Influencing factors of examiner: Examples from certificated orthodontists board examination

The rating result reflects not only the performance of the candidate but some extent of the examiner's preference. Examiner bias could be objective, which means it can't be changed by the examiner like gender, age, race, educational level, or professional experience. No study about examiner bias was performed in the dental education realm, especially in the orthodontic field. Therefore, this study aimed to figure out possible influencing factors in examiners from examples of the Taiwan Board of Orthodontist examination.

The examiner groups comprised 29 males and 21 females selected from the certificated Taiwan Board of Orthodontists. Every examiner would receive a series of lectures about rating standards before the exam. The score data were collected from 2009 to 2019.

As for the univariate regression model of the Taiwan Board of Orthodontist examination, the experienced examiner with a certification of more than 15 years tends to rate more leniently, but female examiners tend to rate harsher. The scores would increase with the examiner's age in both the univariate regression model of self-prepared and assigned cases.

As for the multivariate model of self-prepared exams, the elder and the examiner who work in private practice clinics tend to rate more leniently. As for the multivariate model of the assigned case exam, the score would be only affected by age. However, further studies are necessary to determine the direct relation among these factors.