meta (version 1.6-1)

trimfill: Generic function for trim-and-fill method

Description

Trim and fill method for estimating and adjusting for the number and outcomes of missing studies in a meta-analysis.

Usage

trimfill(x, ...)

Arguments

x

An object of class meta, or estimated treatment effect in individual studies.

...

Additional arguments as in par.

Value

• An object of class c("metagen", "meta", "trimfill"). The object is a list containing the following components:
• studlab, sm, left, ma.fixed, type
• n.iter.max, level, level.comb,
  As defined above.
• comb.fixed, comb.random
• TE, seTE
  Estimated treatment effect and standard error of individual studies.
• w.fixed, w.random
  Weight of individual studies (in fixed and random effects model).
• TE.fixed, seTE.fixed
  Estimated overall treatment effect and standard error (fixed effect model).
• TE.random, seTE.random
  Estimated overall treatment effect and standard error (random effects model).
• k
  Number of studies combined in meta-analysis.
• Q
  Heterogeneity statistic Q.
• tau
  Square-root of between-study variance (moment estimator of DerSimonian-Laird).
• method
  Pooling method: "Inverse".
• call
  Function call.
• n.iter
  Actual number of iterations to estimate number of missing studies.
• trimfill
  A logical vector indicating studies that have been added by trim and fill method.
• k0
  Number of studies added by trim and fill.

Details

The trim and fill method can be used for estimating and adjusting for the number and outcomes of missing studies in a meta-analysis. The method relies on scrutiny of one side of a funnel plot for asymmetry assumed due to publication bias.

References

Duval S & Tweedie R (2000), A nonparametric "Trim and Fill" method of accounting for publication bias in meta-analysis. Journal of the American Statistical Association, 95, 89--98.

Duval S & Tweedie R (2000), Trim and Fill: A simple funnel-plot-based method of testing and adjusting for publication bias in meta-analysis. Biometrics, 56, 455--463.

See Also

metagen, metabias, trimfill.meta, funnel

Examples

data(Fleiss93)
meta1 <- metabin(event.e, n.e, event.c, n.c,
                 data=Fleiss93, sm="OR")
tf1 <- trimfill(meta1)
summary(tf1)
funnel(tf1, pch=ifelse(tf1$trimfill, 1, 16),
       level=0.95, comb.fixed=TRUE)

trimfill(meta1$TE, meta1$seTE, sm=meta1$sm)