Table 2

Adjusted ORs of author rank relative to middle rank, according to author contributions, among 1101 authors of 108 research articles with five or more authors published in 2015 in the Annals of Internal Medicine (conditional logistic regression analysis)

ContributionAuthor rank
First (vs middle)Second (vs middle)Next to last (vs middle)Last (vs middle)
OR (95% CI)p ValueOR (95% CI)p ValueOR (95% CI)p ValueOR (95% CI)p Value
Conception and design of the study6.9 (2.6 to 17.9)<0.0011.5 (0.9 to 2.6)0.151.6 (0.9 to 2.7)0.086.4 (2.8 to 14.7)<0.001
Analysis and interpretation of the data10.2 (1.1 to 91.5)0.0383.5 (1.6 to 7.8)0.0021.6 (0.9 to 2.8)0.153.4 (1.1 to 9.9)0.027
Drafting of the article73.5 (9.2 to 584.4)<0.0012.3 (1.3 to 4.0)0.0041.0 (0.6 to 1.7)0.961.3 (0.7 to 2.6)0.43
Critical revision of the article for important intellectual content0.4 (0.2 to 1.0)0.0421.4 (0.7 to 2.8)0.300.6 (0.3 to 1.0)0.05413.8 (2.8 to 68.4)0.001
Final approval of the article1.3 (0.3 to 6.2)0.740.6 (0.3 to 1.4)0.271.7 (0.8 to 3.8)0.172.5 (0.5 to 13.5)0.28
Provision of study materials or patients6.5 (2.2 to 19.2)0.0011.2 (0.6 to 2.6)0.591.2 (0.6 to 2.4)0.521.4 (0.6 to 3.2)0.38
Statistical expertise1.5 (0.7 to 3.1)0.271.3 (0.7 to 2.3)0.371.0 (0.5 to 1.8)0.941.1 (0.5 to 2.2)0.89
Obtaining of funding2.6 (1.1 to 6.5)0.0351.5 (0.7 to 3.4)0.301.7 (0.8 to 3.6)0.1318.0 (6.5 to 49.8)<0.001
Administrative, technical, or logistical support1.0 (0.5 to 1.9)0.950.7 (0.4 to 1.4)0.321.8 (1.1 to 3.1)0.0232.6 (1.4 to 5.1)0.004
Collection and assembly of data1.3 (0.6 to 3.0)0.502.0 (1.1 to 3.4)0.0180.7 (0.4 to 1.1)0.120.7 (0.3 to 1.4)0.26