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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12
votes
2answers
6k views

How to parameterize the ratio of two normally distributed variables, or the inverse of one?

Problem: I am parameterizing distributions for use as a priors and data in a Bayesian meta-analysis. The data are provided in the literature as summary statistics, almost exclusively assumed to be ...
8
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1answer
2k views

Multilevel multivariate meta-regression

Background: I'd like to conduct a meta-regression using studies which have (1) several outcomes/constructs (= multivariate) and (2) multiple effect sizes for every of these outcomes because of ...
8
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1answer
6k views

How to conduct a meta-analysis on studies that report results variously as odds ratios, hazards ratios, or rate ratios?

I'm doing a meta-analysis of some studies that report results variously as odds ratios, hazards ratios or rate ratios (all with confidence intervals). Is there any way to combine these together/...
29
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3answers
3k views

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 ...
17
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2answers
12k views

Multiple imputation for outcome variables

I've got a dataset on agricultural trials. My response variable is a response ratio: log(treatment/control). I'm interested in what mediates the difference, so I'm running RE meta-regressions (...
7
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1answer
2k views

How to choose between fixed-effects and random-effects model in meta-analysis?

In meta-analysis packages, both fixed effects and random effects models are available. How do one choose between these two models? Since one is assessing different studies, should one not choose ...
5
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1answer
731 views

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 ...
5
votes
4answers
2k views

Meta-analysis of means and medians in R?

I've been asked to review the literature for all studies that estimate the mean and median Blood Lead Level (BLL) in a certain country, and then perform a meta-analysis to come up with one overall ...
11
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3answers
3k views

Are these formulas for transforming P, LSD, MSD, HSD, CI, to SE as an exact or inflated/conservative estimate of $\hat{\sigma}$ correct?

Background I am conducting a meta-analysis that includes previously published data. Often, differences between treatments are reported with P-values, least significant differences (LSD), and other ...
15
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4answers
1k views

Looking for good introductory treatment of meta-analysis

A (non-statistician) colleague has been encountering meta-analyses in papers he reviews for medical journals and is looking for a good introductory level treatment so he can educate himself. Any ...
2
votes
1answer
226 views

computing heterogeneity assigned to random factors in meta-analysis

I want to calculate the proportion of total variance in a multi-level meta-analysis with 2+ random effect terms according to pp. 1261 & equation (24) in Nakagawa & Santos 2012 https://www....
4
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2answers
1k views

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 ...
5
votes
1answer
1k views

Main effects and interaction in multivariate meta-analysis (network meta-analysis) in R

I would like to conduct a multivariate meta-analysis (or network meta-analysis) to investigate the effect of two factors (A & B, 1 & 2). For every combination of the two factors I have a ...
4
votes
2answers
3k views

How to combine data from 5 surveys from the same population spanning 10 years

I have results from 5 surveys each 2 years apart and let us assume that no subjects are selected in more than one survey. The sampling method used in these surveys are biased and I have sampling ...
3
votes
1answer
222 views

Meta-Analyzing Dependent Effect Sizes (Log Response Ratios)--Is Averaging Effects An Acceptable Solution?

Given k studies, for each computing a log response ratio $L$ and variance $v$ following the Hegdes et al., 1999 equations: $$L = ln(R) = ln(\bar{X}_{E})- ln(\bar{X}_{C})$$ $$v = \frac{(SD_{E})^2}{n_{...
6
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2answers
2k views

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 ...
4
votes
1answer
4k views

Averaging multiple distributions

Suppose I have $X_1 \sim N(\mu_1,\sigma^2_1)$ and $X_2 \sim N(\mu_2,\sigma^2_2)$ (where the distribution is empirically estimated). I believe that $X_1$ and $X_2$ are actually drawn from the same ...
18
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2answers
11k views

Quality assurance and quality control (QA/QC) guidelines for a database

Background I am overseeing the input of data from primary literature into a database. The data entry process is error prone, particularly because users must interpret experimental design, extract ...
7
votes
1answer
11k views

Converting odds ratios to Cohen's d for meta analysis

I'm conducting a meta-analysis largely on mean differences data, however I have several articles that report only an odds ratio, N, p value, and confidence interval, and I need to convert this ...
3
votes
1answer
899 views

Meta-analysis: is there a way of including dependent effect sizes without averaging across them

I'm running a meta-analysis with a binary outcome (succeed/fail). I am primarily interested on the effect of predictors related to the study (e.g. age of participants, type of task) on the binary ...
10
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2answers
1k views

Justifications for a fixed-effects vs random-effects model in meta-analysis

I have read several publications attempting to justify the use of a fixed effects model with statements along the lines of "the fixed-effects model was chosen because the heterogeneity was low". ...
6
votes
2answers
1k views

How to conduct a meta-analysis using raw data?

I think meta-analyses are a great way of exploring a hypothesis when available evidence is heterogeneous. Usually however when conducting a meta-analysis one puts aggregated data in a model, possibly ...
4
votes
1answer
727 views

R software implementation of combining mixed treatment comparisons and meta-regression

I am currently conducting a meta-analysis in which I need to use a mixed treatment comparison method. As I understand it, this method works in the following way: Say you have a group of studies that ...
3
votes
1answer
5k views

Standard error from OR and HR

I'm planning to combine several observational studies, some of which have produced odds ratios and some hazard ratios. How do I get the standard error from the odds ratio $1.57$ ($95\%$ CI: $1.08-2.27$...
9
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2answers
490 views

How to best handle subscores in a meta-analysis?

I am conducting a meta-analysis of effect sizes d in R using the metafor package. d represents differences in memory scores between patients and healthy. However some studies report only subscores of ...
5
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3answers
513 views

What methods can be used to specify priors from data?

Background I am generally interested in learning appropriate methods of using data to specify priors. A previous question asks how to elicit priors from experts and received some good recommendations....
4
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2answers
287 views

Looking for beginner resources with effect sizes

First post here; first I would like to say that I have no background in stats whatsoever and not so much in math either (enriched high school math, and that's it). I started an MA and we have to do a ...
1
vote
2answers
319 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 ...
3
votes
1answer
364 views

Simulating non-normal correlated data for Bayesian regression

I'm interested in generating data for three separate datasets where each contains three IVs and a single DV that are correlated with one another based on meta-analytic data. For example, I would like ...
3
votes
2answers
12k views

Egger’s linear regression method intercept in meta analysis

In Meta analysis, how to interpret the Egger’s linear regression method intercept (B0) 10.34631, 95% confidence interval (1.05905, 19.63357), with t=3.54535, df=3. The 1-tailed p-value (recommended) ...
3
votes
1answer
646 views

Interaction effects in network meta-analysis (multiple treatment comparison) in R?

I would like to use network meta-analysis (or multiple treatment comparison) to investigate the main-effect and interaction of two factors on a continuous outcome variable. As an example the effect of ...
3
votes
2answers
3k views

How to perform a meta-analysis of regression coefficients?

I want to perform a meta-analysis but the included studies use different models to analyze the data. There are Pearson correlation (3 studies), Spearman correlation (1 study) and several studies (~7-...
2
votes
1answer
514 views

Calculation for the estimated sampling variance of individual group raw mean

I am conducting a meta-analysis where the effect size is the individual group raw mean (i.e., not raw mean difference). A couple of questions: How (in R: metafor or otherwise) is the estimated ...
2
votes
2answers
8k views

Egger's test in SPSS

How can I conduct an Egger's test using SPSS17? For each study included in the meta-analysis I know effect size and sample size of patients and controls groups.
4
votes
1answer
927 views

Metafor package in R: Ranktest for multivariate meta analysis

I have done a multivariate meta analysis with R, with support from metafor package. I am using rma.mv-method which gives an R object of class c("rma.mv","rma"). My question is about looking for funnel ...
4
votes
1answer
3k views

Statistical comparison of 2 independent Cohen's ds

Is it possible to statistically compare the Cohen's $d$ of two studies in order to determine of one of the two Cohen's $d$s is statistically significantly larger (or smaller) than the other one? I ...
3
votes
3answers
438 views

How to assess effect of intervention in one state versus another using annual death rate data?

I am a beginner in statistics. I have these unpublished data (cases and deaths) of a disease for 7 years (2004-2010) from 2 neighbouring states. The study was started in 2004. State 1 and State 2 ...
2
votes
1answer
948 views

Logit or arcsine transformation for proportion in meta-analysis

I am performing a meta-analysis with 137 study arms. From each arm I have extracted a proportion of a disease. Here are my proportions: ...
2
votes
1answer
154 views

Is it ok to add a constant to the means in the log transformed ratio of means?

My colleagues and I were wondering if is OK to add a constant to the means in the log transformed ratio of means (known also as log response ratio). The log response ratio and its variance are: \...
2
votes
2answers
127 views

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 ...
2
votes
1answer
874 views

Meta-analysis in R of pre-post treatment design studies

I would like to conduct a meta-analysis in R of studies using a pre-post treatment design. In every individual study 4 different subgroups of patients have undergone a pharmacological treatment and ...
1
vote
1answer
383 views

Reporting of Heterogeneity in Metaanalysis

The background is a forest plot of a meta-analysis which is reported to have been calculated with a "random effects model". The pooled effect is reported as a standardized mean difference (SMD). ...
1
vote
2answers
97 views

Stouffer method

This is my question: I have to perform a mini-meta-analysis on two studies(independent, balanced sample) with a Repeated measures design and with two within factors. I have the F statistic and the p ...
1
vote
1answer
3k views

Deriving effect sizes form pre-post treatment design in R?

This question is related to my previous post. In case of a meta-analysis of a pre-post treatment design I have data given from 5 studies that tested subjects pre- and post-treatment on a continuous ...
0
votes
1answer
362 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 ...
17
votes
4answers
13k views

Combining two confidence intervals/point estimates

Suppose one has two independent samples from the same population, and different methods were used on the two samples to derive point estimate and confidence intervals. In trivial cases a sensible ...
11
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1answer
4k views

Does transformation of r into Fisher z benefit a meta-analysis?

Usually $r$ is transformed into Fisher $z$ to test difference between two $r$ values. But, when a meta-analysis is to be performed, why we should take such a step? Does it correct for measurement ...
7
votes
1answer
1k views

Is stratified meta-analysis more or less objective than meta-regression?

Reviewer asked me why I use meta-regression as a way how to deal with heterogeneity among effect sizes instead of conducting stratified meta-analysis. I tried to google "stratified meta-analysis" and ...
9
votes
1answer
13k views

How to calculate Standard Error of Odds Ratios?

I have two datasets from genome-wide association studies. The only information available is the odds ratio and the p-value for the first data set. For the second data set I have the Odds Ratio, p-...
12
votes
1answer
305 views

Is meta-analysis of odds ratios essentially hopeless?

In a recent paper Norton et al. (2018)$^{[1]}$ state that Different odds ratios from the same study cannot be compared when the statistical models that result in odds ratio estimates have ...