Questions tagged [meta-analysis]

Methods focused on contrasting and combining results from different studies, in the hope of increasing precision and external validity.

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Meta-analysis with pre-weighted data

does anyone know of any references that speak about whether studies can be included in a meta-analysis if the study is already given some kind of weighting factor? For example, large scale survey ...
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What is the formula for combining Hedges' g across studies?

If I have Hedges g for a bunch of different studies, what is the formula for combining them? EDIT with more detail. This is part of a meta-analysis. Each study was small, with N usually equal 6 or 8 ...
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'rma.mv' function output- fisher Z or raw correlation

I would like to ask a question regarding the output of the rma.mv function. I had raw correlations which I transformed into Fisher's Z correlations using the 'escalc' function. Then, I performed a ...
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Is the shrinkage of subgroup analyses in meta-analysis an example of Stein's paradox?

This paper writes (edited for concision): Consider, a doctor in Germany confronted by a meta-analysis of long term‚ $\beta$ blockade after myocardial infarction. Although a robust beneficial effect ...
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Selecting the correct clustering variable when calculating robust meta-analytic tests and error terms for dependent data [closed]

Background I am revising a meta-analysis for publication and have been asked to adopt a multivariate modelling approach using the rma.mv and robust functions within the metafor package in R. ...
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Pseudoreplication in studies used in meta-analysis (problem with sample size)

We are conducting a meta-analysis, but we have problems with pseudoreplication within our primary studies. Most of the studies use correlation analysis (but we also have linear regression and GLMM) ...
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41 views

Different results meta vs metafor

I'm running a meta-analysis of single proportions. I know this can be done in both meta and metafor but I am getting slightly different results using both the moment I add in smaller studies. Suppose ...
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30 views

Analysis of pre and post treatment

I have the following data: A random group of patients with a certain disease who receive a drug at a certain time. Dose of the drug given to the patient. This drug has an affect to the heart which ...
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How to calculate mean (SD) from different values for a meta-analysis

For a "meta-analysis" i would like to sum up the result from 6 studies. Still values stated in these studies are median (IQR), mean (SD), mean (range), mean (95% CI). Do I have a chance to calculate a ...
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How to manage publication bias

my team has been carrying out a meta-analysis study. Through the process, who have statistically detected publication bias, according to Egger's regression test; to consider the suppressed studies to ...
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best subset of moderators for meta-analysis in R

I have a large number of "categorical" moderators (35 moderators). I am planning to use the best subset of these moderators that can maximally explain the variation in my 257 correlated effect sizes ...
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Meta-Analysis: Effect size calculation - p-value

Is it possible to calculate an effect size if only a p-value and sample sizes of two independet groups are given? Kind regards Joanne
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Meta-analysis for complex data with many treatments (and often no controls)?

I'm planning to conduct a meta-analysis of the catches of invertebrates from various types of sampling methods - with the question of: 'which method catches the most inverts?' In a preliminary ...
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115 views

Why do we log transform response ratios?

In meta-analysis, it seems a standard practice to take the natural log of the response ratio before evaluating it. My question is why? That is, if I have a treatment mean (Xe) and a control mean of ...
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P-Uniform* interpretation

I have a question concering the interpretation of my p-uniform* results. So this is my results: Estimating effect size p-uniform* ...
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1answer
15 views

Controlling for baseline differences?

I am comparing two groups, with data before and after retirement, to see the effect retirement has on depression levels. The control group works over the two measurement points, and the retirees ...
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To pool or combine multiple correlations: Pearson and ICC

For part of a study we are running, we are investigating the correlation between a post-practice score, and the subsequent day's pre-practice score. We are looking at the potential association between ...
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1answer
36 views

Meta - Analysis - Effect size calculation

I am trying to include a study into my meta-analysis, that reports results of an ANOVA: F(1,76) = 11.23, p = 0.001, n²=0,13 My question is how to calculate Hedge g from this data? I work with R, using ...
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Fixed vs. Random effects meta- regression [closed]

how to understand the differences between fixed vs. random effects meta-regression? Not meta-analysis.
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Effect size for meta-analysis from ANOVA with significant interaction term

For a meta-analysis, I found a study in which the main effect of A on my dependant variable was not significant but the interaction of A and B and the interaction of A, B and C were. I also have only ...
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1answer
28 views

Calculating SMD from posttest only - is this possible?

I am performing a meta-analysis (with 'metafor' R-project) as described by Becker (1988), and I compute the standardized mean change for a treatment and control group. I compute a (standardized) ...
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Calculation of I-squared in meta-analysis of diagnostic accuracy

I would like to calculate heterogeneity statistics (Cochran's Q, I-squared) for a meta-analysis of diagnostic accuracy. I successfully used the 'mada' package in R to calculate these statistics, but ...
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How to compare fixed effects of linear mixed models

I have two linear mixed models that I ran with the lmer function from the lme4 package. The models are identical except that I ...
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Statistical test to compare two proportions

I am performing a meta-analysis comparing proportions of patients diagnosed with a disease based on 2 different diagnostic criteria. I have collected and pooled proportions rates (patients with a ...
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Simple Bayesian meta-analysis in R [closed]

Is there a simple way to conduct a Bayesian meta-analysis in R in order to support equivalence between the effects of two study types? E.g., Bayes factors would be perfect. So, for example I have ...
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1answer
24 views

Meta Regression- Average AGe

I want to conduct a meta-regression, using the variable. The studies in my meta-analysis include studies, that compore two indipendent groups. My question: to calculate average age of a study - is it ...
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1answer
43 views

Meta-Analysis - Calculating SE from given ES

I have the following problem. I am trying to conduct a meta-analysis and I have an effect size estimation of some unpublished studies. Unfortunately, I don't have the Standard Errors for the mentioned ...
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What transformation can I use to enable a relatively unbiased meta-analysis of $\alpha$ reliability?

I want to meta-analyse reliability estimates. For simplicity, assume the reliability estimate in question is Cronbach's $\alpha$ (aka Guttman's $\lambda$-3). Various packages exist to do meta-analyses ...
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Pseudo replicas in meta-analysis [closed]

How do i control pseudo replicas in meta-analysis studies? I know I can randomize samples using Bootstrap for example, but how do I do this? Any clarification will be most welcome!
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Correcting for reliability scores for Hedges g

I've received a revise and resubmit on my meta-analysis investigating the effects of a positive psychology intervention on depression and anxiety symptoms. I used Hedges' g as the effect size within a ...
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Summary effect size of multiple dependent effect sizes

Problem Statement I am currently conducting a meta-analysis. At the moment, I am just calculating the effect size for each included study (for our purpose we chose the correlation coefficient r). ...
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Can multilevel meta analysis be random-effects model and/or fixed effects model?

I am learning multilevel meta-analysis (or, three-level meta-analysis e.g., https://bookdown.org/MathiasHarrer/...
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42 views

Pooled analysis of studies with only intervention arm

I want to perform a pooled analysis of studies including only a treatment arm, so no proper control groups are available. Studies present data about subjects before the treatment and after treatment, ...
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93 views

How to convert beta from logistic regression into cohen's d?

Is there a way to transform a coefficient from a logistic regression into a cohen's d value? I am trying to calculate the cohen's d for a study with a binary DV while controlling for another ...
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35 views

How to convert sampling sampling variances for a meta-analysis using raw means as effect sizes?

I am conducting a meta-analysis using raw mean scores as effect sizes (i.e., reported test scores on a certain standardized test). I found a calculation formula for sampling variances provided by, e....
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63 views

Meta-analyses using raw mean as Effect Size, instead of mean differences (e.g., Cohen's d)

I am writing up my meta-analysis using raw mean scores as effect sizes (i.e., reported mean scores on a certain standardized test) using the metafor package in R. ...
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Trelllis plots in meta-analsysis [closed]

I am trying to plot, a trellis plot. But I get an error and I don't know what its means. ...
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Multilevel regression meta-analysis : no existing package? (Edited)

The question is in the title. Meta-analysis with binomial distribution I'm trying to do a meta-analysis on occurence of an event across different studies. For each study $i$ ($i=1,\dots,N$), I have ...
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11 views

How do I use clinical trials as random effects in a cox regression model stratified according to trial for an individual patient data meta-analysis? [closed]

I am performing an individual patient data meta-analysis and pooling several trials. I have the data all combined in a single data set and want to fit it in a Cox regression model stratified according ...
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1answer
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Prediction Intervals by meta package

I am using meta 4.9-5 package for conducting meta-analysis on correlation data. But I cannot figure out why it is unable to calculate lower and upper prediction intervals even I have set prediction = ...
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57 views

How to handle studies that don’t provide an estimate of effect size in a meta-analysis?

Say we want to survey the literature to find out the effect of Treatment A on Value B. Some studies provide an effect size estimate with confidence intervals and t-test results (e.g., “Treatment A ...
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Predicting disease based on eeg electrode power features and source power estimates

The dataset consists of Eeg electrode power features in all power bands(alpha, beta, delta..both relative and absolute) and source power features (obtained after source estimation) in addition to ...
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Why is Metafor R package giving an I2 for fixed effects meta-analysis model (rma.uni)? [closed]

I'm trying to run a fixed effects meta-analysis using the Metafor R package and in the documentation I read that it does not return an I^2 for fixed effects models, only for random effects models. ...
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2answers
148 views

Are there good alternatives to Cochran's Q test for heterogeneity in meta-analysis?

We used the Q test to determine heterogeneity with p-values <0.10. A highly recognised statistician commented that the Q test has low power and that it should not be used to determine presence of ...
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1answer
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Regression multi-level meta-analysis with binomial data in R: no existing package? [closed]

The question is in the title. Meta-analysis with binomial distribution I'm trying to do a meta-analysis on occurence of an event across different studies. For each study $i$ ($i=1,\dots,N$), I have ...
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1answer
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What's the statistical method of comparing the amount of pre-post difference scores of between groups?

I am currentnly doing a meta-analysis of the effects of social cognitive training on social cognitive function of patients of schizophrenia. There are wo conditions: treatment group receving social ...
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model test p-value>0.05 but intrcpt <0.05 [closed]

Mixed-Effects Model (k = 21; tau^2 estimator: SJ) tau^2 (estimated amount of residual heterogeneity): 0.2301 (SE = 0.0752) tau (square root of estimated tau^2 value): 0.4797 I^2 (...
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Assembling meta-analysis data with paired data for metafor

I am trying to assemble a meta-analytic dataset for computing yi and vi for metafor. For this dataset, I am including paired data (i.e., one sample of participants that completed upright and inverted ...
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Variance–covariance matrix in meta-analysis of variation metafor

I'm conducting a meta-analysis on estimating a gold standard measure from other simpler measures. To determine the error of estimation, I derived the standard deviations of the differences between the ...