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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1answer
35 views

Changing units of variance to match changed mean

I have a mean of hrs/day. I have converted this to mins/day (by multiplying by 60). However I am not sure what I should do with the SD or confidence intervals which refer to the variance of hrs/day. ...
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1answer
40 views

Network meta analysis without standard deviations

I am trying to compute Cohen's in some studies that I gathered in a Systematic Literature Review. Unfortunately, almost none of them report the standard deviation (nor df/t, or something for back-...
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0answers
88 views

Using metafor with multiple outcomes from single studies, and how to calculate within- and between-study heterogeneity?

I am currently conducting a meta-analysis where we have several studies that report multiple outcomes from the same participants. We've been advised to use the ...
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1answer
59 views

How can one get consistent (i.e. direct+indirect=total) effects in a Meta-Analytic SEM model with latent variables?

I have a mediation model with latent variables using datasets from a few studies. In particular, one of the latent variables is the outcome, while the others are tested as possible mediators of a ...
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0answers
103 views

Compute Becker's (1988) standardized mean change based only on difference score and t-statistic (meta-analysis)

In my meta-analysis, I'm combining independent-sample designs with single-group pretest-posttest designs. To ensure interpretability across designs, I would like to quantify the effects from pretest-...
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1answer
37 views

Assessing normality assumption of effect sizes in meta-regression

I'm considering options for estimating tau-squared (the true between-study variance) in meta-regression, and I know method-of-moments (MM), unrestricted maximum likelihood (ML) and restricted maximum ...
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0answers
30 views

Shouldn't we consider larger standard errors for effect measures or outcomes that are converted in meta-analysis?

There are methods to convert effect measures in meta-analysis (pdf). There are also methods to convert outcomes; at least, I am aware of the conversion described in Furukawa et al. (2005) from ...
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0answers
23 views

Meta-analysis of different binnings of the same continuous variable

I am conducting a meta-analysis in which household income is the IV. Unfortunately, for a variety of reasons, authors choose to operationalize income in a variety of ways. Some authors present ...
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1answer
72 views

Problem in accuracy when calculating p value from a 95% confidence interval

For my meta-analysis I have to obtain univariate analyses (HR, 95% CI, p value) from different studies. I came across one study with a given HR: 1.19 and 95% CI: 0.46 - 2.51. By surfing on the ...
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2answers
237 views

How to interpret heterogeneity in a meta analytic model

I try to fit a random effects model for my thesis, a meta analysis of studies about team planning and team performance. I'm using R and the package metafor to create z correlations and variance (yi, ...
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1answer
125 views

Odds ratio, Meta-analysis

I have the following for the data for the meta-analysis: OR , standard errors, logged OR , variance of logged OR I have generated a forest plots first using "OR" with "variance of logged OR" using ...
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0answers
42 views

Meta-analysis - effect size from multiple severity groups

I am currently performing a meta analysis to evaluate whether a measure (let's call it Meas) is correlated to the severity of a disease (Sev). The severity of the disease is reported as a score from 0 ...
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1answer
72 views

Can effect sizes (SES) be compared when the underlying null distributions are different in a meta-analysis?

Background: In community ecology one of the questions we are interested in is if the species in a community are non-randomly associated. To try and get at this we typically use a null modelling ...
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1answer
29 views

If someone wanted to do a meta analysis would they be able to use a publication that does not have p-values listed in the publication?

If someone wanted to do a meta analysis would they be able to use a publication that does not have p-values listed in the publication? Does a meta analysis really need a publication to have a p-value?...
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1answer
47 views

Type of studies reviewed in meta-analysis of proportion

What types of studies are reviewed for meta-analysis of proportions? For example can I included case-control studies and collect data of number of events from the total cases?
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1answer
65 views

proportional meta-analysis, small confidence intervals and I square of 100 %?

I am performing a meta-analysis of proportions, I have data about the number of cases and the total sample sizes. I will be using the Freeman-Tukey double arcsine (Freeman & Tukey, 1950; Miller, ...
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1answer
46 views

Potential bias of effect sizes due to ceiling (or floor) effects when weighting effect sizes by their variance for meta-analysis

Regarding meta-analysis, I am wondering whether there is a potential bias due to the ceiling effects (or floor effects) when weighting effect sizes by their sampling error variances. In case of ...
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1answer
56 views

Meta analysis: is there such a thing as too little heterogeneity?

First time I've seen results like these and they make me feel uneasy. Is it even appropriate to do a meta-analysis here? Even my poor forest and funnel plots are messed up. ...
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1answer
27 views

meta-analysis with correlation and se without sample size

I'm doing a meta-analysis on the regression slope. The comprehensive meta-analysis allows me to input either correlation and standard error, or correlation and sample size. But when I tried these two ...
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0answers
37 views

How can I conduct meta-analysis on longitudinal data?

Meta-analysis is a good way to synthesize data from multiple studies. Is it possible to conduct meta-analysis which contains a number of datasets, including longitudinal data (data was measured on the ...
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0answers
76 views

How do I calculate the confidence interval for tau2 in R, using the Paule-Mandel estimator and Q-Profile confidence intervals?

I am currently completing a meta-analysis of raw mean scores. I have used the R function metamean to complete this, and chose the Paule-Mandel estimator for tau-squared as I have a small number of ...
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1answer
741 views

How is weight of a study calculated/determined in a Forest Plot (e.g., by using metafor package in R)?

I was wondering how the weight of each study is determined in a Forest Plot? Here is a theoretical example of weights appearing in a Forest Plot using the metafor package. ...
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111 views

Meta-analysis using bootstrapped confidence intervals (non-normal data)

I have the results of two studies (my own and a previous study). I want to perform a small meta-analysis to obtain a better estimate of the effect size. For the two studies I have the means and 95% ...
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0answers
162 views

Meta-analysis of indirect effects/mediation models

I am writing up a manuscript with six studies (4 correlational, 2 experimental). All the studies test the same conceptual indirect effects/mediation model: I'd like to conduct a "mini meta-analysis" (...
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0answers
75 views

Why not use baseline standard deviations to standardize effect size in meta-analysis?

in my meta-analysis I have studies with three kinds of data reports of RCTs which I want to integrate into one group with standardized effect sizes. studies reporting baseline and post-treatment ...
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1answer
33 views

How to calculate Mean Sample-Based Reliability Estimates Used for Analyses

I am conducting a meta analysis of Pearson's r , of correlations presented between test scores and job performance ratings. I need to present an uncorrected effect size and an effect size corrected ...
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1answer
39 views

Average sample size of two fishers z correlations

I am conducting a meta analysis of Pearson's r correlations. As there are two correlations , sometimes three , for the same study and dependent variable I have averaged the correlations via fishers z ...
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1answer
78 views

Studentized Residuals in 'METAFOR' package: Meta Analysis with Mixed Effects

I am using the metafor package (documentation) to conduct meta analysis with mixed effects in R. I have noticed, however, that there are no studentized residuals available for the particular model ...
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2answers
96 views

Testing complex hypotheses involving glm/linear model coefficients

I have one independent variable (X) and three dependent variables (W, Y and Z). I am fitting a generalized linear model to each: $Y = g(\alpha X + \epsilon)$ $Z = g(\beta X + \epsilon)$ $W = g(\...
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0answers
44 views

Do I need to include interaction in the model when I am only interested in overall effect? [closed]

Say I am doing a linear model, with treatment and study effects, and I know the treatment effects are different across studies. I want to estimate the OVERALL treatment effect (NOT study-specific ...
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1answer
52 views

Averaging of two or more standard erros

I have calculated two standard errors for two fishers z correlations from the same study , both measuring the same variable. Is it acceptable for me to average the two standard errors into one? If so ,...
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1answer
136 views

Incorporate correlation between pre-post measurement into calculating SMD in R?

I have tried looking for this answer on every website, unfortunately without any luck. I hope you can help me out. I have calculated SMD in R(metafor package, escalc function) for a number of pre-...
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0answers
25 views

Calculating variance from standard error of pearsons r correlations z scores [duplicate]

I understand that to calculate the standard error of a pearsons r correlation converted to a z score you follow - 1 / (√N−3) But how do you calculate the variance from the standard error please? I ...
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0answers
48 views

Independent & non independent effect sizes/correlations for meta analysis

I am conducting a meta analysis of pearsons r correlations and would like to double check my understanding of independent and non- independent effect sizes/correlations. Am I correct in understanding ...
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1answer
361 views

How to calculate Inverse variance weight of several pearsons r correlations

I have a set of pearsons r effect sizes , converted to fishers z scores for meta analysis. I am wondering what data I need to calculate an inverse variance weight for each effect size and how I ...
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0answers
189 views

can you transform spearmans r into pearsons r for meta analysis

my meta analysis involves the calculation of overall effect size based on pearsons r correlations within studies. I am already converting the pearsons r to fishers z scores for analysis but I have a ...
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2answers
133 views

Aggregating coefficients in a meta-analysis

I have a question about the treatment of data in a meta-analysis. It is quite common in this particular field for researchers to essentially use data twice for analysis: once as a normal bivariate ...
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0answers
190 views

Adding weights to forest plot with subgroups

I am creating a forest plot with subgroups (roughly following this example). Now I want each subgroups to be weighted as if I would plot them individually in a separate forest plot, and the weights ...
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0answers
28 views

Multilevel meta analysis - how to set a uniform prior with boundaries

I am currently conducting a three-level meta-analysis and I would like to run the meta-analysis also by using a Bayesian approach. To run a meta-analysis I collected effect sizes that are correlation ...
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1answer
38 views

Evidence aggregation: combining estimates of a treatment variable from two regressions

I'm working on a paper, which partly replicates some findings from a previous paper in my field. To be more particular, I am running the same model, estimating the same treatment variable, using ...
2
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1answer
71 views

Test whether effect size in meta-analysis is significant when controlling for moderator

I am using the metafor package to conduct a meta-analysis. I’d like to test whether the overall effect size is significantly different from zero when controlling ...
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0answers
68 views

Is it possible to calculate an average correlation of r from several correlations of r? [duplicate]

Any help would be appreciated. I have a table presenting multiple r correlations between various formats of the same test and the construct/dimensions it purports to measure. Is there an acceptable ...
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0answers
94 views

Z-value in R using the Eggers test. How to get the t-value

I am currently conducting a meta-analysis using R for my masterthesis. To test for publication bias I ran the Eggers test. In the output I get a z-value, however in all the published meta-analysis ...
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0answers
103 views

Meta-analysis with binary variable and weighting with sample size - Is it possible?

I am trying to conduct a meta-analysis with my data on private equity performance versus the public stock market. The binary outcome is if private equity outperforms the public stock market (Yes = 1, ...
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1answer
106 views

Meta-analysis in R without control group? Purely improvement of symptoms

I’m currently trying to perform a meta-analysis in R via the metafor package using data that does not have a control group. In this case, I am looking to see ...
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1answer
350 views

Moderator Analysis in meta-analysis in metafor package - conceptual questions [closed]

I am a beginner in statistics and currently have to conduct a meta-analysis in my lab. I am facing some difficulties to understand the meta-regression. I read this webpage and tried to follow along: ...
3
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1answer
338 views

Three-Level Multilevel Meta-analysis: What exactly are the three levels? Multilevel vs. Multilevel SEM Approaches

Completely edited: If a meta-analysis include many studies that reported multiple effect sizes within each study, multi-level meta-analysis is one way to account for this dependency in effect sizes. ...
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1answer
34 views

Meta-analytic comparison of the variances of two groups

I have gathered data from a number of studies where two different groups have performed the same task. For each group in each study, I have number of observations as well as the mean and standard ...
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0answers
33 views

Is there a test error metric that takes into account variance of the data?

In standard machine learning applications, models are often evaluated based on metrics like RMSE or Deviance. I was wondering if there is a similar metric tailored towards meta-analyses that takes ...
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1answer
447 views

meta-analysis of linear regression coefficients

I have the summary results of a linear regression model with 26 covariates which has been fitted to two independent samples (with different sizes). Now I am planning to use the linear regression beta ...