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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Weighted correlation with uncertainty on both groups

I want to estimate the correlation between two studies, which studied the same variables in two different conditions. For each variable I have an estimate (b), standard error (se) and p-value (p). ...
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Meta-analyzing incidence (count) data with many zero cells

I am conducting a meta-analysis on the incidence of a rare event. I have 15 single-arm studies with events occurring in only 2 studies. The metarate function in the meta package allows for meta-...
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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 ...
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Converting unstandardised regression coefficients to Cohen's d for meta-analysis

I am conducting a meta-analysis of Cohen's d and some raw effect sizes are unstandardised regression coefficients. Of these unstandardised regression coefficients: Some are based on a binary ...
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990 views

Interpretation when converting correlation of continuous data to Cohen's d

A popular textbook on meta-analysis (1) discusses how to convert a correlation, $r$, to Cohen's $d$ (i.e., the standardized mean difference): I became confused about how to interpret the resulting $d$...
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15 views

Test for Subgroup Difference Compared to Test for Moderator

I have performed a proportional meta-analysis to evaluate the rate of procedural success for two medical procedures. The two procedures comprise the two subgroups in my meta-analysis (FNA and FNB). I ...
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Interpreting effects in a meta analysis random intercepts regression model

I have a random intercepts model with two different clustering levels: studies and countries within which these studies were made. So, my interest is to estimate a model to figure out the grand mean ...
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Outlier Detection in Meta-Analysis Models for Observational Studies of Adverse Drug Outcomes using Distributed Networks

I hope you are in good health. My thesis is on outlier detection in meta-analysis models. I will be using a case study from Canadian Network for Observational Drug Effects Studies (CNODES) to detect ...
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Why is my standard error for the treatment effect is not giving the right 95% confidence interval in R (meta package)?

I am trying to do a meta-analysis using risk ratio, lower and upper 95% confidence interval in meta package in R but for example, M study, obtained upper and lower 95%CI ([0.7162; 1.1690]) were ...
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162 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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What method for analysis of pooled data (continuous variable) [closed]

I sought to perform meta analysis of continuous variables I have extracted mean and SD from multiple studies for a variable What is the statistical method to compute a "global" mean + SD ...
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Is Meta Analysis the Future of Bayesian Statistics?

Is Meta Analysis the Future of Bayesian Statistics? To summarize these two concepts: Bayesian Statistics involve using historical information about the distribution of model parameters to supplement ...
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Meta-analysis in R with multiple SNPs

I'm conducting a meta-analysis on two genome wide association studies (GWAS), each consisting of 150 SNPs, for which I computed summary statistics for association. I'm using the R package meta and the ...
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Predicted treatment effect for causally related conditions

Let's say there are two medical conditions $A$ and $B$ that are causally-related, i.e. that they share a common etiological process $C$. For example, $A$ and $B$ could be related autoimmune conditions ...
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1answer
38 views

What to do with missing effect sizes in meta-analyses?

I'm currently working on a meta-analysis but I'm unsure what to do with missing effect sizes. Effect sizes in my dataset may be missing for two reasons: The effect size is non-significant and the ...
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How to conduct a meta-analysis on ICCs (i.e., test-retest reliability)?

I have calculated two-way single consistency ICCs in R using the irr package. There are multiple ICCs representing test-retest reliability across these time points. Is there a way to compute a meta-...
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Pooling in a Meta Analysis

I am looking to pool data for adverse events for a meta analysis and I wanted to see if my plan made sense I want to pool my AE together based on the Clavien Dindo categorizations, as this will make ...
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Adding Cumulative Means and Variances

I would like to get cumulative data about opioid use after surgery on day 2 of use. I have the mean, SD for day 1 and for day 2. My understanding for the means is I can add them together. When it ...
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1answer
21 views

"Media" as a measure of central tendency

I've just read a meta-analysis that used 'media' as a measure of central tendency: "The media of skin side events related to PPE was 75.13%". I've never come across the use of "media&...
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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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2answers
278 views

hazard ratio: are they normally distributed?

I am looking at forest plots (in the context of meta-analyses of clinical trials). I see values for hazard ratios, together with 95% confidence interval. My question: to compute this confidence ...
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Combine group studies and case-studies in the same meta-analysis?

I heard from colleagues that case studies and group studies are typically not grouped together in the same meta-analysis. Several papers discuss the topic of which type of studies are "combinable" (e....
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1answer
414 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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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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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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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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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
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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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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
80 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
28 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
257 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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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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165 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 ...
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2answers
102 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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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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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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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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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
25 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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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
54 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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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
37 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
971 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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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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