1. Validity of randomized clinical trials in gastroenterology from 1964–2000 
Lise L. Kjaergard, Sarah L. Frederiksen, Christian Gluud 
Gastroenterology 
Volume 122, Issue 4, Pages (April 2002)
DOI: /gast
Copyright © 2002 American Gastroenterological Association Terms and Conditions

2. Fig. 1
Mean proportion of trials (standard error of the mean) with adequate allocation concealment from 1964 to 2000 in 9-year intervals and from 1991 to 2000.
Gastroenterology  , DOI: ( /gast )
Copyright © 2002 American Gastroenterological Association Terms and Conditions

3. Fig. 2
Mean number of patients per intervention arm (standard error of the mean) in randomized trials from 1964 to 2000 in 9-year intervals.
Gastroenterology  , DOI: ( /gast )
Copyright © 2002 American Gastroenterological Association Terms and Conditions