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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Difference in proportion: Pre-post intervention-control study design

I am conducting a meta-analysis where I want to compare the proportion of samples pre- vs post- intervention. To do this, I have been calculating the difference in proportion (Post - Pre) as the ...
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36 views

Calculating average Spearman's Rho from Pearson r values (meta-anaylsis) [on hold]

What is the meta-analyzed coefficient, or mean Rho, of the following set of data. What type of estimate is this and what other information might you need for a more sophisticated procedure? Case ...
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46 views

Meta-analysis of percent relative to baseline in R using metafor package

I would like to conduct a meta-anaylsis in the context where I have studies available that measure a continuos variable at multiple time points (0, 1, 2, 3, 4, 5). Time 0 represents the baseline at ...
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20 views

meta-analysis, effect sizes for standard deviations

Is there any possibility to calculate effect sizes for the differences of standard deviations of two groups? (Is there any possibility to calculate the difference in the standard deviation between two ...
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11 views

Mixing ITT and TOT/LATE Effect Sizes in Meta-Analysis

I have a question concerning the coding of Effect Sizes for a large (educational) Meta Analysis with mostly latent outcome variables. Some studies provide "Intent to Treat" Data from which I ...
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10 views

Multiple groups - how to regularise estimate of level 1 parameters based on level 2

I am fitting some relatively complex structural equation models, but the specific model is not so important. I am estimating multigroup models, such that one parameter is completely free across ...
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1answer
19 views

Meta-analysis with studies reporting both positive and negative estimates

I'm organizing a meta-analysis on performances with studies showing sometime positive and sometime negative estimates. Sometime the result of the study is in a positive direction, with higher scores ...
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1answer
27 views

How do I translate logistic regression output into logged OR (and SE) for meta-analysis?

I'm attempting to conduct a meta-analysis using (logged) odds ratios, I'm using the Generic Inverse variance method (Review Manager) as some of my studies only report odds ratios and CIs (not raw ...
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1answer
32 views

Interaction effect of 2x2 ANOVA in meta-analysis

I want to meta-analyze the interaction effect of a 2x2 ANOVA. (I am not talking about an interaction in the meta-regression, as in this question but about an interaction as the focal effect that ...
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32 views

Meta-analyses for variance rather than means

What are the main complications / differences when conducting a meta-analyses where the metric of focus is not effect size (i.e., means) per se, but instead estimates of variances from models? Nods ...
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1answer
36 views

Calculating the correlation between difference scores from the correlations within timepoints

For a meta-analysis I am conducting, I need to know the correlation between two sets of difference scores. For example, imagine a study in which the researchers measure variables $x$ and $y$ at time ...
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1answer
162 views

independent replicate experiments yielding contrasting results

This is a though, simple experiment, for thinking efficiently about a real problem much more complicated... Imagine a simple experiment, trying to answer a simple question. For example, is body ...
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16 views

Meta analysis, joint posterior distribution of study effect

Meta analysis (with common study variation $\sigma$) often assumes that: $$ X_{i,j} | \theta_i \overset{ind}{\sim} N(\theta_i,\sigma)\\ \theta_i \overset{i.i.d.}{\sim} N(\mu,\tau) $$ where ...
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15 views

When is appropriate to combine two treatment groups from one study into a composite whole for a meta-analysis?

The treatment groups I would like to combine appear to be virtually the same, at least by generic label for each group, e.g., groups with the same treatment but implemented at different sites or ...
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29 views

Meta-analysis: design mixed-effects model in R

this is an example of my dataset: ...
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1answer
35 views

Meta analysis: transform forest graph output to percentage effect in R {metafor}

I need the forest graph expressed as % effect. I have run the model with the log ratio, and I know I could back-transform using transf=exp, which would plot the forest graphs expressed as the ratio ...
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21 views

Can Hedges' d be used to compare unlike effects?

I've got a question related to the use of Hedges' d in a meta-analysis of insect fitness information. Here is a link (pdf) to the paper I'm working with. In the appendices, the fitness information ...
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1answer
56 views

nonlinear meta-regression

Can someone point me to a basic explanation of theory and methods for fitting nonlinear curves (particularly quadratic functions) to meta-analytic data? I have a set of effect sizes that are clearly ...
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2answers
34 views

Using variance from a Jeffreys prior in a Prevalence meta-analysis

I am doing a meta-analysis on a group of studies, where the observation is a rate (no. of successes / no of trials). Some of the studies have small sample sizes (n<10) and/or did not observe any ...
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27 views

comparing two sets of meta-analysis

I have two subgroups (high / low BMI) on which several measures where recorded and analyzed on by various papers in a treatment and a control group. I was trying to verify if, for each measure, the ...
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36 views

Meta-analysis: Talking about power and inference (to power)

I need a little help or reassurance concerning how to explain power "to power", i.e. to decision makers that are not well versed in statistics. The problem is this: I have done three empirical ...
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1answer
93 views

Mixed-model meta-regression

I have a collection of continuous data from the literature, including the mean, the standard deviation and the number of observations for both experimental and control groups, as well some ...
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1answer
35 views

Metafor package: RMA and testing for interaction in two studies (Altman & Bland 2003)

I have traditionally used this simple test of interaction (http://www.bmj.com/content/326/7382/219) for comparing effect sizes between studies, and I would like to start performing it in R. Although I ...
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21 views

How big is the risk for regression in a single arm meta-analysis?

I'm performing a single arm meta-analysis of continous data deriving from efficacy evaluation of control gorups surgical procedure. How big is the risk for regression to the mean? And How it could ...
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90 views

How to deal with unequal sample sizes while fully embrace a dataset?

Imagine the situation: Mythical Seafolk use holes in the seabed as their burrows. Each hole has two parameters - diameter and depth. Majority of holes are unoccupied due to their surplus (n = 235). ...
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61 views

Effect sizes in within-subject design on R

I'm doing a meta-analysis but I need your precious help on couple things : 1) First, on R, in the compute.es package, I found only effect sizes computation formula ...
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90 views

Oddly large R squared values in meta regression (metafor)

I am using the metafor package in R. I have fit a random effects model with a continuous predictor as follows SIZE=rma(yi=Ds,sei=SE,data=VPPOOLed,mods=~SIZE) ...
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83 views

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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39 views

Independence of effects in meta-analysis and meta-regression

In meta-analysis, I know that an important assumption is independence. Clearly, if we want to estimate a pooled effect size, its best if each effect comes from an independent sample of observers. ...
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24 views

APA-style forest plot using metafor [duplicate]

I have produced a forest plot visualizing results of a meta-analysis, trying to meet the requirements according to the APA style, i.e., statistical terms to be italic, e.g., k = 10, or sub-scripted, ...
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1answer
57 views

computing mean and sd of d-prime from mean and sd of hits and false alarms

I'm working on a meta-analysis. Some studies report d', others report accuracy (hits and false alarms). I would like to transform all the data into the same measure, d' (also c). However, for many ...
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1answer
87 views

Metafor package: Interpreting rma model with two (or more) moderators.

New user of both stackexchange and R here. My questions are about mainly about interpretation, and my dataset is quite large, so I have not included my dataframe. I have two queries (in bold). Using ...
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49 views

Publication bias - trim and fill - macro/syntax

I'm looking for an SPSS or Excel macro/syntax that will allow me to compute Duval and Tweedie’s trim and fill procedure (see paper here: ...
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22 views

How to describe a distribution of statistics in a meta-analysis?

I'm conducting a meta-analysis using water-quality data collected from multiple lakes in multiple regions. Due to the differences in the sampling programs, each waterbody has been sampled an unequal ...
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72 views

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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26 views

Meta-analysis in R with multiple probes of a microarray

Regarding a question posted here, I have the same problem and I can't figure out a solution. I started by doing my meta-analysis in PLINK, but I want the confidence intervals of the meta-analysis, ...
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61 views

Is there an effect size for Kappa's?

I am staring a project on comparing standard ways of creating a classifier with some heuristic methods. The heuristic methods should result in a faster training for the classifier but should result in ...
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1answer
50 views

Combining two Odds ratios with the same control group

I am doing a meta-analysis of observational studies. As the disease I am working on has different stages, some of the studies reported ORs (95%CI) for each stage separately in comparison to a single ...
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2answers
216 views

Calculating effect sizes and standard errors for the difference between two standardized mean differences

I have two related questions, both of which are related to a meta-analysis I am performing where where the primary outcomes are expressed in terms of the standardized mean difference. My studies have ...
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1answer
494 views

Forest plot for meta-analysis displaying the mean ES with and without outliers

I am conducting a meta-analysis and am trying to produce a forest plot displaying the mean weighted effect size with and without the outliers. I looked on so many websites and tried a lot of syntaxes, ...
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169 views

Combining data from different sources

I want to combine data from different sources. Let's say I want to estimate a chemical property (e.g. a partitioning coefficient): I have some empirical data, varying due to measurement error around ...
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1answer
88 views

How to perform a meta regression with a random effect model?Which model should I use?How to start? (beginner)

I have to perform a meta-regression, using mixed or random effects model, but I don't have any software (except Matlab) and I'm new on this topic (having a relativelly poor statistics background). ...
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37 views

Meta-analysis with CMA

I wonder if I could ask you all a quick question regarding the input of effect size data into Comprehensive Meta-analysis(CMA)? I have tried contacting via the software portal with no response. I am ...
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1answer
73 views

Extracting data from bivariate vs multivariate analyses for the purposes of meta-analysis

I have what is a very basic question about meta-analysis. If data from individual studies about the relationship of interest are presented in both bivariate and multivariate analyses, which should I ...
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38 views

Does normal distribution assumption improve the quality of results of a meta-analysis of effect-sizes?

Different methods of meta-analysis have different assumptions and one of the popular assumption that has been invoked so often is that of normal distribution. can we work out meta-analytic results ...
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56 views

Meta-analysis of logistic regression

I would like to perform meta-analysis on studies that have a dichotomous outcome measure. I have the raw data for all studies I am including in my meta-analysis, so I can choose the best statistics to ...
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30 views

What to do with coefficients of log-transformed predictors in meta regression of effect sizes?

I am preparing data for a meta-analysis regression of effect sizes, in which I will study the determinants of effect size for a specific variable across several studies. I have some studies in my ...
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1answer
125 views

convert F-values to effect size

For a meta-analysis I'd like to calculate and aggregate ES-values from studies reporting F-values for mixed model-ANOVA-s. Can you recommend any literature specifically on this topic? +++ After ...
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26 views

If original data are available, should replication data be added and everything re-analysed (IPD) or is a meta-analysis better?

One common practice which increases the odds of obtaining spurious results is to keep collecting observations after a preliminary analyses are performed[1]. This occurs when the cutoff point for ...
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29 views

Moderator Sample Size Discrepancy in Meta Analysis

I'm coding a meta analysis and have come across a paper that seems to have significant variation in the number of participants who answered specific demographic questions. The total sample size is $N ...