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Figure 7 | BMC Medical Research Methodology

Figure 7

From: A system for rating the stability and strength of medical evidence

Figure 7

Example of a Qualitative Robustness Test. Cumulative meta-analytic-test of the qualitative of seven randomized trials that compared pharmacotherapeutic treatment for bulimia to placebo and reported mean purging frequency. We performed a cumulative meta-analysis in which the study with the largest weight was entered first (the topmost horizontal segment in the plot), and then the study with the next largest weight was entered (the second one from the top), etc. Each horizontal segment in the plot is a 95% confidence interval around a random-effects summary Hedges' d, a standardized mean difference. (The point estimates are not shown to clarify that the analysis focuses only on confidence intervals, not point estimates). In each of the last five analyses, the effect was statistically significant in the same direction. This met our a priori definition of qualitative robustness, which was that the qualitative conclusion must have remained the same after each of the last three or more studies were added.

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