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Table 4 Univariate predictors of high impact factor (> 5)

From: Journal impact factor, trial effect size, and methodological quality appear scantly related: a systematic review and meta-analysis

Potential predictorsOdds ratio (95% CI)p value
Effect size (relative risk) 0.66
 0–0.51.367 (0.423, 4.415) 
 0.5–1Ref 
 > 10.774 (0.399, 1.501) 
Statistically significant2.667 (0.962, 7.390)0.06
Mortality is primary outcome1.671 (0.554, 5.038)0.36
Multicenter2.880 (1.183, 7.011)0.02
Medical domain 0.07
 Medicine6.872 (1.180, 40.027) 
 Obstetrics3.325 (0.264, 41.731) 
 Pediatrics1.727 (0.3096, 9.636) 
 SurgeryRef 
Any industry funding2.595 (1.102, 6.111)0.03
Peer review funding1.275 (0.489, 3.324)0.62
Random sequence1.352 (0.641, 2.852)0.43
Allocation concealment, clearly adequate (A) or not (BCD)1.188 (0.616, 2.288)0.61
Double-blind1.564 (0.544, 4.503)0.41
Analysis as randomized 0.09
 Unclear0.427 (0.158, 1.155) 
 As treated0.320 (0.131, 0.783) 
 As randomizedRef 
Sample size (every 10 increase)1.014 (1.002, 1.026)0.02
Country 0.84
 Canada/USA2.651 (0.257, 27.376) 
 Europe2.108 (0.213, 20.864) 
 AsiaRef 
 Other2.000 (0.183, 21.861) 
  1. CI confidence interval