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Copyright ©2014 Baishideng Publishing Group Inc.
World J Gastroenterol. Nov 28, 2014; 20(44): 16529-16534
Published online Nov 28, 2014. doi: 10.3748/wjg.v20.i44.16529
Table 3 Methods of causal inference
Randomized controlled trials
Controlled trials without randomization
Cohort studies
Case-control studies
Ecologic studies
Case reports and case series