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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21 views

Adding mean change values as data inputs on Revman for a meta-analysis

I am currently conducting a meta-analysis using Cochrane's Revman software. Very briefly, I am interested to find out whether an eHealth intervention was effective in improving health outcomes (e.g., ...
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Do we need fixed effects in Neural Networks?

I have a background in econometrics, and generally when we are working with panel data (i.e. there's a time-series as well as a cross-sectional dimension), we would include fixed or random effects. ...
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Combining coefficients of two independent linear regression

I have two datasets. Dataset 1 has $P$ measurements of dependent variable $Y$ and independent variable $X_1,,,X_N$. Dataset 2 has $Q$ measurements of dependent variable $Z$ and $X_1,,,X_N$. $Y$ and $Z$...
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Log-transforming a mean - what to do with SD?

I am doing a meta-analysis of means. I have gathered means, SD and N from a set of studies. I do not have access to the raw data of the means. After doing an Anderson-Darling test, I found that the ...
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1answer
30 views

Fisher's method for combining p-values

I'm using the sumlog function in the metap package of R, and have a few questions about the nuts-and-bolts of this function: 1)Some of my p-values are reported as '<0.001'. How do I include these?...
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51 views

How to calculate pooled mean difference?

I'm currently doing a simple pooled analysis study; which, unlike meta-analysis, does not involve weighing between studies. However, my outcome of interest involves continuous outcome (pre-...
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How to interpret meta-regression results with significant moderators but no significant overall effect?

I'm conducting a meta-analysis where I have a given set of studies, each with multiple effects (correlations in my case) I'm interested in. Each correlation coefficient answers a different research ...
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23 views

Meta-analyzing Likehood ratio or wald test outputs

Hope your day is going well! I've been reading a lot on the Wald test and likelihood ratio test recently because it is the output of my RNA sequencing data. I was interested in meta-analysis of ...
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65 views

Meta-analysis of standardized regression coefficient (beta coefficient)

I am trying to do a meta analysis on the effect of smoking with hypertension. Some of the studies used 'beta coefficient' and its confidence interval as the effect of smoke exposure with increase in ...
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26 views

Converting probit coefficients into effect sizes for meta-analysis

I am conducting a meta-analysis but the raw study coefficients are probit coefficients. I am planning to convert these to log odds to meta-analyse through the formula: 1.61 * probit_coefficient. Q1) ...
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26 views

Comparing effect sizes across multiple groups within meta analysis

I have multiple studies on a particular effect, each study tracks certain other criteria, and each has a control group. The units of measurement in each study are not always convertible between each ...
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Meta-analysis with incomplete data

I'm doing a meta-analysis comparing infection rates in 2 sub-types of liver operations (say Big surgery Vs Small surgery). I have a few studies which compare the 2 but other studies that only report ...
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1answer
58 views

Meta-analysis with only p-values

I am doing a systematic review on the risk factors that predict infection after liver and pancreatic surgery. These risk factors include parameters like age, sex, smoking, pre-operative chemo etc. I ...
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1answer
83 views

Choice of box size and weights for a forest plot from random effects meta-analysis

I am doing a random-effects meta-analysis where the variable is measured in standardized mean differences. The actual measures vary, but are related to drug use in rats and control vs. treatment. I ...
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23 views

Compute standardized mean difference and its standard error from regression-adjusted mean and 95% CI for 2 groups

I am working on a meta-analysis (using aggregated data), where the outcome is a continuous variable. One study reported post-treatment outcome values as regression-adjusted mean and 95% CI in each of ...
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30 views

Calculate correlation between different effect sizes retrieved from individual studies in meta-analysis

I am working on a meta-analysis where i have two different effect sizes for each study (2 variables A and B that are measured after a specific treatment). I can run two different meta-analysis on ...
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26 views

Generic inverse variance meta-analysis with metagen function, how to report results?

I have recently performed a pairwise meta-analysis where I pooled the effect estimates and variances of different studies that either reported mean differences and odds ratio for the two arms using ...
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1answer
32 views

Combining effect sizes to learn about the difference between two groups?

I am interesting in learning if there is difference between the control and the treatment group in a paper I am reading. Unfortunately the paper only compares the respective conditions to a 0 effect ...
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1answer
30 views

Meta Analysis with Likelihood Ratios

I am currently writing a protocol for a systematic review and meta analysis to analyze the available evidence regarding epidemiologic studies on risk factors for pneumonia. The end goal of the ...
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19 views

How to find standard error or standard deviation of the percent difference between two prevalence values?

I am having trouble working out how to find the standard error or standard deviation for a column that contains the percentage points difference for two prevalence values. I have general practice ...
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1answer
23 views

How does pooling affect variance?

Suppose you are looking at the prevalence of a certain disease and you can detect this disease in fecal samples. How does having a bunch of pooled fecal samples (i.e., taking a fecal sample from 5 ...
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66 views

Meta-Analysis without a Control Group

I am conducting a systematic review and meta-analysis which is investigating health-related quality of life in a particular patient population. I am having difficulties with conducting the meta-...
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38 views

Why is my meta analysis OR and 95% CI less precise than my study results? [closed]

I am trying to perform a simple weighted average meta analysis of 2 odds ratios from 2 studies (I will be adding more studies when I get the results). However, when I meta analyse using the METAFOR ...
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1answer
38 views

Should we do a meta-analysis of non-inferiority trials?

Since non-inferiority trials are designed meticulously to achieve an effect size demonstrating no significant difference between treatments, so there may be certain essential differences in design of ...
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Transforming reported effects at sample means for a meta-analysis

I'm doing a meta-analysis about tax avoidance (like this: https://poseidon01.ssrn.com/delivery.php?ID=...
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31 views

How to Calculate Observed Variance in a Random-Effects Meta-Analysis

I've received a revise and resubmit on a meta-analysis investigating the effects of a positive psychology intervention on depression and anxiety symptoms. I used Hedges' g as the effect size with a ...
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1answer
24 views

Data fusion for multiple correlated t-tests

Question is similar to this unanswered question. I have several data sets each corresponding to a different location. Every row of each dataset contains a measurement of the same quantity taken at a ...
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How do I test whether the distribution of effect sizes are different across intervention types?

I've extracted 3,456 Cohen's d effect sizes from published studies, and categorized each based on intervention type (four different intervention types). I did this to understand the distribution of ...
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Possible NAs in Beslow estimation with repeated data?

I would like to seek your advice on a problem I encountered recently. I bootstrap on a test that includes a Breslow estimate for survival data. Since these are meta-analyzes, I am bootstrapping on ...
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29 views

How to bootstrap a statistic calculed in a meta-analyis?

I have calculated a statistic in a meta-analysis of individual data and I want to bootstrap it to obtain the variance (no analytic expression is available) to make a test. First, I was naively ...
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35 views

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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52 views

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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1answer
41 views

'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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45 views

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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1answer
60 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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1answer
36 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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24 views

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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28 views

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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26 views

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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1answer
43 views

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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1answer
29 views

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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1answer
440 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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1answer
43 views

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
29 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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35 views

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
49 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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20 views

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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60 views

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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