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What is the trim and fill method?
The idea of the trim-and-fill method is to first trim the studies that cause a funnel plot’s asymmetry so that the overall effect estimate produced by the remaining studies can be considered minimally impacted by publication bias, and then to fill imputed missing studies in the funnel plot based on the bias-corrected …
What is Duval and Tweedie trim and fill method?
A Nonparametric “Trim and Fill” Method of. Accounting for Publication Bias in Meta-Analysis. Sue DUVAL and Richard TWEEDIE. Meta-analysis collects and synthesizes results from individual studies to estimate an overall effect size.
What is funnel plot in meta-analysis?
Funnel plots are a visual tool for investigating publication and other bias in meta-analysis. They are simple scatterplots of the treatment effects esti- mated from individual studies (horizontal axis) against a measure of study size (vertical axis).
How is fail safe N calculated?
In order to calculate a Failsafe-N, first described by Rosenthal (1979), a test of combined significance is conducted. The failsafe number is the number of missing studies averaging a z-value of zero that should be added to make the combined effect size statistically insignificant (see Figure 26 for an example).
What is a good fail safe N?
The minimum number of undetected negative studies that would be needed to change the conclusions of a meta-analysis. A small fail-safe N suggests that the conclusion of the meta-analysis may be susceptible to publication bias.
What is file drawer effect?
Publication bias is sometimes called the file-drawer effect, or file-drawer problem. Positive-results bias, a type of publication bias, occurs when authors are more likely to submit, or editors are more likely to accept, positive results than negative or inconclusive results.
How would you interpret p value using Egger’s regression test?
Egger’s test for a regression intercept gave a p-value of 0.028, indicating possible publication bias. The funnel plot for Figure 4B shows no evidence of publication bias. Begg and Mazumdar’s test for rank correlation gave a p-value of 1.000, indicating no publication bias.
How is trim and fill used in meta-analysis?
Trim and fill: A simple funnel-plot-based method of testing and adjusting for publication bias in meta-analysis We study recently developed nonparametric methods for estimating the number of missing studies that might exist in a meta-analysis and the effect that these studies might have had on its outcome.
How to use a funnel plot in a meta-analysis?
We study recently developed nonparametric methods for estimating the number of missing studies that might exist in a meta-analysis and the effect that these studies might have had on its outcome. These are simple rank-based data augmentation techniques, which formalize the use of funnel plots.
When do you use trim and fill method?
Description. The trim and fill method is a nonparametric (rank-based) data augmentation technique proposed by Duval and Tweedie (2000a, 2000b; see also Duval, 2005). The method can be used to estimate the number of studies missing from a meta-analysis due to the suppression of the most extreme results on one side of the funnel plot.
Who is the creator of trim and fill?
The trim and fill method is a nonparametric (rank-based) data augmentation technique proposed by Duval and Tweedie (2000a, 2000b; see also Duval, 2005).