Questions tagged [metafor]
The metafor tag has no usage guidance.
52
questions
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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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34
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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
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13
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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
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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 ...
- 85
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96
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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. ...
- 11
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43
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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 ...
- 13
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1
answer
52
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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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41
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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
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answer
83
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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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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
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48
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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 ...
4
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answer
178
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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
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1
answer
35
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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 ...
- 23
3
votes
1
answer
88
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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 ...
- 41
2
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1
answer
35
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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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37
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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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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:
...
3
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2
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63
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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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54
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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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23
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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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29
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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 ...
Nicholas George
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27
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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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30
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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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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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answer
90
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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
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2
answers
291
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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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27
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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:
...
3
votes
1
answer
51
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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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answers
82
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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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answers
68
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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
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1
answer
113
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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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0
answers
70
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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
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1
answer
79
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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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58
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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
answer
61
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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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69
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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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33
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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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answers
60
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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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answers
38
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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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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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1
answer
85
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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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76
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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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answer
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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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112
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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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58
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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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190
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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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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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337
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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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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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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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