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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Does it make sense to fit a nested model if some nested factors only have one level?

I am trying to build a meta-analytic model (using metafor package in R) to analyze effect sizes extracted from multiple studies (I have about 300 effect sizes from ...
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Does the forestplot function in R use fixed- or random-effects modelling? [closed]

I'm using the forestplot function in R for my meta-analysis and trying to determine whether it uses fixed or random effects modelling. I've checked the documentation but can't seem to find the ...
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Aggregating results from multiple unsupervised clustering studies

Is there a framework, similar to meta-analysis, to interpret or aggregate the results from multiple unsupervised clustering studies? For example, take two studies on evaluating patients with heart ...
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How to fit Frequentist meta-analysis for regression between endpoints?

General Information I have $j = 1, \dots J$ studies which report two measurements, $x_{obs, j}$ and $y_{obs, j}$, and their standard errors, $\sigma_x$ and $\sigma_y$. Both measurements are assumed to ...
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Do estimates of effect size vary as a function of sample size?

Imagine 50 studies of the same phenomenon with 100 participants, vs. 50 studies with 200 participants. Would we expect greater variation in estimates of effect size with a smaller number of ...
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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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Metanalysis in R for writing interventions

I do a metanalysis (the subject is writing interventions for students with Learning Disabilities) in R package. Due to the use of continuous variables, the effect size I used was the Standardized Mean ...
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Multi-level meta-anlaysis

I'm conducting a meta-analysis in which some of studies reported multiple effect size as they examined the outcome on multiple groups of glucose-lowering drugs. So, a three-level meta-analysis was ...
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Can I compare two other correlation coefficients in one meta-analysis?

I am in the process of initial research into the relationship between blood pressure and the PPG signal parameter. I have two groups of articles that describe: 1) the correlation coefficient between ...
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1answer
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Meta analysis of control groups

I am conducting systematic review to establish control value of a new diagnostic variable (continuous data). I would like to do sub-group analysis as well. Since it is only for control group, is meta-...
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Is it possible to perform a meta-analysis on the SEE generated from models?

Let's say you were interested in performing a meta-analysis on the predictive validity of various simple linear regression models which differed in the method of extrapolation. One of the main metrics ...
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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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How can I compare two response ratios in meta-analysis?

For example, there are several studies about how males and females response to certain condition. Here's the data I got: Xmc, the mean data of male control group, Xfc, the mean data of female control ...
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Data transparency in a meta-analysis

In a meta-analysis project, we extracted data from published papers. Now, we are going to submit it in a journal. But, in the Declarations section, the journal requires a statement for "...
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Using hedge's g from a meta-analysis to calculate required sample size for a paired t-test

In this meta analysis the authors quote an overall Hedge's g effect size of $g=1.116$ for the effect of transcranial magnetic stimulation (TMS) on cocaine and methamphetamine use. Seems dubious to me ...
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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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How to choose between different estimators for tau in meta-analysis?

The question is relatively simple although it may won't be possible to answer at all. In meta-analysis using random-effect model, we can choose between several different methods for estimating tau (e....
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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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How to do a meta-analysis to synthesise studies across more than 2 variables?

Are there meta-analysis texts that deal with how to synthesise studies across more than 2 variables, and which also includes synthesising primary studies that deal with more than 2 variables at the ...
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Compare data from two experiments within single logistic regression to determine effect of experimental design?

I've run two studies. Study 1 (N = 112) examines the effects of two variables (A and B), each of which have two levels (a1, a2; b1, b2). For each variable, I'm interested in the effect those different ...
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1answer
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What type of correlations should be entered when doing mini meta analysis using meta package (metacor) in R?

I am doing a mini-meta-analysis of four correlational studies. In the estimated model I have three predictors and one DV. Using the meta-package in R, I use the following code to test the link between ...
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Meta-analysis_studies with within and between study design

I am trying to run a meta analysis based on the question if physical activity leads to an increase in cognitive functioning. I have studies that report mean and standard deviations for the ...
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Can a grouping variable also be a predictor or vice versa

I sometimes see that a grouping variable such as study ($1,2,...15$) is used as a grouping variable to the right of the |: ...
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How to run meta-analysis for simple linear regression coefficient

I have run several independent studies to look at the relationship between a continuous predictor variable X (ranging from 0 to 100) and a continuous outcome variable Y (ranging from 0 to 10). (...
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If the variance of residuals is known, then can we add an extra random effect?

In random-effects meta-regression, we often model an estimate of effect size ($effectSize_i$) as: $$effectSize_i=\mu+u_i+e_i$$ where $u_i \sim N(0, \tau^2)$, and $e_i \sim N(0, v_i)$, where $\tau^2$ ...
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Sequential hypothesis test for uniform distribution

Suppose I have a sequence of data points $x_1,x_2,\dots$. I want to do a sequential hypothesis test, were the null hypothesis is that each $x_i$ is iid uniform on $[0,1]$, and the alternative ...
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Meta-analysis on percentage of total calorie intake

We are looking at a number of studies which have profiled nutrient information which contributes to total daily calorie intake. For example, fibre might make up 5% of daily total calorie intake. My ...
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How to correctly interpret coefficient of a multiple meta-regression in metafor?

When fitting a multiple meta-regression in metafor, the output shows multiple coefficients, for each predictor. To make an example, similar to what is done here: https://www.metafor-project.org/doku....
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Meta-analysis of linear and non-linear associations: R2 as the “effect size”?

I have a question regarding meta-analysis of effect sizes of associations. I was wondering whether it is possible to compare results across studies that modelled the association between two variables &...
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1answer
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Is it better to meta-analyze number of events or adjusted summary data (i.e. aHR)?

This question is not related to any example in particular - it is more like a "methodological" matter, which I feel may be useful to discuss. If we are conducting a meta-analysis on the ...
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Way to calculate the variance or SE of correlation from Fisher's z

Is there any way to get the sampling variance of correlation given Fisher's z and its variance? To make it more clear: suppose z = 0.5493 and ...
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1answer
51 views

How to interpret a meta-regression with a moderator which can vary between fixed values in Metafor

This question is slightly related to another one (Metaregression on meta-analysis of proportion with metaprop and metafor), but concerns the particular situation in which one moderator is a variable ...
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Metaregression on meta-analysis of proportion with metaprop and metafor

[EDITED for more clarity] I performed a meta-analysis of single proportion with logit transformation, which I made using the metaprop function, with a random ...
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How to convert variance of lnRR into percentage?

Currently, I'm working on meta-analysis using the log-response ratio (lnRR) as my effect size. As indicated in Pustejovsky (2017), one can convert ...
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What are the QE and QM testing in a meta-analysis, and how do they relate to each other?

I am working on a meta-regression model with a moderator variable (a factor), and so am using the QE and QM tests to explore the importance of the the moderator. I understand the QE tests for residual ...
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1answer
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Meta analysis- multivariate or multi-level model?

I am conducting a meta-analysis to understand the impact of an intervention X on people’s responses as measured by three categories of measures. I have a couple of questions regarding the methodology: ...
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1answer
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Is it possible to calculate hazard ratio from median survival time?

I am trying to perform a meta-analysis on time-to-event data. However, some studies only provide median survival time with 95% CIs. (for example, 5.54 +- 1.23 months) Is it possible to use these data ...
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Meta-analysis: how to combine main and interaction effects

I would like to conduct a meta-analysis to understand how an intervention A affects a desired outcome. While collecting data from the studies, I have noticed that some look at the direct effect of A ...
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To what degree does reproducibility of research differ across disciplines?

Have there been any statistics meta studies that compare the reproducibility of results, as well as the willingness of researchers to provide reproducible data, analysis, and code, in their studies ...
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Defining a threshold using aggregate data

I hoped for some advice - sorry if this is a very daft quesion. I have aggregate data on a medical test taken in both healthy people & patients with disease. The test provides a result on a scale ...
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Reference category and reporting of restricted cubic spline meta-regression output in metafor

I tried to fit a non-linear meta-regression model with a restricted cubic spline using the package "metafor" in R, as reported in here: https://www.metafor-project.org/doku.php/tips:...
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1answer
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How to meta-analyze latent correlations when r=1?

I compiled 11 correlations from k=11 studies. Let's just call the two variables $A$ and $B$. The correlations were very high and ranged in between $r=.54-.84$, but there is one study that reported a ...
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Converting standard error to sampling variance for meta-analysis

Is it possible to get sampling variance (vi) from a standard error for meta-analysis. Specifically, I am unable to obtain raw data from the computation of an SMD. However, the SMD and confidence ...
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What are some plausible criteria for starting a statistical meta-analysis process?

Before stating the problem, let me indicate my background so the community can understand my capabilities, or lack thereof. I am a trained biologist. However, during my bachelor's I studied many CS ...
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effect size for meta-analysis when study data violate normality assumptions?

I'm looking for advice regarding what effect size to use for meta-analysis. Our question is whether the number of individuals in a group increases per-capita productivity of that group. Studies are ...
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meta-analysis combining categorical and continuous measures of predictor variable

I'm beginning a meta-analysis. Our response variable is a continuous measure (a measure of colony efficiency), and the predictor variable is the number of individuals in a social insect colony. In ...
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1answer
28 views

Normally distributed effect size

I have read in several articles that effect sizes (like Cohen's d or Hedges g) can be considered to be normally distributed around the population effect size for large samples. On what basis can we ...
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Interpreting meta-regression outputs generated using metafor package

I have been using metafor package to conduct my meta-analysis. I'm quite naive with R software and hence having some difficulty in interpreting the output file generated for meta-regression. I have ...
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Is there a minimum variance for metafor::rma.mv()?

I want to run a three-level meta-analysis model of observed data with Measurement as a nested level of Study (independent samples, only source of covariance being the study group measuring them) using ...
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1answer
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When conducting a meta-analysis using Pearson's R as the effect size, should you include perfect values (i.e., r = 1.00)?

I'm in the process of conducting a meta-analysis of clinical research. Since most of the included studies report Pearson's R as the effect size, I've decided to use that as the meta-analysis statistic....

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