Background: Various evaluation methods for acne severity have been used without standardization. Objectives: To investigate physician-based evaluation methods in clinical studies of acne vulgaris and to determine differences according to time, region, and study design. Methods: PubMed was searched for articles on acne published from January 2000 to June 2019 in 5 dermatology journals. Clinical studies with acne vulgaris evaluation methods were selected. Results: A total of 186 articles were selected. Articles from 2010 to 2019 used Investigator Global Assessment (IGA; odds ratio [OR], 5.808; 95% CI, 1.894-17.811) more often and the Leeds technique (OR, 0.282; 95% CI, 0.098-0.812) less often compared with articles from 2000 to 2009. Controlled experimental studies preferred lesion counting (OR, 238.637; 95% CI, 46.795-1216.954), IGA (OR, 9.177; 95% CI, 3.053-27.586), and Leeds Revised Acne Grading System (LRAGS; OR, 10.844; 95% CI, 3.050-38.559) compared with observational studies. North American studies applied lesion counting (OR, 4.573; 95% CI, 1.173-17.836) and IGA (OR, 11.330; 95% CI, 3.487-36.818) more often and LRAGS (OR, 0.171; 95% CI, 0.039-0.758) less often compared with European studies. Conclusion: Acne evaluation methods varied by time, region, and study design.