Questions tagged [metafor]

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meta-analysis with point-biserial correlation using metafor

I would like to conduct a meta-analysis on the association of a continuous and a dichotomous variable. In order to compare the result with previous meta-analysis I woud like to use the point-biserial ...
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1 vote
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34 views

Egger's test, Trim and fill method and funnel plots for three-level meta-analysis

I have performed a three-level meta-analysis in R (based on correlations) to estimate an overall association and to perform moderator analyses following guidelines of Assink & Wibbelink (2016). ...
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2 votes
0 answers
13 views

Arm-based meta-analysis of variation and mean with interval scale data

I’ve been extracting data for an arm-based meta-analysis on the distribution of a self-report survey in various research contexts. I am interested in the approach taken in Nagakawa et al. (2015), ...
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37 views

How to calculate the proportion of heterogeneity accounted for by moderators in a multi-level random-effects meta-analysis?

I have conducted a multi-level random-effects meta-analysis using the "metafor" package in R and have been asked by a reviewer to report the proportion of heterogeneity accounted for by ...
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1 vote
1 answer
96 views

Including multiple treatment and multiple endpoint studies in meta-analysis using metafor

I am running a random-effects multivariate meta-analysis with the package metafor. I have binary data with one treatment and one control group. I am interested in the overall effect of the treatment. ...
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1 vote
1 answer
43 views

Three-level Meta-Analyses: correlation comparisons and correction for publication bias?

I'm conducting a three-level meta-analysis on correlations using the {metafor} package on R. I'm quite a newbie when it comes to three-level meta-analyses, so I have two doubts. 1) From each study, I ...
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1 vote
1 answer
52 views

Meta - analysis for paired data (individual patient data, IPD)

I've got data for three experiments, pre-post data, where I have all the individual level data (not shown). I want to produce a comparison with summary data in the form of a meta-analysis and forest ...
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0 answers
41 views

How to meta-analyze incremental validity

Suppose we have two instruments (A and B) and we want to meta-analyze whether instrument B has incremental validity over instrument A in predicting an outcome Y. What effect size would be most ...
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2 votes
1 answer
83 views

Meta Analysis in R (metafor): How to interpret a multi-level mixed effects model with intercept and without intercept?

Dears, I am having trouble making sense of two MLMEs I did using rma.mv(). I am using a factor variable with 4 levels as a moderator. The two outputs (once with ...
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0 answers
24 views

Meta Analysis (metafor in R): Difference between Mixed-Effects Models that have an intercept and those who don't? [duplicate]

My question is more theoretical, less code related. I am trying to enter some moderators to rma.mv() , my moderators are: 1 factor with 4 levels. Call it "F&...
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3 votes
0 answers
48 views

Why are GLMMs distinct from GLMs for Meta-analysis of study level data?

Would anyone be able to explain conceptually why GLMMs with a random intercept at the study level are occasionally used for meta-analysis of proportions / counts, when the observations are already at ...
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4 votes
1 answer
178 views

Egger's regression test for funnel-plot asymmetry in a meta-analysis using metafor

My meta-analysis investigates the association between dietary intake of a micronutrient on the risk of being diagnosed with a disease (binary outcome). I am trying to test for funnel-plot asymmetry of ...
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2 votes
1 answer
35 views

Standard Error of Mean Effect Size with User Supplied Weights (metafor)

I am trying to estimate a fixed-effects model with user-specified weights and am a bit confused as to how metafor is calculating the standard error of the summary effect. The mean effect of the output ...
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3 votes
1 answer
88 views

Doubt regarding Funnel plot in Meta Analysis using Metafor in R

II tried to do a Funnel plot of a dataset for a disease-prevention paper, view dataset here. Got the plot, but am worried it is wrong.The dataset contains the ...
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2 votes
1 answer
35 views

Extracting repeated measures standardised difference from studies for meta-analyses (unknown correlation between measures)

I am conducting a meta-analysis and trying to extract standardised differences from a study using pre-post (or repeated measures) design. I am given the Mean, SD, and Sample Size for the pre- and post-...
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1 vote
1 answer
37 views

Harbord test in metafor package in R

I'm hoping to implement Harbord's method (https://onlinelibrary.wiley.com/doi/abs/10.1002/sim.2380) for evaluating publication bias using the 'metafor' package in R. It appears this is possible (https:...
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1 vote
0 answers
21 views

How do i perform a meta-analysis of prevalence rates using metafor package (with no treatment group)? [closed]

I have a spreadsheet with this type of information: ...
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3 votes
2 answers
63 views

metafor's rma gives conflicting (zero) values for tauˆ2 and Iˆ2 compared to Review Manager?

I'm having a problem with metafor's rma-function, which inappropriately (I suppose!) gives both tauˆ2 and Iˆ2 zero values. This questions was previously asked on Stack Overflow, and then it was ...
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1 vote
0 answers
54 views

How can I calculate the variance of the log odds ratio for meta-analysis with multiple trials per participant?

Background I am performing a meta-analysis of priming studies, where participants receive one of two primes and then produce one of two responses. In these studies, each participant completes multiple ...
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0 votes
0 answers
23 views

Aggregating estimates from interdependent studies across multiple clustering variables (meta-analysis)

I'm currently working on a meta-analysis using Metafor and am seeking assistance to address dependence in the data. In more simple cases (e.g., one study with two patient subgroups), we have ...
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1 vote
0 answers
29 views

What data type is needed for a meta-analysis?

I have a student who has compiled field data from agricultural studies across parts of Africa. She wants to conduct a meta-analysis to determine if cropping system type is having an impact on crop ...
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0 votes
0 answers
27 views

Is there also an escalc function to calculate standardized means? [metafor]

I would like to use the metafor package to calculate my effect size. I am looking to calculate a "standardized mean" as I only have one quantitative outcome variable, which is sometimes ...
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0 answers
30 views

How to conduct subgroup analysis for multilevel meta-analysis model?

I would like to compare meta-analytic estimates from 2 subgroups using the metafor package. I came across this helpful guide, but I am using multi-level models (for multiple effect sizes within ...
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1 vote
0 answers
14 views

Can I pool studies in a meta analysis with binary and continuous outcomes? [duplicate]

I'm currently completing a meta-analysis (in r using the meta/metafor package) looking at predictors of treatment response in patients suffering from a particualr mental disorder (psychosis). Some ...
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1 vote
1 answer
90 views

How to back-transform regression coefficients in a multi-level meta-regression in metafor

My question is an extension of this one, where I asked about back-transforming the results of a reliability generalization meta-analysis. I have run a three-level meta-regression, using the Bonett-...
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3 votes
2 answers
291 views

Why is there a discrepancy between the underlying meaning of variance between basic statistics and meta-analyses?

Normally, I would say that variance (and, in extension, standard deviation since it's just the square root of the variance) refers to a measure of deviation that describes how data points within a ...
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1 vote
0 answers
27 views

A reasonable choice of effect size for a meta-analysis

I'm doing a meta-analysis where the studies ask the study participants to read, find, and correct the wrong words in a text. Some studies score each study participant's performance on the text using: ...
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3 votes
1 answer
51 views

comparing effect sizes (partial correlations) for multiple outcomes in a meta-analysis

I'm conducting a meta-analysis using the metafor package. I'm using partial correlations and I'm interested in two effects - correlations between X and Y1 and X and Y2 (both controlling for Z). I have ...
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1 vote
0 answers
82 views

Specifying a complex random-effects structure in metafor

I am working on a project in which I am using metafor to carry out a single-paper meta-analysis. My project contains data from 5 different studies; each study ...
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1 vote
0 answers
68 views

Specifying two-level Random Effect model with rma.mv in metafor [closed]

I am having some trouble understanding rma.mv in R which I would like to use for my first meta-analysis. I have got about 40 studies where I can extract multiple effect sizes from e.g. because they ...
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2 votes
1 answer
113 views

Difference between Multilevel I^2 and ICC?

I have been using the excellent metafor package for a work-related project and for some reason there's a concept that I can't wrap my head around. In his guide (...
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1 vote
0 answers
70 views

Combining moderator variables in meta-regression

I have a meta-analysis type dataset of compiled information from primary studies; including hazard ratio's and confidence intervals together with predictors (i.e. "moderators" in the context ...
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2 votes
1 answer
79 views

Back-transforming meta-analysis results in metafor

The R package metafor offers various ways of back-transforming the results of a meta-analysis with a transformed effect size/...
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2 votes
1 answer
58 views

How to test for contrasts and interpret multiple meta-regression in metafor

Lets say I was meta-analysing studies which have assessed the influence of a warm- up on running performance (completely hypothetical). Lets also say that I wanted to find out whether pre-exercise ...
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1 vote
1 answer
61 views

Reliability Meta-Analysis/Reliability Generalization: Mixing Methods for Calculating Transformations, Sampling Variances, and Weights

I am currently planning a reliability meta-analysis or reliability generalization study (Vacha-Haase, 1998). I write this question assuming a random-effects model has been selected and Cronbach's a is ...
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1 vote
0 answers
69 views

Presenting raw hazard ratios, not log(hazard ratio), in forest plot for meta-analysis using metafor

I'm trying to perform a meta-analysis in R with metafor of trials for which the hazard ratios(HR) and 95% CI are available as outcomes. I am aware that I have to use log(HR) for calculation, but I ...
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1 vote
0 answers
33 views

When conducting a moderation test in a meta-analysis, should you include a category including only 1 study?

I am conducting a moderation test as part of a meta-analysis and the moderator variable is categorical. One of the levels in the categorical moderator comprises only one study (though there are ...
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2 votes
0 answers
60 views

Meta-regression analysis of the correlation between dependent variables

I have a set of studies which report a biomarker and an incidence of an outcome at baseline and at end of follow-up. I would like to get a measure of how much the change in the biomarker(chg_bm) ...
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1 vote
0 answers
38 views

Model selection for Multivariate random effects models in metafor

I am currently in the process of trying to run a multivariate meta-analysis model in metafor with random effects. I have no previous experience working with meta-analysis models and have read many ...
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1 vote
0 answers
26 views

What is the type A uncertainty from a DerSimonian Laird estimator?

When averaging independent results, the type A uncertainty can be estimated as the standard error of the mean, $$\frac{\sigma}{\sqrt{n}}$$ where $\sigma$ and $n$ are the standard deviation and the ...
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4 votes
1 answer
85 views

Why are $R^2$ values not available in fixed effects meta regressions

I'm currently conducting a meta-regression for my moderators from a meta-analysis my team recently conducted. In calculating the fixed effects meta-regressions, my objective is to identify how much ...
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2 votes
1 answer
76 views

metafor: correlational output from multivariate meta-analysis question

I have a quick question about the metafor package. I have been using the author's guide for stochastically dependent effect sizes (via github) to run a [multivariate meta-analysis][1] using multiple ...
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1 vote
1 answer
39 views

Overall treatment effect from a mixed model in metafor

This is in continuation of my previous post (Testing the effect of moderators in metafor package) Thanks@Wolfgang for the clarification. Now I used model: A<-rma.mv(yi, vi, mods = ~ factor(soil)+...
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1 vote
0 answers
112 views

Random slopes in rma.mv

I'm trying to figure out whether my metanalysis needs random slopes. I used the package lmer function from the lme4 package to model two types of regression: 1.- Only random intercepts, 2.- Random ...
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1 vote
0 answers
58 views

Multilevel-CCREM model with standardized predictors

Background: I'm conducting a multilevel metanalysis to see if different types of magnetic fields, with different intensities and exposure duration, affect plant growth parameters. I have effect sizes (...
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3 votes
1 answer
190 views

Pooling different effect sizes in meta-analysis with metafor

Simple question here. Suppose that I have 20 papers to be included in a meta-analysis, which compare the risk of death with 2 treatments, A vs. B. For 15 of them, I only have number of events and ...
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1 vote
1 answer
47 views

Using both fixed effects and random effects in r metafor package

Hi there :) I am trying to run a meta analysis using rma.uni in the metafor package in r but cannot work out how to add both fixed effects (eg bird migration status) and random effects (eg species, ...
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1 vote
1 answer
337 views

Testing the effect of moderators in metafor package

I am conducting multilevel meta-analyses in R using the metafor package. I have 177 treatment vs. control comparisons from the data from 30 studies (multiple rows per study due to multi-year studies). ...
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1 vote
1 answer
72 views

R Metafor Measure = MN

In R Metafor package, there is a way to use the escalc function to calculate the effect sizes for a single group design using measure = MN. My question is how can I find studies that derived the y and ...
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1 vote
0 answers
123 views

Conducting a meta-analysis of proportions and one proportion is negative

I am conducting a meta-analysis of proportions and plan to first use the Freeman-Tukey double arcsine transformation before meta-analysing the data. However, one of the proportions is negative (-1.3%)....
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