meta (version 3.0-1)

metacum: Cumulative meta-analysis

Description

Performs a cumulative meta-analysis.

Usage

metacum(x, pooled, sortvar)

Arguments

x

An object of class meta.

pooled

A character string indicating whether a fixed effect or random effects model is used for pooling. Either missing (see Details), "fixed", or "random", can be abbreviated.

sortvar

An optional vector used to sort the individual studies (must be of same length as x$TE).

Value

• An object of class c("metacum", "meta") with corresponding print, plot function. The object is a list containing the following components:
• TE, seTE
  Estimated treatment effect and standard error of pooled estimate in cumulative meta-analyses.
• lower, upper
  Lower and upper confidence interval limits.
• studlab
  Study label describing addition of studies.
• p.value
  P-value for test of overall effect.
• w
  Sum of weights from fixed effect or random effects model.
• I2
  Heterogeneity statistic I2.
• tau
  Square-root of between-study variance.
• df.hakn
  Degrees of freedom for test of treatment effect for Hartung-Knapp method (only if hakn=TRUE).
• sm
  Summary measure.
• method
  Method used for pooling.
• k
  Number of studies combined in meta-analysis.
• pooled
  As defined above.
• comb.fixed
  A logical indicating whether analysis is based on fixed effect model.
• comb.random
  A logical indicating whether analysis is based on random effects model.
• TE.fixed, seTE.fixed
  Value is NA.
• TE.random, seTE.random
  Value is NA.
• Q
  Value is NA.
• level.comb
  The level used to calculate confidence intervals for pooled estimates.
• hakn
  A logical indicating whether the method by Hartung and Knapp is used to adjust test statistics and confidence intervals.
• method.tau
  A character string indicating which method is used to estimate the between-study variance $\tau^2$.
• tau.preset
  Prespecified value for between-study variance $\tau^2$.
• TE.tau
  Overall treatment effect used to estimate the between-study variance $\tau^2$.
• n.harmonic.mean
  Harmonic mean of number of observations (for backtransformation of Freeman-Tukey Double arcsine transformation).
• version
  Version of R package meta used to create object.

Details

A cumulative meta-analysis is performed. Studies are included sequentially as defined by sortvar.

Information from object x is utilised if argument pooled is missing. A fixed effect model is assumed (pooled="fixed") if argument x$comb.fixed is TRUE; a random effects model is assumed (pooled="random") if argument x$comb.random is TRUE and x$comb.fixed is FALSE.

References

Cooper H & Hedges LV (1994), The Handbook of Research Synthesis. Newbury Park, CA: Russell Sage Foundation.

See Also

metabin, metacont, print.meta

Examples

data(Fleiss93)
meta1 <- metabin(event.e, n.e, event.c, n.c,
                 data=Fleiss93, studlab=study,
                 sm="RR", method="I")
meta1

metacum(meta1)
metacum(meta1, pooled="random")

forest(metacum(meta1, pooled="random"))