Meta-analysis refers to methods focused on contrasting and combining results from different studies, in the hope of identifying patterns among study results, sources of disagreement among those results, or other interesting relationships that may come to light in the context of multiple studies.

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Meta-analysis of RR and OR calculated from 2x2 tables in R using metafor

Background My question concerns the calculation of risk ratios and odds ratios for meta-analysis using the metafor package. I know it looks long, but please bear ...
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38 views

Meta-analysis of prevalence at the country level

I'm working on a meta-analysis of prevalence data. The aim is to get estimates of prevalence at the country level. The main issue is that the disease is highly correlated with age, and the sample ages ...
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61 views

Why are small sample sized avoided in meta-analyses?

In most meta-analyses that I've read, the authors choose to exclude studies with really small sample sizes (e.g n=10). Why is that? Speculation I could speculate that one reason is that since the ...
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29 views

Combining outcome measures for meta-analysis

I have to conduct a meta-analysis. Following problem occured: a single study have measured Quality of Life and therefore, used two questionnaires. Now is my question whether I have two choose one of ...
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35 views

Stepwise meta-regression with R (metafor)

I am using the "metafor" package to do a multivariate meta-regression in "R". I have 6 predictors and I am able to run the full model (all the predictors simultaneously in the model) just fine. ...
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34 views

Bayesian meta-analysis

A colleague is conducting a Bayesian meta-analysis of some large-scale drug studies. Although she has experience with 'conventional' meta-analysis, she in new at the Bayesian approach. We have read ...
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58 views

Multivariate meta analysis and metaregression with multi arm randomized controlled studies

Please, i need to do a network meta-analysis and metaregression or a multivariate meta analysis and metaregression. I have multi arm randomized controlled studies. I tried the metafor package Dummy ...
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80 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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26 views

Meta-analysis Hazard Ratio

I need to explain the calculations involved in a meta-analysis with Hazard ratios (random effects) for programming in a tool. It is not possible to use statistical softtware neither webpages where ...
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42 views

Sample-adjusted meta-analytic deviancy macro/syntax for Excel, SPSS, MPLUS

I need to compute the sample-adjusted meta-analytic deviancy (SAMD) as part of an outlier search with meta-analytic data. Because we have a very large amount of meta-analytic data, computing this ...
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41 views

How to do multiple treatment meta-analysis?

I would like to compare 3 different treatments (no one treatment is considered the placebo, and these are not randomized control trials) from multiple studies in a meta-analysis. I am using the ...
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78 views

Meta-analysis of means and medians in R?

I've been asked to review the literature for all studies that estimate the mean and median Blood Lead Level (BLL) in a certain country, and then perform a meta-analysis to come up with one overall ...
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15 views

How to summarize mean +/- S.D. across disease severity

I am performing a meta-analysis and I have several papers that measure compound X in the blood of patients with a given disease. These papers have classified patients into groups based on disease ...
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23 views

One-way Anova Meta-analysis

I have a series of medical studies that I would like to summarize. Each paper measures a component in the blood (call it substance X) in patients with the same disease. Furthermore, each paper has ...
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78 views

Looking for beginner resources with effect sizes

First post here; first I would like to say that I have no background in stats whatsoever and not so much in math either (enriched high school math, and that's it). I started an MA and we have to do a ...
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12 views

How to assess heterogeneity between fitted, correlated parameter values?

I have four datasets, and for each one, I fit the same 3-parameter model. I'm interested in making a statement about the heterogeneity of each parameter value of the model, across the four datasets ...
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137 views

Multivariate meta-analysis in R: how to investigate network of variables

I would like to conduct a meta-analysis to investigate the interaction of three variables:hair color (dark/light), gender (male/female) and size (continuous). I have three studies reporting effect ...
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103 views

How to best analyze this data?

Im trying to figure out a way to analyze this data that I have: This is data that I pulled from various studies, and each study has a different sample size, and each study reported an obliteration ...
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53 views

Conducting IPD meta-analysis when studies use different measures

I'm interested in conducting an individual patient data (IPD) meta-analysis in which the main outcome of interest is a correlation coefficient between and IV and DV. The IV is measured slightly ...
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54 views

Is there any procedure to test the significance of meta-analytic estimate of correlation based on a set of sample-correlations?

Meta-analysis generates an estimate of an overall correlation. How could we examine that it is a valid estimate.
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68 views

Prevalence conversion to effect size in meta-analysis

I'm used to thinking about meta-analyses in terms of evaluating the impact of an IV on an outcome of interest (ex: relationship between a teacher's level of self-confidence and student outcomes), and ...
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129 views

Are the law of statistical regularity and inertia of large number applicable at level of meta- analysis? [closed]

Principles of sampling are applied on study of sample data on variables collected from number of observations(n) for estimation of population parameter(effect size). Meta analysis is applied on sample ...
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92 views

Testing main effects and interactions with rma from metafor

I'm not sure how to test for main effects and interaction effects between multiple moderator variables in metafor. Am I doing this right? My dataset is quite large, so we'll play with the iris ...
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21 views

Does measurement error include effects of moderator variables?

I am not very sure how to interpret measurement error correctly: as a constant, as a bias, or as a moderator factor? Is it presumed that measurement error includes moderator effects? Let it be in ...
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212 views

Combining information from multiple studies to estimate the mean and variance of normally distributed data - Bayesian vs meta-analytic approaches

I have reviewed a set of papers, each reporting the observed mean and SD of a measurement of $X$ in its respective sample of known size, $n$. I want to make the best possible guess about the likely ...
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1answer
121 views

Interaction effects in network meta-analysis (multiple treatment comparison) in R?

I would like to use network meta-analysis (or multiple treatment comparison) to investigate the main-effect and interaction of two factors on a continuous outcome variable. As an example the effect of ...
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84 views

Averaging multiple distributions

Suppose I have $X_1 \sim N(\mu_1,\sigma^2_1)$ and $X_2 \sim N(\mu_2,\sigma^2_2)$ (where the distribution is empirically estimated). I believe that $X_1$ and $X_2$ are actually drawn from the same ...
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28 views

What is the definition of covariance under the fixed-effects assumption for a meta-analysis of correlation?

There is a doubt about the meaning of covariance and its definition. Does it change under different conditions such as primary data or statistic such as r in case of meta-analysis?
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Use of different outputs in a meta-analysis?

I'm interested in performing a meta-analysis of instrumental variables analyses from a handful of different studies, asking for the same set of model results from all study investigators. However, at ...
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26 views

Is it always necessary to correct the sample correlations for a meta-analysis?

Some authors eg Hunter et al (1982) propose that we must correct sample correlations for the measurement error.It seems measurement error need not be corrected for when we take a recourse to the ...
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62 views

Is it appropriate to use a bootstrapped standard error in a meta-analysis?

If the effect size under analysis is too complex to allow for any other type of standard error estimate, is it appropriate to use bootstrapped standard errors to inform effect size weights?
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28 views

How to combine complete regression coefficients?

How I can combine hazards regression coefficient in meta analysis? I want to have a complete regression from combing hazard regression with different covariates. I mean some of them have additional ...
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76 views

Meta-analysis with a binary response variable

I am attempting to fit a model to my data for meta-analysis I'm working on. The response is binary (0 or 1), and I want to specify a binomial distribution with logit link function. The 2-3 (depending ...
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48 views

Expectation of correlated variables

I'm looking to compare effects $ \delta = \frac{\mu_T - \mu_C}{\sigma}$ for two studies, compared with the same control group. In order to find the covariance of effects for treatment A and treatment ...
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37 views

Can probability be used to calculate (any?) effect size measurement? Version 2

A similar question has been answered, but I reframed here to remove the ambiguity in that question as to what I'm after... (as a survival analysis was not performed) For example, some studies report ...
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29 views

Can probability be used to calculate (any?) effect size measurement?

For example, some studies report the probability of survival, on a scale of 0-1, with SE, and sample sizes for two treatments, rather than the mean and SD. Is there a sensible way to use the ...
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41 views

Is there a sensible way to calculate effect size from data reported in percentages?

Is there a sensible way to calculate effect size (ideally Hedges g* / Cohen's d or log response ratio) from data reported in percentages? An example of such data below. I would, for instance, be ...
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121 views

Statistical comparison of 2 independent Cohen's ds

Is it possible to statistically compare the Cohen's $d$ of two studies in order to determine of one of the two Cohen's $d$s is statistically significantly larger (or smaller) than the other one? I ...
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42 views

Meta analysis: comparing effects of two risk factors

I am conducting a systematic review to compare the effect of intervention A vs. B on outcome Y (A, B, Y binary variables). So far the collected studies are categorized as below: 7 studies on both ...
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78 views

How can I calculate the hazard ratio (HR) from one-sided $p$ values on stratified log-rank?

Recently, I have been preparing to perform a meta-analysis about the treatment of pancreatic cancer. When I extracted time to event (survival-type) data from the publications, I encountered some ...
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36 views

How to calculate the first principal component from multi-data sets (using WGCNA)

I have a bunch of datasets (gene expression profiles). From the datasets, I am gonna analyze co-expression profiles using WGCNA ...
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48 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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How to combine data from 5 surveys from the same population spanning 10 years

I have results from 5 surveys each 2 years apart and let us assume that no subjects are selected in more than one survey. The sampling method used in these surveys are biased and I have sampling ...
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65 views

Meta analysis of summary data or model of raw data?

I have data of the following form: Sample MeasureZZ Time Event S1 M1 t1 e1 .... I have calculated the influence of ZZ on survival by ...
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152 views

How can I combine data from 2 separate experiments?

I am a scientist and by no means a statistician. I have, I think, a very basic question for you all. I have performed the same experiment twice (analyzing levels of a certain protein) and am ...
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228 views

Main effects and interaction in multivariate meta-analysis (network meta-analysis) in R

I would like to conduct a multivariate meta-analysis (or network meta-analysis) to investigate the effect of two factors (A & B, 1 & 2). For every combination of the two factors I have a ...
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1answer
108 views

How to calculate effect sizes from mean and CI

I use escalc() function from metafor package to calculate various effect sizes or outcome measures (and the corresponding ...
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36 views

Estimating absolute difference between two conditions

A clinical trial examines the effect of two treatments upon lung function. Patients in each group contribute data at baseline and at the end of the trial. Baseline data are provided for each group ...
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148 views

How to estimate a standardized mean difference from two samples' quartiles?

I'd appreciate ideas about how to estimate the standardized mean difference (SMD) for two independent samples from each sample's size and middle three quartiles (i.e., median and 25th and 75th ...
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479 views

Minimum number of studies for meta-analysis?

Is there any reference or guideline regarding the minimum number of studies for conducting a meta-analysis?