Duval and Tweedie’s Trim and Fill method
•Uses an iterative procedure to remove most extreme small studies from positive side of funnel plot, re-computing effect size at each iteration until funnel plot is symmetric about new effect size
•Yield an unbiased estimate of effect size
•Trimming also reduces variance of effects, yielding a too narrow C.I.
•Therefore algorithm then adds original studies back into analysis, and imputes a mirror image for each.
•This fill has no impact on point estimate but serves to correct the variance
the black dots are studies added after the method...
PSM / COMMUNITY MEDICINE by Dr Abhishek Jaiswal is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Based on a work at learnpsm@blogspot.com.
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