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)

Contribution	Author rank
	First (vs middle)		Second (vs middle)		Next to last (vs middle)		Last (vs middle)
	OR (95% CI)	p Value	OR (95% CI)	p Value	OR (95% CI)	p Value	OR (95% CI)	p Value
Conception and design of the study	6.9 (2.6 to 17.9)	<0.001	1.5 (0.9 to 2.6)	0.15	1.6 (0.9 to 2.7)	0.08	6.4 (2.8 to 14.7)	<0.001
Analysis and interpretation of the data	10.2 (1.1 to 91.5)	0.038	3.5 (1.6 to 7.8)	0.002	1.6 (0.9 to 2.8)	0.15	3.4 (1.1 to 9.9)	0.027
Drafting of the article	73.5 (9.2 to 584.4)	<0.001	2.3 (1.3 to 4.0)	0.004	1.0 (0.6 to 1.7)	0.96	1.3 (0.7 to 2.6)	0.43
Critical revision of the article for important intellectual content	0.4 (0.2 to 1.0)	0.042	1.4 (0.7 to 2.8)	0.30	0.6 (0.3 to 1.0)	0.054	13.8 (2.8 to 68.4)	0.001
Final approval of the article	1.3 (0.3 to 6.2)	0.74	0.6 (0.3 to 1.4)	0.27	1.7 (0.8 to 3.8)	0.17	2.5 (0.5 to 13.5)	0.28
Provision of study materials or patients	6.5 (2.2 to 19.2)	0.001	1.2 (0.6 to 2.6)	0.59	1.2 (0.6 to 2.4)	0.52	1.4 (0.6 to 3.2)	0.38
Statistical expertise	1.5 (0.7 to 3.1)	0.27	1.3 (0.7 to 2.3)	0.37	1.0 (0.5 to 1.8)	0.94	1.1 (0.5 to 2.2)	0.89
Obtaining of funding	2.6 (1.1 to 6.5)	0.035	1.5 (0.7 to 3.4)	0.30	1.7 (0.8 to 3.6)	0.13	18.0 (6.5 to 49.8)	<0.001
Administrative, technical, or logistical support	1.0 (0.5 to 1.9)	0.95	0.7 (0.4 to 1.4)	0.32	1.8 (1.1 to 3.1)	0.023	2.6 (1.4 to 5.1)	0.004
Collection and assembly of data	1.3 (0.6 to 3.0)	0.50	2.0 (1.1 to 3.4)	0.018	0.7 (0.4 to 1.1)	0.12	0.7 (0.3 to 1.4)	0.26