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Main Authors: Panagiotopoulou, Kanella, Evrenoglou, Theodoros, Schmid, Christopher H, Metelli, Silvia, Chaimani, Anna
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2412.12945
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author Panagiotopoulou, Kanella
Evrenoglou, Theodoros
Schmid, Christopher H
Metelli, Silvia
Chaimani, Anna
author_facet Panagiotopoulou, Kanella
Evrenoglou, Theodoros
Schmid, Christopher H
Metelli, Silvia
Chaimani, Anna
contents Random effects meta-analysis is widely used for synthesizing studies under the assumption that underlying effects come from a normal distribution. However, under certain conditions the use of alternative distributions might be more appropriate. We conducted a systematic review to identify articles introducing alternative meta-analysis models assuming non-normal between-study distributions. We identified 27 eligible articles suggesting 24 alternative meta-analysis models based on long-tail and skewed distributions, on mixtures of distributions, and on Dirichlet process priors. Subsequently, we performed a simulation study to evaluate the performance of these models and to compare them with the standard normal model. We considered 22 scenarios varying the amount of between-study variance, the shape of the true distribution, and the number of included studies. We compared 15 models implemented in the Frequentist or in the Bayesian framework. We found small differences with respect to bias between the different models but larger differences in the level of coverage probability. In scenarios with large between-study variance, all models were substantially biased in the estimation of the mean treatment effect. This implies that focusing only on the mean treatment effect of random effects meta-analysis can be misleading when substantial heterogeneity is suspected or outliers are present.
format Preprint
id arxiv_https___arxiv_org_abs_2412_12945
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Meta-analysis models relaxing the random effects normality assumption: methodological systematic review and simulation study
Panagiotopoulou, Kanella
Evrenoglou, Theodoros
Schmid, Christopher H
Metelli, Silvia
Chaimani, Anna
Methodology
Random effects meta-analysis is widely used for synthesizing studies under the assumption that underlying effects come from a normal distribution. However, under certain conditions the use of alternative distributions might be more appropriate. We conducted a systematic review to identify articles introducing alternative meta-analysis models assuming non-normal between-study distributions. We identified 27 eligible articles suggesting 24 alternative meta-analysis models based on long-tail and skewed distributions, on mixtures of distributions, and on Dirichlet process priors. Subsequently, we performed a simulation study to evaluate the performance of these models and to compare them with the standard normal model. We considered 22 scenarios varying the amount of between-study variance, the shape of the true distribution, and the number of included studies. We compared 15 models implemented in the Frequentist or in the Bayesian framework. We found small differences with respect to bias between the different models but larger differences in the level of coverage probability. In scenarios with large between-study variance, all models were substantially biased in the estimation of the mean treatment effect. This implies that focusing only on the mean treatment effect of random effects meta-analysis can be misleading when substantial heterogeneity is suspected or outliers are present.
title Meta-analysis models relaxing the random effects normality assumption: methodological systematic review and simulation study
topic Methodology
url https://arxiv.org/abs/2412.12945