Displaying 20 results from an estimated 1000 matches similar to: "predict.rma (metafor package)"
2012 May 05
3
metafor
Dear users of metafor,
I am working on a meta-analysis using the metafor package. I have a
excel csv database that I am working with. I am interested in pooling
the effect measures for a particular subgroup (European women) in this
csv database. I am conducting both sub-group and meta-regression.
In subgroup-analyses, I have stratified the database to create a
separate csv file just for European
2013 Mar 19
1
Error when adding lines to a plot using the mixed-effect model and metafor package
Hi,
I am a student using R for my final year project, with the metafor package being particularly helpful. I have been following the steps laid out in the manual 'Conducting Meta-analysis in R with the Metafor package' (Viechtbauer, 2010) and applying it to my own data of infected Anopheles mosquitoes across Africa.
In particular, I am attempting to apply a mixed-effect model to my data
2017 Aug 18
1
Meta-regression of categorical variables
Dear metafor users,
I am working on a meta-analysis of reliability and the correlation associations.
I need some help about conducting categorical moderators variables.
Questions 1: How to conduct the weighted ANOVAs assuming a mixed-effects model on the tranformed alpha coefficients/the tranformes correlation coefficients for the categorical moderator variables?
Questions 2: How to
2011 Jul 18
1
Extract confidence intervals from rma object (metafor package)
Dear R-experts!
I am working on some meta-analysis using the metafor package. I would like
to extract values of the confidence intervals of the effect sizes of the
single studies from an rma object. Those values are printed out when
plotting a forest plot using the forest function on the rma object, however
I was not able to locate them.
Many thanks for your help!
Jokel
[[alternative HTML
2012 Jun 06
3
Sobel's test for mediation and lme4/nlme
Hello,
Any advice or pointers for implementing Sobel's test for mediation in
2-level model setting? For fitting the hierarchical models, I am using
"lme4" but could also revert to "nlme" since it is a relatively simple
varying intercept model and they yield identical estimates. I apologize for
this is an R question with an embedded statistical question.
I noticed that a
2012 Jul 24
1
Annotate forest plot 'forest.rma()' for meta-analysis with metafor package
Dear R-experts,
The forest.rma() function from the metafor package creates nice forest
plots for presenting the results of a meta-analysis. These plots can be
annotated for e.g. giving names to the columns. E.g. as in the
documentation of the package:
data(dat.bcg)
### meta-analysis of the log relative risks using a random-effects model
res <- rma(ai=tpos, bi=tneg, ci=cpos, di=cneg,
2009 Dec 04
1
z to r transformation within print.rma.uni and forest from the package metafor
Dear R community,
I'm using the ,metafor'-package by Wolfgang Viechtbauer (Version: 0.5-5) to
calculate random-effects meta-analyses using Correlations and Sample Sizes
as the raw data.
(By the way: Really a nice piece of work, Wolfgang! Thanks heaps.)
I specified the "rma.uni' function so that it looks like this:
MAergebnis<-rma.uni(ri=PosOutc, ni=N,
2012 Jan 14
1
metafor: weights computation in Mantel-Haenszel method
Dear R users,
In metafor 1.6-0, the Mantel-Haenszel method is implemented by the rma.mh() function. I have observed that the sum of the weights computed by weights(x) doesn't add to 100% when x is an object of class rma.mh. The consequences of this fact can be clearly seen when a forest diagram is drawn with forest(x), which calls weights(x) (or more precisely, the method weights.rma.mh()
2010 Mar 04
1
ifthen() question
Hi All,
I am using a specialized aggregation function to reduce a dataset with
multiple rows per id down to 1 row per id. My function work perfect when
there are >1 id but alters the 'var.g' in undesirable ways when this
condition is not met, Therefore, I have been trying ifthen() statements to
keep the original value when length of unique id == 1 but I cannot get it to
work. e.g.:
2010 Jan 04
1
metafor: using mixed models
Dear all,
I'm currently applying a mixed model approach to meta analysis using the
package metafor. I use the "model.matrix()" function to create dummy
variables. The option btt gives me the combined test for the dummies.
Problem is, I don't know which indices I have to use, and can't really
figure it out from the help file and the examples. I use following code :
X <-
2011 Jan 12
1
Metafor vs Meta vs Spreadsheet: wrong numbers
Hello,
I experimented the Metafor and Meta packages in the scope of replacing Excel
for meta-analysis. I performed the first working example provided in Michael
Borenstein's book "Introduction to Meta-Analysis" with Excel, Metafor and Meta.
The numbers given by my spreadsheet, which I validated from Borenstein's book,
conrespond quite closely to those given by Meta, but
2011 Aug 05
1
Main-effect of categorical variables in meta-analysis (metafor)
Dear R-experts!
In a meta-analysis (metafor) I would like to assess the effect of two
categorical covariates (A & B) whereas they both have 4 levels.
Is my understanding correct that this would require to dummy-code (0,1) each
level of each covariate (A & B)?
However I am interested in the main-effects and the interaction of these two
covariates and the dummy-coding would only allow to
2013 Mar 15
1
metafor - multivariate analysis
Dear Metafor users, I'm conducting a metaanalysis of prevalence of a particular behaviour based on someone elses' code. I've been labouring under the impression that this:
summary(rma.1<-rma(yi,vi,mods=cbind(approxmeanage,interviewmethodcode),data=mal,method="DL",knha=F,weighted=F,intercept=T))
is doing the multivariate analysis that i want, but have read that
2012 Aug 09
1
Factor moderators in metafor
I'm puzzled by the behaviour of factors in rma models, see example and
comments below. I'm sure there's a simple explanation but can't see it...
Thanks for any input
John Hodgson
------------------------------------- code/selected output -----------------
library(metafor)
## Set up data (from Lenters et al A Meta-analysis of Asbestos and Lung
Cancer...
##
2009 Aug 13
1
metafor random effects meta-analysis
Hello,
Great to see the new metafor package for meta-analysis.
I would like to perform a meta-analysis in which I initially calculate the intercept of the model with a nested random-effects structure. In lme, this would be
model<- lme(v3~1, random=~1|species/study, weights = varFixed(~Wt), method = "REML")
where multiple effects sizes are measured for some studies and more than
2011 Jan 12
1
metafor/ meta-regression
Hi I have tryed to do the meta-regression in metafor package, but I
would like to get the standardized coefficients for each variable, however in
command:
Ø res<-rma.uni (yi, vi,
method="REML", mods=~cota+DL+uso+gadiente+idade, data= turbidez)
I just have the coefficients no standardized (estimate) of the multiple
regression.
What I need to do?
Thanks
Fernanda Melo
2012 Sep 07
2
metafor package: study level variation
Hello. A quick question about incorporating variation due to study in the metafor package. I'm working with a particular data set for meta-analysis where some studies have multiple measurements. Others do not. So, let's say the effect I'm looking at is response to two different kinds of drug treatment - let's call their effect sizes T1 and T2. Some studies have multiple
2012 Aug 02
2
metafor- interpretation of moderators test for raw proportions
Hello metafor users,
I'm using metafor to perform a single-effect summary estimate of the raw
proportion of patients experiencing a post-operative complication, and I'm
interested in seeing if this proportion differs between the three most
commonly used surgical techniques. The software is working as expected, but
I would like to double check on the interpretation of my mixed-effect model
2013 Jan 23
1
mixed effects meta-regression: nlme vs. metafor
Hi,
I would like to do a meta-analysis, i.e., a mixed-effects regression,
but I don't seem to get what I want using both the nlme or metafor packages.
My question: is there indeed no way to do it?
And if so, is there another package I could use?
Here are the details:
In my meta-analysis I'm comparing different studies that report a
measure at time zero and after a certain followup
2012 Sep 27
1
What to use for ti in back-transforming summary statistics from F-T double square-root transformation in 'metafor'
Hi Dr. Viechtbauer,
I'm doing meta-analysis using your package 'metafor'. I used the 'IRFT' to transform the incident rate. But when I tried to back-transform the summary estimates from function rma, I don't know what's the appropriate ti to feed in function transf.iirft. I searched and found your post about using harmonic mean for ni to back-transform the double