["We explored how readers interpret authors' roles based on authorship order and corresponding author.", "We conducted a cross-sectional survey of all 291 Surgical and Medical Chairpersons across North America. We developed hypothetical study and authorship bylines with five authors varying the corresponding author as first or last author. Respondents reported their perceptions about the authors' roles in the study and the most prestigious authorship position. We used multinomial regression to explore the results.", "One hundred sixty-five chairpersons (response rate: 57%) completed our survey. When the first author was designated as corresponding author, most of the respondents assumed that this author had taken the lead in study design (55.3%) and analysis and interpretation of data (51.2%). When the last author (fifth) was designated as corresponding, perceptions of the first author's role in study concept and design (odds ratio [OR]\xa0=\xa00.25, 95% confidence interval [CI]: 0.15, 0.41) and analysis and interpretation of results (OR\xa0=\xa00.22, 95% CI: 0.13, 0.38) decreased significantly. Overall prestige of the last author position increased significantly when designated as corresponding author (OR\xa0=\xa04.0, 95% CI: 2.4, 6.4)."] Are perceptions of authors ' contributions influenced by both byline order and designation of corresponding author?