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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1answer
394 views

Stratified logistic regression with log link

I noticed the other day that I can mimic a stratified logistic regression using a meta-analytic approach at least when there is only one stratification variable with two different values. This is the ...
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0answers
17 views

Phased Trial and Meta-Analysis [closed]

I'm currently conducting a meta-analysis of pharmacist-led health interventions and their effect on levels of medication adherence. One of my studies has a phased intervention design. This means that ...
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0answers
9 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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2answers
436 views

Making a Bayesian prior from a frequentist result

How should one go about turning a frequentist result into a Bayesian prior? Consider the following pretty generic scenario: An experiment was conducted in the past and a result on some parameter $\...
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0answers
17 views

Meta Analysis: how to compare RR, OR, HR

I have a 5 study dataset with 2 IRRs, 2 ORs and 1 HR, all with CIs given. Can I do a log transformation and then conduct a meta analysis. What is a plausible way to conduct meta analysis in this case
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1answer
16 views

Raw data reanalysis of multiple studies consider as meta analysis?

I am struggling with the question of how to define my research. I download raw data (RNA sequencing data) from multiple studies and I am going to analyze again them together as they " brought ...
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0answers
37 views

Ratio of means for a medical meta-analysis

I am in the process of pooling and analysing data from various studies for a meta-analysis I am working on. My supervisor (non-statistician) is keen for us to have the ratio of means which was ...
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1answer
79 views

Summary RR to % risk increase?

In a comprehensive meta-analysis the 'summary RR per 120 g/day increase in red meat intake was 1.20 (95% CI 1.04–1.38)' In a review citing this information, they have written rather 'a 20% increase in ...
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1answer
25 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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2answers
242 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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1answer
1k views

Calculating Cohen's d for pre-post/treatment-control design where treatment-control is also a repeated/within factor

I'm conducting a meta-analysis of studies that used pre-post/treatment-control designs. Most of them are mixed designs (pre-post is repeated/within; treatment-control is independent/between) with a ...
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1answer
2k views

Cohens d from Mixed method model - for the interaction term

I am doing a mixed method model: m1 <- lmer(DV ~ IV*Country + (1+IV:Country|Region), data = data) I am using the lme.dscore to get the Cohen's d for the model....
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2answers
46 views

I want to test for a significant difference in the result (t-value or effect size) of two paired t-tests

I am testing the quality of a measurement construct, where I propose that Measure A is better (i.e. more responsive to situational changes) than Measure B is. I conduct a study in which I measure the ...
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2answers
147 views

Calculate the standard deviation from a hazard ratio's confidence interval

I often come across hazard ratios and their confidence intervals in the published literature on clinical trials. I would like to calculate the standard deviation from these confidence intervals for ...
4
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2answers
95 views

Robust Variance Estimation in Bayesian Meta-analysis

BACKGROUND I am conducting a meta-analysis using the brms in R with structure akin to the following (leaving out priors, etc. ...
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0answers
15 views

Can I pool together data from two seperate RCTs of the same intervention when I have access to both datasets? If so, what analysis is appropriate?

Background I have available the data from: A parallel arm RCT of Intervention A compared to a control group that was conducted several years ago. The primary outcome is a difference in the post-...
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1answer
29 views

Is there a method/package that combines multivariate and network meta-analysis?

If you want to perform a meta-analysis on the general strength of the population and where each study can offer multiple outcomes (for example, measuring strength through deadlift capability and/or ...
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1answer
704 views

Is meta-analysis of odds ratios essentially hopeless?

In a recent paper Norton et al. (2018)$^{[2]}$ state that Different odds ratios from the same study cannot be compared when the statistical models that result in odds ratio estimates have different ...
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0answers
23 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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0answers
9 views

How to get 'overall' numbers in forest plot in meta analysis using STATA [closed]

I am trying to perform a meta-analysis. I put together the data, and I am creating a forest plot. I have several questions regarding how I can change the figure created by STATA. 1- After the studies ...
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1answer
24 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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0answers
19 views

Meta analysis Hazard Ratio with small number of studies (n=2)

I am doing a fixed effect meta-analysis pooling hazard ratios from 2 very similar cohorts. I understand that the inverse variance method is most commonly used to pool HR, however I also read that this ...
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1answer
57 views

What is the new sample size of a within study summary effect for outcomes with different sample sizes?

I am performing a meta-analysis and want to compute a summary effect (i.e. weighted mean) for studies that report data on more than one effect size. The same participants are involved, however the ...
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1answer
53 views

What is the justification for weighting meta-analysis by standard error instead of sample size?

I have observed in many meta-analyses, and in tutorials on the matter, that the analyzed studies are commonly weighted by the reciprocal of the standard error. This seems to have a face validity ...
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1answer
150 views

Why am I getting different means when conducting multilevel meta-analysis with factorial moderator vs. as subgroups?

I already asked about this in stackoverflow but maybe it fits better here. I want to conduct a multilevel meta-analysis using metafor in R. I have effect sizes ("esid") nested within samples ("...
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1answer
2k views

Comparing effect sizes across different data sets with non-normal data

I want to conduct a comparative analysis across a large amount of studies by looking at the effect sizes of their results with another variable. I am not too familiar with effect sizes so I'd ...
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0answers
19 views

Determining the standard deviation based on standard deviations from 2 data sets (paired)

I would like to run an analysis on the effectiveness of a drug on a specific parameter. In 1 study, mean and SD values were reported at baseline, and post-treatment for both experimental and control ...
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1answer
34 views

Interpret Generalized linear mixed model output

I've built a generalized linear mixed model due to non-normal data (no transformation will make it normal). I'm new to mixed models and I'm unsure how to report the output in a paper. Here is the ...
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1answer
944 views

Easy post-hoc tests when meta-analyzing with the `metafor` package in r

I am conducting meta-analysis using metafor in R. I would like to compare among 7 levels in a factor (i.e. different types of treatments). ...
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0answers
20 views

How to weigh a precomputed effect estimate according to its sample size in a meta-analysis?

I am currently conducting a meta-analysis in R with the intent to pool a standardized metric (i.e. defined daily dose (DDD) per 1000 inhabitant days) into a single forest plot. None of the studies ...
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0answers
59 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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0answers
27 views

Specifying random effects in multilevel meta-analysis with metafor package

I am running a meta-analysis in the R package 'metafor'. The studies have repeated measures (i.e multiple timepoints) and some of the studies have multiple exercise groups, some are the same cohort ...
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0answers
19 views

Correlation for Multiple Comparison within a study

We have: 2 treatment groups (A, B) 1 control group (C) sample size n is equal for all groups (A, B, C) correlation r_AB = 0 correlation r_CC = 1 ->The correlation of r_AC and r_BC is 0.5 ...
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0answers
36 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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1answer
485 views

What does the Hedges g mean in this meta-analysis?

I am looking at the outcome scores of the WOMAC for the three studies included in the meta analysis, but I am having a hard time figuring out what the data means in Table III. Could someone help me ...
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1answer
386 views

Calculating variance of one-sample cohen's d effect size

I'm trying to perform a meta-analysis where my effects are mainly one-sample t-test against chance level. I've easily found the one-sample cohen's d formula but I'm not able to find the variance ...
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2answers
20 views

Combined relative risk in meta study

I am looking at a meta study, and I've never done one (or looked at it much) before. From what I've learned about it so far, the way you calculate the compounded effect is by first calculating this $\...
2
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1answer
42 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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1answer
60 views

How to interpret the size of weighted mean difference (WMD) in a meta analysis?

I am studying Kishi T, Matsunaga S, Iwata N (2015) and they report that the weighted mean difference for the outcome "Total Time in Bed" is -20.16. Is there a rule of thumb to assess whether ...
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1answer
254 views

Meta-analysis of standard deviations

Does anybody know whether it's possible to conduct a meta-analysis, outcome of interest being difference in standard deviations between two medical interventions, instead of the difference in mean? ...
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1answer
39 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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0answers
41 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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1answer
541 views

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 ...
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0answers
27 views

What Heterogeneity/Between-Study Variance Estimator to use in a Reliability Meta-Analysis/Reliability Generalization Random Effects Model?

This is an extension of this question but for reliability generalization studies. Could anyone recommend a between-study variance / heterogeneity () estimator and method for computing confidence ...
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0answers
32 views

How to calculate aggregate standard deviation for composite scores in a meta-analysis

I wonder if someone would be kind and able to provide guidance/suggestions on a stats issue that myself and colleagues are trying to handle while performing a systematic review and meta-analysis. In ...
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1answer
39 views

"Mean pooled difference" or "pooled mean difference"?

Perhaps this is purely semantics but meta-analyses use these in interchangeably but which is more legitimate or are neither because there should be a hyphen? I would say pooled mean difference because ...
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1answer
28 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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1answer
44 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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0answers
13 views

Combined multiple within-group effect sizes

I'm conducting a meta-analysis on observational studies examined the association of age with different drug groups prescription and in order to combine the effect sizes of all drug groups together, a ...
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1answer
35 views

Metanalysis in R risk ratio compared to log risk ratio?

I have conducted a meta-analysis with the risk ratios and standard errors that have been provided to me. I cannot use the raw data. I was wondering if I should use the log of the risk ratio and the ...

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