Table 2

Characteristics of oncology studies

Characteristics
(N=296 studies)
Variables
N (%)95% CI
Test subjects
 Animals25 (8.5)
 Humans154 (52.0)
 Both0
 Neither117 (39.5)
Country of journal publication
 USA156 (52.7)
 UK71 (24.0)
 Greece18 (6.1)
 Netherlands11 (3.7)
 Ireland11 (3.7)
 South Korea6 (2.0)
 India4 (1.4)
 Italy2 (0.7)
 Japan2 (0.7)
 Germany1 (0.3)
 Unclear9 (3.0)
 Other5 (1.7)
Country of corresponding author
 USA87 (29.4)
 China52 (17.6)
 Japan19 (6.4)
 Germany16 (5.4)
 South Korea13 (4.4)
 UK12 (4.0)
 Italy10 (3.4)
 Canada7 (2.4)
 France6 (2.0)
 India6 (2.0)
 Unclear8 (2.7)
 Other60 (20.3)
Funding
 University32 (10.8)7.8 to 14.9
 Hospital8 (2.7)1.4 to 5.2
 Public95 (32.1)27.0 to 37.6
 Private/industry6 (2.0)0.9 to 4.4
 Non-profit7 (2.4)1.2 to 4.8
 No statement listed109 (36.8)31.5 to 42.5
 No funding received18 (6.1)3.9 to 9.4
 Mixed21 (7.1)4.7 to 10.6
Conflict of interest statement
 Statement, one or more conflicts of interest57 (19.2)15.2 to 24.1
 Statement, no conflict of interest174 (58.8)53.1 to 64.2
 No conflict of interest statement65 (22.0)17.6 to 27.0
Publication year
 201463 (21.3%)17.0 to 26.3
 201554 (18.2%)14.3 to 23.0
 201649 (16.5%)12.8 to 21.2
 201757 (19.3%)15.2 to 24.1
 201873 (24.7%)20.1 to 29.9
Open access
 Yes, ­ found via open access button139 (47.0)41.4 to 52.7
 Yes, ­ found article via other means26 (8.8)6.1 to 12.6
 No, could only access through paywall131 (44.2)38.7 to 50.0
5-year impact factor
 Median3.445
 First quartile2.2705
 Third quartile5.95
 IQR2.2705–5.95
Most recent impact factor year
 20144 (1.4)
 20150
 20164 (1.4)
 2017271 (91.5)
 20181 (0.3)
 Not found16 (5.4)
Most recent impact factor
 Median3.346
 First quartile2.37375
 Third quartile6.471
 IQR2.37375–6.471
Cited within a systematic review/meta-analysis, N=296*
 No citations257 (86.8%)83.5 to 90.2
 A single citation22 (7.4%)5.0 to 11.0
 1–5 citations17 (5.8%)3.6 to 9.0
 Greater than five citations0
  • *Five studies were explicitly excluded from the systematic reviews/meta-analyses that cited the original article.