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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Why is my confidence interval for sigma so large in my three-level meta-analysis of means?

I recently ran a three-level meta-analysis of means in R, and the confidence interval for the sigma values in the main analysis and in the moderator analyses are very wide. I am wondering why this may ...
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When conducting a moderation test in a meta-analysis, should you include a category including only 1 study?

I am conducting a moderation test as part of a meta-analysis and the moderator variable is categorical. One of the levels in the categorical moderator comprises only one study (though there are ...
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Meta-regression analysis of the correlation between dependent variables

I have a set of studies which report a biomarker and an incidence of an outcome at baseline and at end of follow-up. I would like to get a measure of how much the change in the biomarker(chg_bm) ...
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2answers
65 views

Estimation of standard error of the median from median and confidence intervals for meta-analysis?

I have a dataset of median survival time and their confidence intervals. One way of pooling these medians using meta-analysis requires an estimate of the standard error of the median / variance of the ...
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25 views

Network meta-analysis with trials of different follow-up time [closed]

0 I am trying to do a network meta-analysis, and calculating anticipated absolute differences, I have seen other papers generating anticipated absolute differences for treatment for x number of years. ...
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1answer
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Ecological Covariate for a meta-analysis on reading and bilingual learners

Is it possible to do a meta-analyses on reading intervention studies of bilingual students and include ecological covariates for the analyses? I think I am a bit confused as what exactly is an example ...
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9 views

formally comparing model fit indices from two correlation matrices

I have a model that I would like to validate. I do not have raw data but am working only through correlation matrices. Is there a way to compare model performance and fit in a statistically formal ...
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A priori power analysis for response ratios (not odds ratios) in meta-analysis

I am doing a meta-analysis and my data is in the format of response ratios (bioconcentration factor = concentration in a plant/ concentration in the soil). The r functions I found for power ...
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1answer
23 views

Best tool to appraise the internal validity of a systematic review or meta-analysis

We are conducting an evidence base synthesis for a major European cardiovascular assocation. We plan to search, appraise and summarize systematic reviews and meta-analyses on our topic of choice, ...
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P-curve analysis for meta-analysis of diagnostic accuracy study

I tried to do a meta-analysis of diagnostic accuracy study. I found out that I have a publication bias based on the Deek's regression test. Thus, I want to supplement my analysis with P-curve analysis ...
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2answers
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Adding a variable's effect (from literature) to an estimated Cox model

I have a Cox model (estimated with coxph), built using "some" variables. There is an extra variable that I have not measured, so it is not in my dataset, but I do know the effect of that ...
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29 views

Model selection for Multivariate random effects models in metafor

I am currently in the process of trying to run a multivariate meta-analysis model in metafor with random effects. I have no previous experience working with meta-analysis models and have read many ...
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Could a nomogram be built from meta-regression coefficients?

I'm trying to build a nomogram from meta-regression co-efficients. The meta-regression model is done using the metafor package. However, I would like to represent the results into a nomogram. The RMS ...
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Power in meta-analysis: Determining the number of studies to reach a specific confidence interval width

Aim: I would like to do a prospective power-analysis (before data collection) to determine the number of studies that have to be included in my meta-analysis. Data Format: Heavy-metal concentration in ...
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24 views

Is it possible to conduct meta-analysis for interaction between two continuous variables

all. I have conducted four studies to examine an 2-way interaction predicting a continuous outcome variable from a continuous independent variables and a continuous moderator. So everything is ...
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1answer
34 views

How can I calculate variance of log Odds Ratio if Odds Ratio extracted from the study is pre-calculated?

I want to conduct a meta-analysis using odds ratio as my metric. The studies I am using provided pre-calculated odds ratios only, along with their confidence intervals and/or standard error. I need ...
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21 views

What is the type A uncertainty from a DerSimonian Laird estimator?

When averaging independent results, the type A uncertainty can be estimated as the standard error of the mean, $$\frac{\sigma}{\sqrt{n}}$$ where $\sigma$ and $n$ are the standard deviation and the ...
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1answer
27 views

Wha are $R^2$ values not available in fixed effects meta regressions

I'm currently conducting a meta-regression for my moderators from a meta-analysis my team recently conducted. In calculating the fixed effects meta-regressions, my objective is to identify how much ...
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1answer
27 views

Combining Forest Plots in One Plot [closed]

I am trying to combine 4 forest plots into 1 matrix type plot output with 2 columns and 2 rows. I have tried grid.arrange multiple times but I continue to get "only grobs allowed in list." ...
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34 views

Meta-analysis effect size conversion: regression coefficient to correlation coefficient (r)

I am trying to extract data from an article for a meta-analysis. I would like to convert the following information into a correlation coefficient (r): Pre-covid period: Nov 19 2019 - March 2 2020 (...
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1answer
40 views

metafor: correlational output from multivariate meta-analysis question

I have a quick question about the metafor package. I have been using the author's guide for stochastically dependent effect sizes (via github) to run a [multivariate meta-analysis][1] using multiple ...
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1answer
53 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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27 views

Calculating a variance term for AUC using data points extracted from a figure

I am currently performing a meta-analysis where I am pooling area under the curve values. For some papers I only have access to the figure. For example: Using WebPlotDigitizer I can extract the mean ...
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21 views

Stratified Intercept in Individual Patient Data Metanalysis in R

I am trying to run an Individual Patient Metanalysis (IPD) in R. However, using a Random Intercept Model seems not to be appropriate since I only use 4 Trials. In this article a stratified study ...
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1answer
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Compare pre-post change intervention across studies

I have got a question regarding the comparison of the effect size comparing a new (digital) intervention with previous data using a traditional intervention. In summary, we've designed a new (digital -...
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25 views

Meta analysis of standardised mean differences

I just had a couple questions regarding meta analysing normal random variables that are from different but comparable questionnaire scores. I have read that when you have a situation like this it is ...
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Interpreting negative difference in mean?

I'm currently doing a meta-analysis, looking at risk factors for the development of a disease. Most of my data has been converted to odds ratios, which I have no difficulty interpreting. However, in ...
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25 views

Meta-analysis of time-to-event data for single group design

I would like to perform a meta-analysis of time-to-event data for a single group (i.e. there is no comparison group). How do I do so, what are the statistics required? I understand that for 2-group ...
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1answer
27 views

Overall treatment effect from a mixed model in metafor

This is in continuation of my previous post (Testing the effect of moderators in metafor package) Thanks@Wolfgang for the clarification. Now I used model: A<-rma.mv(yi, vi, mods = ~ factor(soil)+...
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1answer
32 views

How to convert F and t-values to standardized Z scores?

What is a good reference for converting F, t, and eta-squared values into standardized z scores for a meta-analysis? A psychology oriented textbook/reference would be great! Thank you.
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How does tau squared (between-study variance) differ for network meta-analysis versus pairwise meta-analysis?

I'm currently trying to replicate a random effects network meta-analysis in Excel. When estimating between-study heterogeneity, I can calculate Cochran's Q just fine via: $$Q=\sum w_i(y_i-\hat\theta)^...
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26 views

Meta Analysis of Change From Baseline (Missing the final standard deviation)

I am currently doing a meta-analysis and some of my studies only include the baseline standard deviation and the change from baseline standard deviation. EDIT 2 The Cochrane handbook for meta-analyses ...
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21 views

Is combining Odds Ratios with Relative Risk in a Meta-Analysis Possible?

Can I combine ORs and RRs using generic inverse variance if the the event rare? There appears to be simple methods for converting ORs into RRs so would I do the conversion first and then apply the ...
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1answer
24 views

Meta analysing outcomes with different definitions?

I'm looking at meta analysing a set of studies that report adverse events and was wondering if it makes sense to synthesise these outcomes if they measure the same adverse event defined in different ...
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2answers
32 views

Convert correlation r to Cohen's d (unequal groups of known size)

I am doing a meta-analysis. I would like to estimate Cohen's d for various studies. The correlation is made up of (a) a binary variable and (b) a numeric variable. I also know (a) the mean for the ...
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44 views

In a multi-level meta-analysis, are moderator variables random or fixed effects?

I am conducting a multi-level, mixed-effects meta-analysis where effect sizes are clustered within studies. In the R package metafor, I specify my model like this: <...
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15 views

Effect Sizes in Machine Learning Models

I am working on designing a systematic review & meta-analysis of machine learning techniques in the field of stuttering. One issue that has arisen is that: the currency papers usually trade in ...
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1answer
46 views

How to calculate effect size for a pretest-posttest-control design study?

I am trying to calculate the effect size of exercise on depression. So I have 2 groups (control and intervention) in an RCT setting. I have both mean values and standard deviation of groups at T0 (...
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41 views

Combining dichotomous and continuous outcomes in a meta analysis

I have data on weight gain from a set of studies that is both continuous and binomial. The continuous data is the mean weight at the end of the trial of the two trial arms and the binomial data is the ...
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3answers
107 views

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
23 views

Does it make sense to fit a nested model if some nested factors only have one level?

I am trying to build a meta-analytic model (using metafor package in R) to analyze effect sizes extracted from multiple studies (I have about 300 effect sizes from ...
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9 views

Aggregating results from multiple unsupervised clustering studies

Is there a framework, similar to meta-analysis, to interpret or aggregate the results from multiple unsupervised clustering studies? For example, take two studies on evaluating patients with heart ...
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19 views

How to fit Frequentist meta-analysis for regression between endpoints?

General Information I have $j = 1, \dots J$ studies which report two measurements, $x_{obs, j}$ and $y_{obs, j}$, and their standard errors, $\sigma_x$ and $\sigma_y$. Both measurements are assumed to ...
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0answers
34 views

Do estimates of effect size vary as a function of sample size?

Imagine 50 studies of the same phenomenon with 100 participants, vs. 50 studies with 200 participants. Would we expect greater variation in estimates of effect size with a smaller number of ...
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1answer
47 views

Pooling different effect sizes in meta-analysis with metafor

Simple question here. Suppose that I have 20 papers to be included in a meta-analysis, which compare the risk of death with 2 treatments, A vs. B. For 15 of them, I only have number of events and ...
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0answers
17 views

Metanalysis in R for writing interventions

I do a metanalysis (the subject is writing interventions for students with Learning Disabilities) in R package. Due to the use of continuous variables, the effect size I used was the Standardized Mean ...
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0answers
28 views

Multi-level meta-anlaysis

I'm conducting a meta-analysis in which some of studies reported multiple effect size as they examined the outcome on multiple groups of glucose-lowering drugs. So, a three-level meta-analysis was ...
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Can I compare two other correlation coefficients in one meta-analysis?

I am in the process of initial research into the relationship between blood pressure and the PPG signal parameter. I have two groups of articles that describe: 1) the correlation coefficient between ...
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1answer
15 views

Meta analysis of control groups

I am conducting systematic review to establish control value of a new diagnostic variable (continuous data). I would like to do sub-group analysis as well. Since it is only for control group, is meta-...
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Is it possible to perform a meta-analysis on the SEE generated from models?

Let's say you were interested in performing a meta-analysis on the predictive validity of various simple linear regression models which differed in the method of extrapolation. One of the main metrics ...

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