1. Are claims of equivalency in digestive diseases trials supported by the evidence? 
Jill M. Tinmouth, Leah S. Steele, George Tomlinson, Richard H. Glazier 
Gastroenterology 
Volume 126, Issue 7, Pages (June 2004)
DOI: /j.gastro

2. Figure 1
Concepts of superiority and equivalency. Various examples of the mean difference (∗) between intervention “a” and intervention “b” (μa − μb) are plotted with 95% confidence intervals (error bars). (A. and B.) In superiority trials, superiority of one intervention over another is proven when the 95% confidence interval around μa − μb excludes zero (B.). (C. and D.) By contrast, in equivalency trials, an equivalency boundary, δ (defined here as ±10%), is selected and equivalency is shown only if the 95% confidence interval around μa − μb falls within ±δ (D.). A comparison of the 95% confidence interval around μa − μb in A. and D. shows how a “failed” superiority trial also fails to show equivalency. Noninferiority, a concept related to equivalency, may be established when the lower 95% confidence limit of μa − μb is greater than −δ (E.).
Gastroenterology  , DOI: ( /j.gastro )

3. Figure 2
Proportion of trials meeting each equivalency criterion and proportion meeting all criteria for the entire study period (1989–2002).
Gastroenterology  , DOI: ( /j.gastro )

4. Figure 3
Proportion of trials meeting different numbers of criteria (from none to all criteria). Solid bars show the proportion that meet exactly a given number of criteria. The line with squares shows the proportion that meet at least a given number of criteria (i.e., a cumulative percentage).
Gastroenterology  , DOI: ( /j.gastro )

5. Figure 4
Proportion of nonsurgical and surgical trials meeting each equivalency criterion and proportion meeting all criteria for the entire study period (1989–2002).
Gastroenterology  , DOI: ( /j.gastro )

6. Figure 5
Proportion of trials meeting each equivalency criterion and proportion meeting all criteria between 1989 and 1995 and between 1996 and 2002.
Gastroenterology  , DOI: ( /j.gastro )

7. Figure 6
Proportion of trials with a research aim of equivalency and without such an aim meeting the remainder of the equivalency criteria (criteria 2–5).
Gastroenterology  , DOI: ( /j.gastro )