search for: metafor

Displaying 20 results from an estimated 41 matches for "metafor".

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2009 Aug 13
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") wher...
2009 Jul 24
I had found the author's (Wolfgang Viechtbauer) earlier meta-analytic code in R, MiMa, useful. so I have been exploring metafor using an example dataset from MiMa. metafor provides a lot more. However, MiMa provided parameter estimates, standard errors, z values, etc. for individual moderators in the meta-analysis, but I don't see how to obtain these from metafor. Have you any help about how to get this? Frank [...
2011 Oct 03
Meta-analysis of test statistics in "metafor" package?
...from a series of studies that tested for an interaction in a 2x2 anova. I'd like to test whether the 2x2 interaction is significant in the aggregate. Similarly, I have a matrix of chi-square statistics that I'd like to meta-analyze. How can I input these test statistics into the "metafor" package and conduct these meta-analyses? I see how to input raw data or standardizes effect sizes (e.g., d) into "metafor", but not test statistics. Best, David -- View this message in context:
2010 Nov 11
metafor: including phylogenetic non-independence among species?
Hello, Is it possible to include information about phylogenetic relatedness among species (when species are replicates for each study within a meta-analysis) in a meta-anlaysis in the metafor package? Alternatively, I wonder if the method f Lajeunesse 2009 American Naturalist has been adopted in R in any fashion? Thanks, Scott Chamberlain [[alternative HTML version deleted]]
2011 Aug 17
questions about "metafor" package
Hello,   I would like to do a meta-analysis with the package « metafor ». Ideally I would like to use a mixed model because I’m interested to see the effect of some moderators. But the data set I managed to collect from literature presents two limits.   -         Firstly, for each observation, I have means for a treatment and for a control, but I don’t always have co...
2012 Sep 07
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 ha...
2011 Jan 12
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. W...
2012 May 05
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,...
2012 Jan 14
metafor: weights computation in Mantel-Haenszel method
Dear R users, In metafor 1.6-0, the Mantel-Haenszel method is implemented by the 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 The consequences of this fact can be clearly seen when a forest diagram is drawn with forest(x),...
2013 Dec 12
refline in forest() {metafor}
...oticed that refline sets a vertical line indicating the null hypothesis. Is there a way to draw another vertical line, possibly dashed, centered on the summary estimate? Prof. Viechtbauer, if you happen to read this, I'd like to thank you for making an excellent package. I have been using the metafor package to do my first meta-analysis, having never used R before. The documentation is thorough and intuitive. Thanks, John John Williams ALB Candidate Harvard University Extension School johnwilliams at
2010 Dec 20
Metafor package
I have some question about metafor package. I'm interest to perform a random effect meta-analysis of proportion (single group summary of prevalence of disease in a population as reported by different study) It ask: 1. "PFT": The Freeman-Tukey double arcsine transformed proportion is reported to be equal to 1...
2012 Sep 27
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-trans...
2010 Jul 02
metafor and meta-analysis at arm-level
...level, the latter being the common way in which meta-analysis is done. By arm-level meta-analysis I mean one that accounts for data provided at the level of the individual arms of each trial and that does not simply derive the difference between arms and do the meta-analysis on that. I am not sure metafor can do that, but hopefully someone more experienced on it can clarify that to me. I can see that it can take data in both forms, arm and trial level, but it looks as if the arm-level information would be converted into trial one through escalc and the latter then used for the meta-analysis. Is that...
2012 Dec 31
a problem for metafor package
Dear sir or madam I want to know how to use "metafor"package do a meta anlysis, forest plot show the results of whole study and results of two subgroups like this the forest plot show in the attachment. looking forword to your reply Regards and Cheers Xudong Liu School of Public Health and Primary Care The Chinese University of Ho...
2013 Mar 02
Metafor "SMCR" Pre-Post Effect sizes
Dear all, I am very grateful that Wolfgang Viechtbauer implemented the standardised mean change for dependent groups. I was playing around a bit today, and I am not sure if I understand the "SMCR" procedure correctly. The documentation states that sd1i and sd2i are needed, but it seems to me that SMCR is ignoring sd2i (so Variances are not pooled). Instead, it uses sd1i (pre-test sd),
2011 Aug 05
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 tw...
2010 Aug 03
This is a question of clarification. IN 2009 Higgins, Thompson and Spiegelhalter (J R Statist Soc A 172:137-159) gave WinBUGs code to get credible intervals from random effects meta analysis for the prediction interval of a new study. It appears that the predict.rma function creates approximate credible intervals (pending a function revision by the author) for that purpose. Is my assumption
2013 Sep 15
FOSS licence with BuildVignettes: false
Dear All, I have been checking the metafor package against R-devel. R CMD check --as-cran metafor yields one note: FOSS licence with BuildVignettes: false Yes, I have 'BuildVignettes: FALSE' in my DESCRIPTION file. I see at Tue, 25 Jun 2013 CHANGES IN...
2012 Jul 24
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( ### meta-analysis of the log relative risks using a random-effects model res <- rma(ai=...
2011 Apr 11
forest + igraph ?
Hello, Is it possible to have two meta-plots in one graph (not par(mfrow=c(2,1))? But somthing like  library(metafor)  library("igraph")    if (interactive()) {     forest(dat.Treat$RR,$lower, ci.ub=dat.Treat$upper, xlab="Relative Risk",slab=dat.Treat$ID,refline=1)     forest(dat.Control$RR,$lower, ci.ub=dat.Control$upper, xlab="Relative Risk",slab=d...