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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Meta analysis across studies with multiple response measures

I'm trying to do a meta analysis across a bunch of bird playback studies. Thanks to help on a previous post here I'm fairly certain I need to use inverse variance weighting (maybe with the 'meta' ...
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Meta-analysis of trials given hazard ratios

I'm trying to do a meta-analysis in R (using metafor) of trials where the outcomes are hazard ratios and I'm given the 95% CI for them and/or the standard error and n. So if I have columns like: <...
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Discrepancy between metafor and weighted lm() standard errors

My friend and I are trying to understand why a weighted lm() v. a fixed-effect rma model from the ...
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1answer
2k views

Is stratified meta-analysis more or less objective than meta-regression?

Reviewer asked me why I use meta-regression as a way how to deal with heterogeneity among effect sizes instead of conducting stratified meta-analysis. I tried to google "stratified meta-analysis" and ...
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329 views

Whether to apply structural equation modelling separately to each of a set of heterogeneous correlation matrices in a meta-analysis context?

I'm in the process of performing an Structural Equation Modelling (SEM) meta-analysis on some psychological data. Ultimately I want to examine a mediational model based on a set of correlation ...
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1answer
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Presenting results of a meta-analysis with multiple moderators?

I wish to present the results of my meta-analysis using the best practices possible. I do not find, however, examples in articles similar to what my output is. Here's a simplification of my model and ...
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783 views

Step-wise Bayesian updating as a prior selection strategy

There is a famous principle in Bayesian that says: 'Yesterday’s posterior is today’s prior'. Lindley (2000). Now, suppose there are three studies conducted chronologically. Based on Lindley's (2000) ...
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279 views

What are the reasonable properties of p-value combination methods when all p-values are the same?

Suppose we are testing a null hypothesis $H_0$, by combining evidence from $n$ independent tests, using a p-value combination method $M$. The combined p-value is $M(p_1,...,p_n)$. Assume the extreme ...
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381 views

Choosing the scope when performing multiple comparisons?

On both a practical and philosophical level, how should you choose the scope when performing multiple comparisons? When a study performs 10 tests to check the hypothesis that 10 explanatory variable ...
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Meta analysis of Multiple regression

I have 10 predictor variables and one outcome variable. However, I used three scales to measure the outcome variable. I conducted three separate regression analysis, with one of the three different ...
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234 views

Which binomial confidence interval 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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Practical data collection tips for performing a network meta analysis (mixed treatment comparisons)

As described previously in this post, I am currently working through issues with conducting a network meta analysis (also known as mixed treatment comparisons). For those unfamiliar with this method, ...
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How to conduct a meta-analysis using raw data?

I think meta-analyses are a great way of exploring a hypothesis when available evidence is heterogeneous. Usually however when conducting a meta-analysis one puts aggregated data in a model, possibly ...
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1answer
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Difference between Meta-Analysis, Meta-Regression and Moderator-Analysis

What is the difference between the classic meta-analysis (that aggregates effect sizes from a sample of studies to a summary effect size), meta-regression analysis and moderator analysis? As I ...
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592 views

Two studies, opposite results: Am I allowed to compute an overall mean using random-effect model?

I am performing a meta-analysis. I have a subgroup made only of 2 studies and they show opposite results. The 1st has excellent outcomes the 2nd very bad ones. Is it true that I am not allowed to ...
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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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Is it possible to do meta analysis of only two studies

Is it possible to do meta analysis of only two studies. What will be limitation of such analysis.
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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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1answer
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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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2answers
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How to do meta-regression in SPSS?

I am trying to manage a meta-regression in SPSS17 using the effect size as the dependent variable. I want to explore if my independent variables affects the effect size. Some small practical questions:...
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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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Subgroups in meta-analysis

I am reviewing a dissertation that does a meta-analysis of studies looking at a certain behaviour in rodents. The author analysed ~20 studies and did a meta-analysis. They then split those studies ...
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1answer
139 views

Using p-values reported as inequalities such as $p<0.05$ in meta-analysis; can I convert them to $0.05$?

I am currently undertaking a meta-analysis of the expression profile of specific biomarkers in a specific disease. During the extraction process, I extracted the name of the biomarkers and their ...
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984 views

Estimate an overall correlation from the correlations within subgroups

Assume that you are working with variables $x$ and $y$ divided into groups two groups, $g_1$ and $g_2$. You know the following information: The number of people within groups $g_1$ and $g_2$, ...
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Converting Adjusted Odds Ratios to its RR counterpart

I am doing a meta-analysis of studies which reported their estimates sometimes as OR and sometimes as RR. I wanted to convert the OR to RR, so that I can pool them together. I know that I can use this ...
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1answer
246 views

Testing for publication bias in meta-analysis when effect is raw mean

I am conducting a multi-level meta-analysis using rma.mv in the metafor package in R. The effect size measure I am working with is the raw mean (...
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How can I compute a log odds ratio for a within-subject design that could be meta-analyzed with log odds ratios from between-subject designs?

Background and Problem I have a question concerning a meta-analysis combining effects from between- and within-subject designs using log-odds ratios (OR) as the metric of interest. I am familiar with ...
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Computing Paired Samples (pre/post) Effect Size with Limited Information

I'm conducting a meta-analysis using the Hedge's g effect size statistic. Many of the studies are only reporting: pre-treatment mean score pre-treatment standard deviation post-treatment mean score ...
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1answer
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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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Meta-analysis and homogeneity -- what did these guys do?

I appreciate any insight into this meta-analysis. This is a meta-analysis on alogliptin efficacy and safety. In the 2nd paragraph of the discussion that make this statement: Although heterogeneity ...
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Meta-analysis of proportions

I am conducting a meta-analysis on 20 studies. The outcome of interest in each study is represented by a proportion/percentage. The sample size n is known and is different for each study. I have ...
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1answer
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Sampling variance for meta-analysis one-sample data

I want to run a meta-analysis over several studies reporting one-sample data (e.g. comparing participants' scores against a baseline score of zero). I calculated Cohen's d by dividing the difference ...
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Comparing relative risks of independent samples

I would be really grateful for help with the following. I have two independent studies looking at treatment A on disease B. Both give RRs of disease B according to treatment exposure for different ...
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1answer
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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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920 views

Combined odds ratio

I wonder if there's a way to calculate the combined odds ratio for certain SNPs in a meta-analysis of a several GWAS, even when you don't have the SE, neither beta, for each individual study? Thank ...
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104 views

Why report test statistics in a publication?

Some style guides instruct authors to report not only the results of a hypothesis test, but also the value of the test statistic from which it was calculated. For example, APA Style suggests t(...
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1answer
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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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When is this effect size for chi-squared appropriate?

A paper I am reviewing contains the following measure of effect size for chi-squared $r = \sqrt{\frac{\chi^2_{obs}}{df+2}}$ where $\chi^2_{obs}$ is observed chi-squared and $df$ is its associated ...
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646 views

What methods can be used to specify priors from data?

Background I am generally interested in learning appropriate methods of using data to specify priors. A previous question asks how to elicit priors from experts and received some good recommendations....
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Variance of Cohen's $d$ for within subjects designs

Based on this paper by Lakens 2013, I understand there are two recommended ways for calculating Cohen's $d$ for within subjects measures.  Cohen's $d_{rm}$ (which assumes the correlation between ...
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467 views

Independent replication experiments yielding contrasting results; how to combine them?

Imagine a simple experiment, trying to answer a simple question. For example, is body temperature the same in men and in women ? To answer this question, let's say you sample 10 men, and 10 women, ...
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2answers
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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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2answers
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Random Effects for Mantel Haenszel

I'm familiar with the standard Mantel Haenszel method for Odds ratios and Risk ratios. Is there also a random effects method? If so, can anyone provide the formulae and/or citations?
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How to extract data from published articles (RCTs) to do a meta-analysis?

I am doing a meta analysis for the first time and have a few basic questions regarding statistical analysis. Let's say I have one study where the primary outcome (thrombosis) in the 2 treatment ...
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1answer
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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994 views

Power of Meta Regression

Why it is said that Meta Regression analyses have low power? & How to calculate the same?
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1answer
676 views

What kind of cut-offs are used for publication bias tests in meta-analysis?

I have performed meta-analysis and included four different tests for publication bias in the analysis - classic fail-safe N, Orwin's fail-safe N, Duval and Tweedie's trim and fill as well as funnel ...
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4answers
3k 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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1answer
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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
575 views

Post hoc analysis after meta regression

I am running a meta-analysis using metafor R package. I am comparing studies on a continuous variable, that can be synthetized by the mean. Such studies can be grouped in three blocks. I used a meta ...

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