UMMS Affiliation

Department of Population and Quantitative Health Sciences

Publication Date

2020-10-22

Document Type

Article

Disciplines

Investigative Techniques | Research Methods in Life Sciences | Statistics and Probability

Abstract

BACKGROUND: For outcomes that studies report as the means in the treatment and control groups, some medical applications and nearly half of meta-analyses in ecology express the effect as the ratio of means (RoM), also called the response ratio (RR), analyzed in the logarithmic scale as the log-response-ratio, LRR.

METHODS: In random-effects meta-analysis of LRR, with normal and lognormal data, we studied the performance of estimators of the between-study variance, tau(2), (measured by bias and coverage) in assessing heterogeneity of study-level effects, and also the performance of related estimators of the overall effect in the log scale, lambda. We obtained additional empirical evidence from two examples.

RESULTS: The results of our extensive simulations showed several challenges in using LRR as an effect measure. Point estimators of τ2 had considerable bias or were unreliable, and interval estimators of τ2seldom had the intended 95% coverage for small to moderate-sized samples (n

CONCLUSIONS: For lognormal data, we can recommend only SSW, a weighted average in which a study's weight is proportional to its effective sample size, (when n≥40) and its companion interval (when n≥10). Normal data posed greater challenges. When the means were far enough from 0 (more than one standard deviation, 4 in our simulations), SSW was practically unbiased, and its companion interval was the only option.

Keywords

Between-study variance, Heterogeneity, Log-response-ratio, Meta-analysis, Random-effects model, Ratio of means

Rights and Permissions

© The Author(s). Open Access: This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

DOI of Published Version

10.1186/s12874-020-01137-1

Source

Bakbergenuly I, Hoaglin DC, Kulinskaya E. Estimation in meta-analyses of response ratios. BMC Med Res Methodol. 2020 Oct 22;20(1):263. doi: 10.1186/s12874-020-01137-1. PMID: 33092521; PMCID: PMC7579974. Link to article on publisher's site

Journal/Book/Conference Title

BMC medical research methodology

Related Resources

Link to Article in PubMed

PubMed ID

33092521

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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