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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11 views

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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1answer
15 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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1answer
450 views

Meta-analysis: How can I compute the sampling variance of Fisher's z-transformed correlation coefficients for within-subject designs?

Rosenthal and colleagues (Rosenthal, Rosnow & Rubin, 2000) suggest that it is possible to compute r (correlation coefficient) as an effect size from repeated measures designs (e.g., by converting ...
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1answer
166 views

Calculate sample variances from linear regression model for meta analysis?

I want to perform a meta analysis in two levels using linear regression in R (with lm() ). I understand that in the second level I should perform a weighted ...
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38 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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0answers
15 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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15 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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1answer
383 views

Do I really need correlation coefficients when computing effect sizes from pretest-posttest studies?

I am computing effect sizes from various studies for a meta-analysis. Most of those studies follow a typical pretest-posttest design (repeated measures), thus I compute the effect size as a "...
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1answer
49 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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15 views

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
44 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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4answers
115 views

How to combine multiple dose levels in a study for meta-analysis

I am conducting a meta-analysis of RCTs for treatment A vs. control. Some of the studies have multiple dose levels of A. Should I combine these groups with different doses of A and compute one effect ...
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16 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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1answer
123 views

Binomial confidence intervals - which is correct?

Background: I am working with a data set that requires a transformation. It's prevalence data so I have proportions to deal with, and as the proportions are quite low, I'm using the Freeman-Tukey ...
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1answer
308 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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0answers
27 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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0answers
18 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
29 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
29 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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14 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
21 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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1answer
686 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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2answers
178 views

Is it standard practice to omit studies lacking an estimate of sample standard deviation from meta-analysis?

It appears common among meta-analyses to omit studies that do not provide an estimate of sample standard deviation. For example, a previous question reviews some ways to estimate $\sigma$ from ...
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30 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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37 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
28 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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2answers
2k views

In a meta-analysis, how should one handle non-significant studies containing no raw data?

Let's say that I'm conducting a meta-analysis, looking at the performance of group A and group B with respect to a certain construct. Now, some of the studies that I'll come across will report that no ...
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0answers
11 views

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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1answer
52 views

Meta-analysis for two-group comparisons cannot include studies where both groups have only one data?

I have collected papers reporting no. of observed species in two types of habitats, A and A’, and been trying some outcome measures for meta-analysis. I noticed that effect size such as Hedges’ g ...
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1answer
823 views

Performing subgroup analysis using the metafor package

When I performed a subgroup analysis on a catergorical moderator named "moda" (with two levels:m and n) in my data, ...
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0answers
24 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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2answers
849 views

Regression Bounded Between -1 and 1

I am performing a meta-analysis on the response of rodent abundance to clear-cut logging. I have data from multiple sites, across multiple years, and for different species of rodents, and am using ...
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0answers
1k views

Meta-analysis with mean and sample size but without standard deviation?

I'm doing meta-analysis for a treatment done in seeds. I have approximately 130 series with value of the control mean (Xc), its treated homologous mean (Xe) for crop yield and the number of ...
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3answers
3k views

Why does finding small effects in large studies indicate publication bias?

Several methodological papers (e.g. Egger et al 1997a, 1997b) discuss publication bias as revealed by meta-analyses, using funnel plots such as the one below. The 1997b paper goes on to say that "...
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1answer
117 views

Approximating OR with RRR in meta-analysis

Similarly as in this question, I'm working with meta-analysis of studies reporting ORs of an event. I have one study where I'm not sure if it should be excluded. The frequencies of the outcome are: ...
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1answer
23 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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0answers
9 views

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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2answers
64 views

Data Extraction when hazard ratio is shown by Log-transformed independent variable

How can we know the hazard ratio per unit of the independent variable when the data are gine by log2 change (or double increase) in the independent variable? For instance, for each double increase ...
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0answers
10 views

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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0answers
25 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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1answer
68 views

Chi-Square test for homogeneity – Comparison between Sub-Samples

I am conducting a meta-analysis and calculate the following chi-square statistics to test for homogeneity in the data. After forming two sub-samples - say, sub-sample A has a X² of 2,500 (df: 40) and ...
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0answers
33 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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2answers
227 views

Meta Analysis: Pooling samples or determine an average effect size

I am new to meta analysis and how I understood the terminology is that there are actually two ways of performing a meta analysis. Let's consider 5 clinical studies with fixed effects. Fixed effects in ...
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46 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
126 views

Meta analysis of continuous outcome but different follow up time

I am looking at different studies and the outcome is a percent reduction from baseline. The studies all have different follow up times. If I simply control for follow up time, that may be biased since ...
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1answer
27 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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1answer
138 views

Meta-analysis in R without control group? Purely improvement of symptoms

I’m currently trying to perform a meta-analysis in R via the metafor package using data that does not have a control group. In this case, I am looking to see ...
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1answer
347 views

Effect size calculation for Kruskal-Wallis mean rank test

I have a published paper in which I'm attempting to calculate the effect sizes for various outcomes. For a pre-post scale, the authors report the sample size, mean rank, and p-value for an outcome (...
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0answers
28 views

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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39 views

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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