Table 1. Characteristics of substantial overlap manuscripts compared to manuscripts without substantial overlap (n = 100).

	No substantial overlap (n = 81)	Substantial overlap papers (n = 19)	p-value
English journal impact factor mean (SD**)	2.64 (1.99)	1.67 (0.88)	0.009
English journal article influence factor mean (SD)	0.85 (0.84)	0.47 (0.35)	0.06
Mean number of institutions (SD)	2.3 (1.5)	1.5 (0.7)	0.02
Published before 2004 (95% CI)	16.0% (8.8–23.2)	0 (NA)	0.12
More than one institution (95% CI)	65.4% (55.7–74.4)	34.6% (25.7–44.3)	0.04
Institutions outside China* (95% CI)	21.0% (13.0–29.0)	0 (NA)	0.04
Funding outside China* (95% CI)	10.3% (4.1–15.8)	0 (NA)	0.33
First author from Hong Kong or Taiwan (95% CI)	19.8% (12.2–27.8)	5.3% (0.7–9.3)	0.18

*China here includes Hong Kong and Taiwan.

**Standard deviation.