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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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metafor meta-analysis for pre-post differences without a control group [on hold]

I am conducting a meta-analysis of the effectiveness of a pain medication. The studies I included do not have a control group. I am used the following commands but by reading others comments I ...
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Adjusting weights in meta-analyses using R

I am conducting a meta-analysis in R. Some of my studies provide more than one effect size for the same sample. I would like to account for this by adjusting the weight that each within-study effect ...
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18 views

How to adjust continuous and categorical variables for categorical variable?

I am performing a metaanalysis where I am trying to find predictors for an ordinal response variable. Additionally, I want to perform pair-wise correlations on some of the variables. I have a ...
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25 views

meta-regression using metafor

How should I syntax the rma function from metafor package in order to get results in the following example? My objective is to compare values (means) among species. I have different papers ...
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Meta-analysis pooling an n-of-one study with a (slightly) larger study - can/should it be done?

I'm performing meta-analyses of a continuous measure based on clinical studies. For one subgroup of interest, there are only two studies available: one with n=5 patients and one with n=1 patient. ...
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16 views

Homogeneity test in survival meta-analysis with adjusted HR

I was wondering what was the way to measure heterogeneity in a survival meta-analysis. I have for each study, an hazard ratio calculated with a penalized cox model (...
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1answer
49 views

Calculating effect size for a study with no groups

I am working on a meta analyisis of the effects of e-learning in an organizational context. I have prepared a list of about 25 studies to analyze and I have organized all the path coefficients based ...
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22 views

Meta-analysis for case control studies

I am working on a method of meta-analysis for case-control studies by stratifying cases and controls then calculating the effect size. Can I do a meta-analysis including only case-control studies for ...
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18 views

Meta-analyzing means/SDs from repeated-measures studies

I'm working on a meta analysis of prospective studies assessing changes to mental health in the year following an event. For the purposes of example, say it's the severity of depressive symptoms (...
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1answer
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Meta-analyzing rates of change in one variable observed in one group over time

I'm working on a meta analysis of prospective studies assessing changes to mental health in the year following an event. For the purposes of example, say it's the prevalence of major depressive ...
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1answer
22 views

Standarizing coefficients from unstandardized coef. without Standard Deviations

In the meta-analysis I am including standardized regression coefficients (b). Sometimes, I have not b, and I calculated it from the B (nonstandard regression coefficients)x [(mean Standard Deviation -...
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30 views

Standard error for difference between two independent gains

I've calculated an effect size for the difference between two standardized pre-post differences of two independent groups of subjects. That is: $[Mean_{dif_{group~1}}/SD_{dif_{group~1}}]-[Mean_{dif_{...
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How can I convert difference-in-differences to an effect size? [closed]

I haven't been able to find a good source on a way to convert the difference in differences to Cohen's D. The way I've been calculating the DD is: ...
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2answers
175 views

Causes of bimodal distributions when bootstrapping a meta-analysis model

I help a colleague to bootstrap a meta-analysis mixed-effects model using the metafor R package framework authored by @Wolfgang. Interestingly and worryingly, for one of the model's coefficients I ...
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1answer
25 views

In a meta-analysis, do you report the full N of each study or just the experimental n?

I just noticed that one meta-analysis (Jeon & Day, 2016) reported only the size of the experimental group. For example, when I look at the particular N sizes for the Robb & Kano (2013) studies,...
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50 views

R package for meta-analysis of beta-distributed data

I am conducting a meta-analysis, and my effect sizes are proportions, with a credible interval for weighing. I think I should assume a beta-distribution, but I do not know which package to use. This ...
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variance of Cohen's d effect size for two “dependent” samples [duplicate]

The derivation of the sampling variance of Cohen's $d$ effect size for the case of two independent samples is well established (see HERE). However, my question is what is the sampling variance of ...
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Hardy Weinberg Equilibrium And Outliers-How to deal with them?

I am carrying out a meta-analysis and meta-regression to study the association of a gene with a complex disorder. I have carrie
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1answer
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Coding nested factors for 3-level in rma.mv function of metafor package

I'm working collaboratively on an arm-based, network meta-analysis in the agricultural sciences. After carefully reviewing the Konstantopoulos walkthrough and Viechtbauer's slides to develop the code, ...
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Regularization techniques (ridge, lasso or elastic-net regression) for meta-analysis

I was perusing the StatQuest YouTube channel, and serendipitously listened to a series of videos on regularization techniques (ridge, lasso or elastic-net regression). It came to my mind that such ...
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1answer
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Use of nested random terms in meta-analysis with a moderator

I am conducting a meta-analysis and I am struggling with the random structure when there is a continuous moderator and a nested random term. Starting with a simple example: ...
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Interpretation of two odds ratios derived from two different cohen's ds, comparability for meta-analysis?

I have a question regarding the conversion of cohen's d into odds ratio (OR) and the comparability of results from two different situations. I wonder if the ORs derived from the two situations can ...
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9 views

For a meta-analysis study, is it correct to derive specific haplotypes from multiple studies that report varying number of SNPs at a gene locus?

My question is based on conducting a meta-analysis on the association of multiple variants in a single gene with a complex disorder using published case-control studies. For my study, around 5 well-...
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1answer
29 views

Difference between N case studies and case series with N patients

Is there any reason to treat data from multiple case studies differently from data from a case series that reports data on multiple patients? Assuming the case-series intervention was the same for ...
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1answer
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Questions about standard error

We are trying to create a table of standardised effects and standardised errors to compute for a meta-analysis. And I had a few questions around this Can you get a standard error for pearson ...
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Meta-analysis with response ratios and log transformed variables

I thought I would ask you something on the computation of Response ratios (Yt/Yc) and what to do when variables are already logged for instance income variables. If you have the answer that would be ...
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Comparing meta-analyses with partially overlapping controls

I would like to compare to meta-analyses that have semi-overlapping controls. In this situation, a single meta-analysis cannot be performed. There are known methods for comparing metas of ...
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Multivariate meta-analysis without individual patient data

Here is what I have. I have the results of 20 studies ($i=1,\dots,20$). For each study $i$, I have 6 outcomes $y_{ij}$ ($j=1,\dots,6$) and the within-variance of outcome $j$ in study $i$ $\sigma_{ij}^...
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Averaging Meta-Analytic Correlations?

I am conducting meta-analytic SEM and interested in looking at one outcome. A previous meta I was going to use as part of my data reports meta-analytic correlations for this outcome, however it is ...
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23 views

Coding of cross-over study's effects in a meta-analysis

One of the studies to be included in my meta-analysis has a cross-over design: between T1 and T2, a first group does the treatment condition while a second group does the control condition; and vice-...
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1answer
23 views

COMPARISONS OF ODDS RATIOS

For example, if I have 3 different trials each for 3 different drugs and I used meta analysis (sub group analysis) to generate effect sizes. How can I interpret the effect sizes? All drugs are being ...
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1answer
22 views

INDIRECT COMPARISONS BETWEEN MULTIPLE DRUGS [closed]

So I have conducted a project involving 5 different drugs. There are no head to head trials between them. Only trials comparing these drugs to placebo. I have tried to pick trials where the patient ...
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1answer
33 views

INDIRECT COMPARISONS

I am conducting a project where I comparing a 5 different drugs (anti-psychotics) for a particular treatment group. There are currently no head-to-head trials for me to be able to make direct ...
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how to compare two interventions when one treatment improves an outcome while other worsens it

I need help with meta-analysis Description- we have two types of medical treatments- A & B across multiple trials. I'm trying to calculate cumulative odds ratio of an adverse event happening ...
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1answer
49 views

Heterogeneity test in meta-analysis

In a random effect meta-analysis model with one categorical independent variable $\theta_{ij}=\theta_i+s_j+\epsilon_j$, where $\theta_{ij}$ is the observed effect size in category $i$ in study $j$, $\...
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1answer
29 views

Comparing Meta-Analysis of identical studies

I'm doing an extracurricular programme at my university as part of which we have to write a review article. My supervisor agreed to a meta-analysis. I want to investigate whether the preprocessing of ...
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17 views

Can we perform meta-analysis of successive but independent studies?

I measured a variable $X$ and estimated the error bars on my measurement with the objective of testing if $X$ is significantly different from zero. I concluded that $X$ is different from zero only at ...
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Meta analysis: Pooling hazard ratios of continuous vs. dichotomous parameters?

I have a question regarding pooling hazard ratios derived through different means for a meta-analysis. Software: RevMan 5; Method: generic inverse variance (log hazard ratios). My issue is that some ...
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What does the decomposition of a relative risk look like?

Say I have a relative risk of smokers that smoked 1-20 cigarettes per day. What is the mathematical identity between that RR, the RR of those that smoked 1-10 cig/day, and RR of those that smoked 11-...
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28 views

How can you meta-analyse continuous and binary repeated measures outcome data?

Context: the random effects meta-analysis is of studies that measure visits to the doctor (visits), as a continuous variable (by reporting mean visits and respective standard deviations) or as a ...
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3answers
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can I work out *the* standard deviation from a value given as “+/- 1 standard deviation”

I'm confronted by a table of values: 17.1 (16.6) 18.0 (9.5) 38.1 (22.5) 30.6 (16.7) In the left-hand column we have some mean values. I’m told that the values ...
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1answer
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Network meta-analysis of correlation coefficients: a logical paradox?

A colleague of mine wishes to conduct a network meta-analysis of correlation coefficients for a set of imaging tests (eg ultrasound, computed tomography, magnetic resonance imaging, and so forth). ...
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2answers
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PRISMA Statement: number of records returned by (one/several) databases?

In keeping with the guidelines of the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) Statement, I am trying to fill in their flowchart (Fig. 1) with the details of the ...
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Combine group studies and case-studies in the same meta-analysis?

I heard from colleagues that case studies and group studies are typically not grouped together in the same meta-analysis. Several papers discuss the topic of which type of studies are "combinable" (e....
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Heterogeneity in meta-analysis studies: pooling across, vs separate analyses

The therapeutic intervention whose effect I need to meta-analyse has several regional variants, that amount to small-to-medium differences in how the therapy is administered to patients. Now, there ...
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IPD meta-analysis: need to weight regression and population level estimates?

Using individual patient data (IPD) from various studies, do I need to weight observations in a meta-analysis? Each study used a two-stage cluster sampling design with uniform samples per cluster and ...
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3answers
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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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Meta analysis of multiple IV-regressions

For simplicity let us consider a single output Y and a single endogenous regressor of interest S. Suppose we have run multiple experiments over different periods in time, where we in each experiment, ...
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1answer
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Idiosyncratic features of studies to be meta-analysed

I am working on a meta-analysis to assess the effect of a given speech therapy. Most papers (primary studies) use endpoints/outcomes that are standard for the intervention under scrutiny (speech ...
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Running a Multilevel Linear (Mixed-Effects) Meta-Analysis Model without a variance-covariance matrix

I have a dataset that I want to run a meta-analysis on. However, the data has a hierarchical structure with several endpoints per study and where studies are further clustered together. So, I should ...