Adjustment of Assessors' First Impressions Differs by Student Ethnicity.

Introduction: Ethnic minority medical students often receive lower grades than their majority counterparts, especially in workplace-based assessments. To unravel this phenomenon of "differential attainment", we explore assessor bias focusing on how first impressions of students from ethnic minority groups may be adjusted differently compared to majority students when their performance changes. Methods: In an online experiment with an incomplete block design we created near-identical videos showcasing varying performances of medical students during history-taking. Eighty-one physicians were randomly assigned to watch four different videos each, two with ascending performances (poor start, good ending) and two with descending performances (good start, poor ending), featuring one ethnic minority actress (Turkish or Moroccan origin) and one ethnic majority actress (Dutch origin) as students. We evaluated ethnicity-related differences in first impression ratings (after 60 seconds), final ratings (after 5 minutes), and rating changes. Results: No significant differences in first impression ratings were found between ethnic groups. Ethnic minority students received higher final ratings than ethnic majority students for ascending performances, but only when rated by residents and not specialists. Finally, rating changes between first impressions and final ratings were larger for ethnic minority than ethnic majority students, for both ascending and descending performances. Discussion: Our results do not show evidence of assessor bias in first impressions being an explanation for ethnicity-related differential attainment. However, our finding that rating changes were larger for minority than majority students could indicate that they are generally more scrutinized by assessors, which may affect them positively, but also negatively.