Skip to main content

Table 2 Numerical characteristics of trials

From: A reinvestigation of recruitment to randomised, controlled, multicenter trials: a review of trials funded by two UK funding agencies

Characteristic Valid n (%) Recruited successfully (%) Mean (SD) Median Minimum to maximum
No. of centers:      
Total 60 (82) 34 (57) 38.6 (47.9) 15.5 2 to 205
2 to 5 16 (27) 9 (56) 3.4 (1.3) 3.5  
6 to 10 9 (15) 5 (56) 7.6 (1.4) 8.0  
11 to 20 7 (12) 4 (57) 14.3 (2.7) 13.0  
21 to 50 11 (18) 6 (55) 33.2 (8.4) 34.0  
51 to 100 9 (15) 4 (44) 68 (12.6) 68.0  
101+ 8 (13) 6 (75) 139.5 (39.5) 119.0  
Target recruitment:      
Total 73 40 (55) 706.3 (1,098.0) 388.0 56 to 8,000
1 to 100 6 (8) 4 (67) 77.8 (14.1) 78.0  
101 to 200 11 (15) 6 (55) 156.8 (30.4) 150.0  
201 to 400 24 (33) 15 (63) 315.9 (56.6) 305.0  
401 to 1,000 22 (30) 10 (46) 637.5 (168.5) 595.0  
1,001+ 10 (14) 5 (50) 2,776 (1,938.7) 2,250.0  
Final recruitment      
Total 73 40 (55) 623.7 (1,117.3) 325.0 44 to 8,164
1 to 100 7 (10) 1 (14) 80.3 (36.8) 58.0  
101 to 200 14 (19) 8 (57) 160.4 (60.1) 151.0  
201 to 400 24 (33) 14 (58) 295.8 (75.6) 284.0  
401 to 1,000 20 (27) 12 (60) 519.2 (313.9) 538.5  
1,001+ 8 (11) 5 (63) 2,476.3 (2,269.6) 2,478.5