Editorial
Copyright ©2012 Baishideng Publishing Group Co.
World J Gastroenterol. Apr 14, 2012; 18(14): 1555-1564
Published online Apr 14, 2012. doi: 10.3748/wjg.v18.i14.1555
Table 1 Levels of evidence[1]
Levels of evidence
IRandomised clinical trials with P < 0.05, adequate sample size, and appropriate methodology
IIRandomised clinical trials with P < 0.05, inadequate sample size, and/or inappropriate methodology
IIINon-randomised trials with simultaneous controls
IVNon-randomised trials with historical controls
VCase series