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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Effect size and standard error for Mann-Whitney U statistic
I'm conducting a meta-analysis and one of the studies only reports Mann-Whitney $U$ statistic. The table with results is pasted below.
Circled in red is the $U$ statistic that tests the differences ...
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Does Bayesian statistics make meta-analysis obsolete?
I'm just wondering if Bayesian statistics would be applied consequently from the first study to the last if this makes a meta-analysis obsolete.
For example, let's assume 20 studies which have been ...
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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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1
answer
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Combine 2 groups based on the regression coefficient
I have two groups of people, N=211 in group 1, N= 310 in group 2.
I would like to combine these groups because they share a certain characteristic that I am interested in. The groups are used in a ...
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Meta-analysis with zeros for mean and sd
When I do a meta-analysis with RevMan 5.3, mean and sd for group A is zero and zero, and mean and sd for group B is 47 and 2. The result is "not estimable". How to solve the problem?
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Meta analysis using the effect size based on mean and multiple outcomes [duplicate]
I have few questions on the meta analysis.
First, the data is longitudinal and according to the CMA (comprehensive meta analysis) guidebook
"Working with more than two outcomes per study
The formulas ...
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Meta-analysis: How can I combine effect sizes from studies with between- and within-subject designs?
I am planning a meta-analysis. I read some books (e.g., Cumming, 2012) and papers (e.g., Johnson & Eagly, 2000). I learned that standardized measure of effect size like d and r are sensitive 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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Methods of Meta Analysis
I have question on the methods of performing meta analysis.
I have data that consists of multiple Randomized Control Trials (RCT) with different dose levels and observational studies with different ...
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How to reduce subjectivity in the Baseline Inequality Index for meta-analysis
I have recently come across an interesting means to appraise baseline differences in competing groups in clinical trials being pooled for meta-analysis: the Baseline Inequality Index.
As far as I am ...
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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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Combining Estimates from Conditional Quantile Regression : Meta-analysis?
Suppose i have several studies (e.g 5) and i use conditional quantile regression (e.g using the package quantreg in R) to obtain conditional quantile estimates at ...
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Pooling data across experiments- correlation
My question is basically about a procedure introduced in a statistical web-site (http://labstats.net/articles/combining_experiments.html), which is about combining data from multiple studies. In this ...
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Can we apply propensity scores or the Miettinen multivariate confounder score to meta-regression?
Meta-regression is an established approach to adjust at the study-level the results of a systematic review and meta-analysis not encompassing patient-level data. It basically consists on a regression ...
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How could one derive power indicators for omnibus tests?
A while ago I posted a question regarding performing post-hoc power analyses in meta-analyses and was given a couple of useful links to discussions regarding why this isn’t a good idea. From my ...
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Meta-Analysis using RVE (robumeta)
I'm runnig a meta-analysis, correcting for clustering of standard errors with the robumeta command. R gives the following warning:
If df < 4, do not trust ...
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answer
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Testing association in meta analysis
I am doing a meta-analysis where I have the baseline and 2 months post-intervention measurement of a continuous variable (say a) for two groups (control and intervention). I also have measurements for ...
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Which is the best book to learn meta-analysis?
I have somewhat extensive experience in meta-analysis, but remain an avid reader on this topic.
I am thus wondering, which is the best book to learn meta-analysis in general?
And which books are the ...
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Is it valid to do confirmatory factor analysis on correlation coefficients derived from a meta-analysis?
I have just read a paper in which the authors performed a meta-analysis to extract correlation coefficients (specifically between five personality variables and emotional intelligence). They then used ...
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Can I calculate the number of patients in experimental and control group based on HR?
I would like to conduct the meta-analysis of randomized clinical trials. In some of them in the subgrup analysis the number of patients in experimental group (Ne) and control group (Nc) are not given, ...
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Is it uninformative to present power in meta-analyses after the fact?
In Borenstein et al's (2009) Introduction to meta-analysis, page 263, one can read the following:
A power analysis should be performed when the review is being planned, and not after the review has ...
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How to conduct meta-regression with continuous and categorial variables?
I am conducting a meta-analysis in psychotherapy research and want to use meta-regression to identify moderators.
The regression outcome is a correlation between a psychotherapy process variable + ...
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Effect Sizes: use the variance or the standard error?
I have calculated the variance of the Log Effect Size (Ln Response Ratio RR) following the Hegdes et al., 1999 equation:
$$
\frac{(SD_E)^2}{n_E\bar{X}^2_E} + \frac{(SD_C)^2}{n_C\bar{X}^2_C}
$$
And ...
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Multilevel Structural Equation Model - Meta analysis - STATA gsem [closed]
I am quite familiar with mixed effects (multilevel models) in meta analyses.
Now, I want to do a mixed effects (multilevel) meta analysis structural equation model (MASEM) with STATA and the gsem ...
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How to combine groups to create a single pair-wise comparison in meta-analysis?
for example, study report smokers as current, smoker, a former smoker, and occasional smoker, how can we combine smokers with occasional smokers to create one group.
Cochrane has given method but it ...
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Meta-analysis with both observational studies and randomized trials
I am starting to work on a meta-analysis project and I have received the data.
The data includes both randomized trial and observational studies.
Is there any article, book, or website that explains ...
3
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1
answer
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How to aggregate evaluation metrics from many evaluations?
Say I'm developing an automatic term extractor and I have a lot of documents. Let's assume this documents do not all have the same size. I also have a list of terms that should be extracted from each ...
4
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How to deal with unexpected low heterogeneity in meta-analysis?
I am performing a meta-analysis in R with metafor package. Primary studies report the reduction of plant species to certain amount of nitrogen fertilization. Effect ...
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answer
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Quality ratings in meta-analysis
I hope you can help.
I've been told by my supervisor that I should not use quality ratings on my studies prior to analysis; and instead explore quality of ratings post analysis to explain groupings/...
4
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1
answer
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metafor package and bootstrapping
I have issue combining metafor and boot package.
My original meta-analysis model is following and this runs well:
...
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Can a meta-analysis of studies which are all "not statistically signficant" lead to a "significant" conclusion?
A meta-analysis includes a bunch of studies, all of which reported a P value greater than 0.05. Is it possible for the overall meta-analysis to report a P value less than 0.05? Under what ...
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Meta-analysis: significant heterogeneity vs. significant between-study variance
I am running a simple random-effects meta-analysis in R using the metafor package, with random intercepts at the study level:
...
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Is there a frequentist approach to Lu & Ades network meta-analysis model?
I'm currently reading the seminal Lu & Ades network meta-analysis paper. It proposes a bayesian hierachical model for dichotomous outcomes which treats each study's arm as an (conditionally) ...
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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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1
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Reversing the reference category
I am doing a meta-analysis. How can I change the reference category such as in a pooled analysis?
Most studies have reported male as the reference group (Female : Male). However in one study the ...
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2
answers
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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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1
answer
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Interpretation results of multivariate meta-analysis model
I would like to ask if you can help me in interpreting the results of my analysis or if perhaps you know a paper or a book where this is nicely explained. I am conducting an analysis in order to check ...
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Meta-analysis with zero values for mean difference and s.d
For a meta-analysis, means and s.d. for the experimental and control groups were required to calculate the mean difference (MD or yi) and variance (vi) of each study with the escalc function of ...
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1
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multilevel metanalysis with two outcomes
I'm investigating the effect of an evaluative learning paradigm that uses the self on implicit and explicit attitude change and identification. This includes only studies we've conducted in our lab ...
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Model with the intercept fixed at 1: selection with 'glmulti'
I am performing the following model selection in R using 'glmulti' (based on aicc values):
...
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1
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Interaction in meta-regression model selection
I am a student who is performing a meta-analysis and want to select the best regression model (in terms of AICc values) that explain what are the explanatory variables that can explain better the ...
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A meta-regression with effect sizes from variously designed studies
I am performing a meta-regression using various types of effect size from two independent samples design study; pre- and post-test for one sample design study; and frequency comparison design study ...
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Theoretical foundations of meta-analysis
I am hoping someone can give me some guidance (or references) relating to the mean and variance of the distribution of the mean of sample means.
I am thinking about a large number of populations, ...
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Is it possible to calculate a log-odds ratio with repeated trials?
Background and Problem
This is a continuation of a question posted earlier (here) in which I describe a meta-analysis combining between- and within-subject designs using log-odds ratios (OR) as the ...
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answer
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Can I combine binary and continuous data to meta-analyze prospective changes over time?
I'm interested in conducting a meta-analysis of mental health in the first year after an event. I have a set of prospective studies that assess mental health at baseline (i.e., immediately after the ...
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Publication bias: Egger's Test significant depending on subset. Why doesTrim and Fill not add studies?
For my final thesis I performed a meta-analysis with different subsets (subgroup analysis). Although I systematically searched the literature (I was brutally sophisticated), depending which subset I ...
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Clarification of output of metabin and metareg
I used the metabin and metareg commands in the meta package of R.
There were 21 trials and I initially looked at the safety outcome. The output of metabin is below.
...
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Averaging regression output
I have multiple logistic model outputs with the same predictors. The dependent response is very similar changing slightly randomly.
I would like to take an average of the coefficients of all models. ...
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Show two Kaplan-Meier Estimates at time t are statistically different
I'm doing a replication of a study. My main concern is that the study I'm replicating is overestimating the risk of disease progression in higher risk patients who receive contemporary treatment. The ...
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Extract data for bayesian meta analysis of survival data
I want to do a meta-analysis of survival data using a bayesian framework (gemtc). In the package documentation the input needed are the responders and the exposure in person-time for each arm of a ...