Print and summary method for objects of class meta
Description
Print and summary method for objects of class meta
.
Usage
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44  ## S3 method for class 'meta'
print(x, sortvar,
comb.fixed=x$comb.fixed,
comb.random=x$comb.random,
prediction=x$prediction,
details=FALSE, ma=TRUE, backtransf=x$backtransf,
pscale=x$pscale, irscale = x$irscale, irunit = x$irunit,
digits = .settings$digits, digits.se = .settings$digits.se,
digits.zval = .settings$digits.zval,
digits.Q = .settings$digits.Q, digits.tau2 = .settings$digits.tau2,
digits.H = .settings$digits.H, digits.I2 = .settings$digits.I2,
digits.prop = .settings$digits.prop, digits.weight = .settings$digits.weight,
warn.backtransf = FALSE,
...)
## S3 method for class 'metabias'
print(x, ...)
## S3 method for class 'meta'
summary(object,
comb.fixed=object$comb.fixed, comb.random=object$comb.random,
prediction=object$prediction,
backtransf=object$backtransf,
pscale=object$pscale, irscale = object$irscale, irunit = object$irunit,
bylab=object$bylab, print.byvar=object$print.byvar,
byseparator=object$byseparator, bystud=FALSE,
print.CMH=object$print.CMH, warn=object$warn, ...)
## S3 method for class 'summary.meta'
print(x, digits = .settings$digits,
comb.fixed=x$comb.fixed, comb.random=x$comb.random,
prediction=x$prediction,
print.byvar=x$print.byvar, byseparator=x$byseparator,
print.CMH=x$print.CMH,
header=TRUE, backtransf=x$backtransf,
pscale=x$pscale, irscale = x$irscale, irunit = x$irunit,
bylab.nchar=35,
digits.zval = .settings$digits.zval,
digits.Q = .settings$digits.Q, digits.tau2 = .settings$digits.tau2,
digits.H = .settings$digits.H, digits.I2 = .settings$digits.I2,
warn.backtransf = FALSE,
...)
cilayout(bracket="[", separator="; ")

Arguments
x 
An object of class 
object 
An object of class 
sortvar 
An optional vector used to sort the individual studies
(must be of same length as 
comb.fixed 
A logical indicating whether a fixed effect metaanalysis should be conducted. 
comb.random 
A logical indicating whether a random effects metaanalysis should be conducted. 
prediction 
A logical indicating whether a prediction interval should be printed. 
bylab 
A character string with a label for the grouping variable. 
print.byvar 
A logical indicating whether the name of the grouping variable should be printed in front of the group labels. 
byseparator 
A character string defining the separator between label and levels of grouping variable. 
header 
A logical indicating whether information on title of metaanalysis, comparison and outcome should be printed at the beginning of the printout. 
details 
A logical indicating whether further details of individual studies should be printed. 
ma 
A logical indicating whether the summary results of the metaanalysis should be printed. 
backtransf 
A logical indicating whether printed results
should be back transformed. If 
pscale 
A numeric giving scaling factor for printing of single
event probabilities, i.e. if argument 
irscale 
A numeric defining a scaling factor for printing of
rates, i.e. if argument 
irunit 
A character specifying the time unit used to calculate rates, e.g. personyears. 
bylab.nchar 
A numeric specifying the number of characters to print from label for the grouping variable. 
bystud 
A logical indicating whether results of individual studies should be printed by grouping variable. 
print.CMH 
A logical indicating whether result of the CochranMantelHaenszel test for overall effect should be printed. 
digits 
Minimal number of significant digits, see 
warn 
A logical indicating whether the use of

warn.backtransf 
A logical indicating whether a warning should be printed if backtransformed proportions and rates are below 0 and backtransformed proportions are above 1. 
bracket 
A character with bracket symbol to print lower confidence interval: "[", "(", "{", "". 
separator 
A character string with information on separator between lower and upper confidence interval. 
digits.se 
Minimal number of significant digits for standard
deviations and standard errors, see 
digits.zval 
Minimal number of significant digits for z or
tvalue, see 
digits.Q 
Minimal number of significant digits for
heterogeneity statistic Q, see 
digits.tau2 
Minimal number of significant digits for
betweenstudy variance, see 
digits.H 
Minimal number of significant digits for H
statistic, see 
digits.I2 
Minimal number of significant digits for Isquared
statistic, see 
digits.prop 
Minimal number of significant digits for
proportions, see 
digits.weight 
Minimal number of significant digits for
weights, see 
... 
Additional arguments. 
Details
Note, in R package meta, version 3.00 some arguments have been
removed from R functions summary.meta (arguments: byvar, level,
level.comb, level.prediction) and print.summary.meta (arguments:
level, level.comb, level.prediction). This functionality is now
provided by R function update.meta
(or directly in R
functions metabin
, metacont
,
metagen
, metacor
, and
metaprop
).
Review Manager 5 (RevMan 5) is the current software used for
preparing and maintaining Cochrane Reviews
(http://tech.cochrane.org/revman/). In RevMan 5, subgroup analyses
can be defined and data from a Cochrane review can be imported to R
using the function read.rm5
. If a metaanalysis is then
conducted using function metacr
, information on subgroups is
available in R (components byvar
, bylab
, and
print.byvar
, byvar
in an object of class
"meta"
). Accordingly, by using function metacr
there is
no need to define subgroups in order to redo the statistical analysis
conducted in the Cochrane review.
Note, for an object of type metaprop
, starting with version
3.70 of meta, list elements TE
, lower
and
upper
in element study
correspond to transformed
proportions and confidence limits (regardless whether exact
confidence limits are calculated; argument ciexact=TRUE
in
metaprop function). Accordingly, the following results are based on
the same transformation defined by argument sm
: list elements
TE
, lower
and upper
in elements study
,
fixed
, random
, within.fixed
and
within.random
.
R function cilayout can be utilised to change the layout to print
confidence intervals (both in printout from print.meta and
print.summary.meta function as well as in forest plots). The default
layout is "[lower; upper]". Another popular layout is "(lower 
upper)" which is used throughout an R session by using R command
cilayout("(", "  ")
.
Argument pscale
can be used to rescale proportions,
e.g. pscale=1000
means that proportions are expressed as
events per 1000 observations. This is useful in situations with
(very) low event probabilities.
Value
A list is returned by the function summary.meta
with the
following elements:
study 
Results for individual studies (a list with elements TE, seTE, lower, upper, z, p, level, df). 
fixed 
Results for fixed effect model (a list with elements TE, seTE, lower, upper, z, p, level, df). 
random 
Results for random effects model (a list with elements TE, seTE, lower, upper, z, p, level, df). 
k 
Number of studies combined in metaanalysis. 
Q 
Heterogeneity statistic Q. 
tau 
Squareroot of betweenstudy variance. 
se.tau 
Standard error of squareroot of betweenstudy variance. 
C 
Scaling factor utilised internally to calculate common tausquared across subgroups. 
H 
Heterogeneity statistic H (a list with elements TE, lower, upper). 
I2 
Heterogeneity statistic I2 (a list with elements TE, lower, upper), see Higgins & Thompson (2002). 
k.all 
Total number of studies. 
Q.CMH 
CochranMantelHaenszel test statistic for overall effect. 
sm 
A character string indicating underlying summary measure. 
method 
A character string with the pooling method. 
call 
Function call. 
ci.lab 
Label for confidence interval. 
hakn 
A logical indicating whether method by Hartung and Knapp was used. 
method.tau 
A character string indicating which method is used to estimate the betweenstudy variance tausquared. 
tau.common 
A logical indicating whether tausquared is assumed to be the same across subgroups. 
within.fixed 
Result for fixed effect model within groups (a
list with elements TE, seTE, lower, upper, z, p, level, df,
harmonic.mean)  if 
within.random 
Result for random effects model within groups
(a list with elements TE, seTE, lower, upper, z, p, level, df,
harmonic.mean)  if 
k.w 
Number of studies combined within groups  if 
Q.w 
Heterogeneity statistic Q within groups  if 
Q.b.fixed 
Heterogeneity statistic Q between groups (based on
fixed effect model)  if 
Q.b.random 
Heterogeneity statistic Q between groups (based on
random effects model)  if 
tau.w 
Squareroot of betweenstudy variance within subgroups
 if 
C.w 
Scaling factor utilised internally to calculate common tausquared across subgroups. 
H.w 
Heterogeneity statistic H within subgroups (a list with
elements TE, lower, upper)  if 
I2.w 
Heterogeneity statistic I2 within subgroups (a list with
elements TE, lower, upper)  if 
bylevs 
Levels of grouping variable  if 
title 
Title of metaanalysis / systematic review. 
complab 
Comparison label. 
outclab 
Outcome label. 
data 
Original data (set) used to create meta object. 
subset 
Information on subset of original data used in metaanalysis. 
prediction, level.predict 

comb.fixed, comb.random, print.CMH 
As defined above. 
version 
Version of R package meta used to create object. 
Author(s)
Guido Schwarzer sc@imbi.unifreiburg.de
References
Cooper H & Hedges LV (1994), The Handbook of Research Synthesis. Newbury Park, CA: Russell Sage Foundation.
Higgins JPT & Thompson SG (2002), Quantifying heterogeneity in a metaanalysis. Statistics in Medicine, 21, 1539–1558.
See Also
update.meta
, metabin
, metacont
, metagen
Examples
1 2 3 4 5 6 7 8 9 