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Trim-and-Fill Method


When publication bias is suspected in a systematic review, investigators may attempt to estimate the true intervention effect by removing, or trimming, small positive studies that do not have a negative study counterpart and then calculating a supposed true effect from the resulting symmetric funnel plot. The investigators then replace the positive studies they have removed and add hypothetical studies that mirror these positive studies to create a symmetric funnel plot that retains the new pooled effect estimate. This method allows the calculation of an adjusted confidence interval and an estimate of the number of missing trials.

Categories: Bias Prevention