Variable Outcome Total (%) Number (%) Period 1 1986-1996 Number (%) Period 2 1997-2003 Number (%) Period 3 2004-2019 p-value
Sign Affirmation 178 (34.8) 60 (50.4) 54 (38.6) 64 (25.4) <0.0001
Negation 101 (19.8) 6 (5) 10 (7.1) 85 (33.7)
Neutral 232 (45.4) 53 (44.5) 76 (54.3) 103 (40.9)
Accuracy Accurate 403 (78.9) 105 (88.2) 112 (80) 186 (73.8) 0.0240
Inaccurate 80 (15.7) 10 (8.4) 19 (13.6) 51 (20.2)
Neither 28 (5.5) 4 (3.4) 9 (6.4) 15 (6)
Attribution Attributed 111 (21.7) 0 (0) 1 (0.7) 110 (43.7) <0.0001
Not attributed 400 (78.3) 119 (100) 139 (99.3) 142 (56.3)
Agenda Setting Agenda setting 205 (40.1) 46 (38.7) 51 (36.4) 108 (42.9) 0.4304
Not agenda setting 306 (59.9) 73 (61.3) 89 (63.6) 144 (57.1)
Article Type Empirical Research 197 (38.5) 50 (42) 66 (47.1) 81 (32.1) 0.0094
Non-Empirical Research 314 (61.5) 69 (58) 74 (52.9) 171 (67.9)
Research Area Neurosciences & Neurology 179 (22.6) 48 (27.1) 55 (24.2) 76 (19.6) 0.0699
Anesthesiology 128 (16.2) 24 (13.6) 44 (19.4) 60 (15.5)
General & Internal Medicine 121 (15.3) 24 (13.6) 36 (15.9) 61 (15.7)
Pharmacology & Pharmacy 56 (7.1) 18 (10.2) 18 (7.9) 20 (5.2)
Psychiatry 39 (4.9) 4 (2.3) 13 (5.7) 22 (5.7)
Health Care Sciences & Services 36 (4.6) 9 (5.1) 10 (4.4) 17 (4.4)
Substance Abuse 21 (2.7) 3 (1.7) 2 (0.9) 16 (4.1)
Psychology 19 (2.4) 6 (3.4) 4 (1.8) 9 (2.3)
Surgery 14 (1.8) 1 (0.6) 4 (1.8) 9 (2.3)
Other 179 (22.6) 40 (22.6) 41 (18.1) 98 (25.3)
Country of Origin USA & Canada 371 (69.7) 75 (62) 86 (58.9) 210 (79.3) <0.0001
Rest of the world 161 (30.3) 46 (38) 60 (41.1) 55 (20.8)