metacont {meta}R Documentation

Meta-analysis of continuous outcome data

Description

Calculation of fixed and random effects estimates for meta-analyses with continuous outcome data; inverse variance weighting is used for pooling.

Usage

metacont(n.e, mean.e, sd.e, n.c, mean.c, sd.c, studlab,
         data=NULL, subset=NULL, sm="MD",
         level = 0.95, level.comb = level)

Arguments

n.e Number of observations in experimental group.
mean.e Estimated mean in experimental group.
sd.e Standard deviation in experimental group.
n.c Number of observations in control group.
mean.c Estimated mean in control group.
sd.c Standard deviation in control group.
studlab An optional vector with study labels.
data An optional data frame containing the study information.
subset An optional vector specifying a subset of studies to be used.
level The level used to calculate confidence intervals for individual studies.
level.comb The level used to calculate confidence intervals for pooled estimates.
sm A character string indicating which summary measure ("MD" or "SMD") is to be used for pooling of studies.

Details

Calculation of fixed and random effects estimates for meta-analyses with continuous outcome data; inverse variance weighting is used for pooling. The DerSimonian-Laird estimate is used in the random effects model. The mean difference is used as measure of treatment effect if sm="MD" – which correspond to sm="WMD" in older versions (<0.9) of the meta package. For the summary measure "SMD", Hedges' adjusted g is utilised for pooling.

The function metagen is called internally to calculate individual and overall treatment estimates and standard errors.

Value

An object of class c("metacont", "meta") with corresponding print, summary, plot function. The object is a list containing the following components:

n.e, mean.e, sd.e,
n.c, mean.c, sd.c, As defined above.
studlab, sm
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.
tau Square-root of between-study variance (moment estimator of DerSimonian-Laird).
method Pooling method: "Inverse".
level The level used to calculate confidence intervals for individual studies.
level.comb The level used to calculate confidence intervals for pooled estimates.
call Function call.

Author(s)

Guido Schwarzer sc@imbi.uni-freiburg.de

References

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

See Also

metabin, metagen

Examples

data(Fleiss93cont)
meta1 <- metacont(n.e, mean.e, sd.e, n.c, mean.c, sd.c, data=Fleiss93cont, sm="SMD")
meta1

meta2 <- metacont(Fleiss93cont$n.e, Fleiss93cont$mean.e,
                  Fleiss93cont$sd.e,
                  Fleiss93cont$n.c, Fleiss93cont$mean.c,
                  Fleiss93cont$sd.c,
                  sm="SMD")
meta2
[Package meta version 0.9-18 Index]