Table 2 General characteristics of the study sample
Characteristic | Number | Percent |
|---|---|---|
Total number of articles | 39,305 | 100.0 |
Journal (top-10) | ||
The Lancet | 3593 | 9.1 |
Journal of Clinical Oncology | 3343 | 8.5 |
The New England Journal of Medicine | 3275 | 8.3 |
The BMJ | 2516 | 6.4 |
Circulation | 2331 | 5.9 |
JACC Journal of the American College of Cardiology | 2133 | 5.4 |
JAMA | 1904 | 4.8 |
Diabetes Care | 1885 | 4.8 |
Journal of Allergy and Clinical Immunology | 1345 | 3.4 |
European Heart Journal | 1315 | 3.3 |
Year of publication | ||
Before 1980 | 2004 | 5.1 |
1980–1989 | 4040 | 10.3 |
1990–1999 | 9626 | 24.5 |
2000–2009 | 12,574 | 32.0 |
2010–2017 | 11,061 | 28.1 |
Journal impact factor (2016) | ||
10.0–15.0 | 12,150 | 30.9 |
15.1–20.0 | 10,388 | 26.4 |
20.1–25.0 | 7174 | 18.3 |
25.1–30.0 | 238 | 0.6 |
>30.0 | 9355 | 23.8 |
Main subject categorya | ||
Medicine, General & Internal | 13,688 | 30.7 |
Cardiac & Cardiovascular Systems | 5828 | 13.1 |
Oncology | 5760 | 12.9 |
Gastroenterology & Hepatology | 3023 | 6.8 |
Psychiatry | 2380 | 5.3 |
Number of citations | ||
0–50 | 15,449 | 39.3 |
51–100 | 8714 | 22.2 |
101–500 | 13,056 | 33.2 |
501–1000 | 1445 | 3.7 |
>1000 | 641 | 1.6 |
Number of authors | ||
1 | 1064 | 2.7 |
2–3 | 3405 | 8.7 |
4–6 | 10,340 | 26.3 |
7–10 | 11,142 | 28.3 |
>10 | 13,354 | 34.0 |
Country of first author (top-10) | ||
United States | 14,508 | 36.9 |
United Kingdom | 4924 | 12.5 |
The Netherlands | 1874 | 4.8 |
Germany | 1862 | 4.7 |
Canada | 1847 | 4.7 |
France | 1732 | 4.4 |
Italy | 1720 | 4.4 |
Australia | 999 | 2.5 |
Sweden | 755 | 1.9 |
Denmark | 660 | 1.7 |
Source of funding | ||
Reported | 16,485 | 41.9 |
None/not reported | 22,820 | 58.1 |