale because of its simplicity. Introduction This study aimed to compare the 2 most commonly used methods for assessing facial pleasantness, the Likert scale and the visual analog scale (VAS). Methods For assessing facial pleasantness, an album was assembled containing the front and profile view facial photographs of 10 patients (5 females, 5 males) who sought orthodontic treatment representing each of the different sagittal and vertical facial discrepancies (straight profile, convex profile, concave profile, long faces, and short faces). The facial pleasantness of the patients was judged by 3 groups of 90 evaluators (47 females and 43 males): 30 orthodontists (mean age, 32.41 years), 30 oral maxillofacial surgeons (mean age, 36.83 years), and 30 laypeople (mean age, 36.83 years). The evaluators judged the facial pleasantness using VAS and a 5-point Likert scale. At the end of the evaluation, the evaluators completed a questionnaire about their preferred scale. Analysis of variance and Tukey and Kruskal-Wallis tests were used to compare the data from VAS and Likert scale, respectively. The Spearman correlation coefficient was used to estimate the correlation between the 2 scales. Fisher transformation and z-statistic were used to estimate the correlation among the evaluator groups. In all tests, a 5% statistical significance level was adopted. Results Both scales presented similar answers; only VAS values for the scores of pleasant and very pleasant according to the Likert scale could not be distinct. Most evaluators preferred the Likert scale as they found it easier to convey their opinion than VAS. Conclusions Although both scales can be used to assess facial pleasantness, the Likert scale seems more appropriate as the evaluators preferred it because of its simplicity. This study aimed to compare the 2 most commonly used methods for assessing facial pleasantness, the Likert scale and the visual analog scale (VAS). For assessing facial pleasantness, an album was assembled containing the front and profile view facial photographs of 10 patients (5 females, 5 males) who sought orthodontic treatment representing each of the different sagittal and vertical facial discrepancies (straight profile, convex profile, concave profile, long faces, and short faces). The facial pleasantness of the patients was judged by 3 groups of 90 evaluators (47 females and 43 males): 30 orthodontists (mean age, 32.41 years), 30 oral maxillofacial surgeons (mean age, 36.83 years), and 30 laypeople (mean age, 36.83 years). The evaluators judged the facial pleasantness using VAS and a 5-point Likert scale. At the end of the evaluation, the evaluators completed a questionnaire about their preferred scale. Analysis of variance and Tukey and Kruskal-Wallis tests were used to compare the data from VAS and Likert scale, respectively. The Spearman correlation coefficient was used to estimate the correlation between the 2 scales. Fisher transformation and z-statistic were used to estimate the correlation among the evaluator groups. In all tests, a 5% statistical significance level was adopted. Both scales presented similar answers; only VAS values for the scores of pleasant and very pleasant according to the Likert scale could not be distinct. Most evaluators preferred the Likert scale as they found it easier to convey their opinion than VAS. Although both scales can be used to assess facial pleasantness, the Likert scale seems more appropriate as the evaluators preferred it because of its simplicity.