THE META-ANALYSIS OF RESPONSE RATIOS IN EXPERIMENTAL ECOLOGY

TLDR

Meta‑analysis offers formal statistical techniques for summarizing independent experiments and is increasingly applied in ecology, where the response ratio is a common effect size metric. The study aims to derive the statistical properties of the response ratio to enable its use in ecological meta‑analysis. The authors approximate the sampling distribution of the log response ratio, explain its advantages, and illustrate its application to CO2‑induced plant biomass data.

Abstract

Meta-analysis provides formal statistical techniques for summarizing the results of independent experiments and is increasingly being used in ecology. The response ratio (the ratio of mean outcome in the experimental group to that in the control group) and closely related measures of proportionate change are often used as measures of effect magnitude in ecology. Using these metrics for meta-analysis requires knowledge of their statistical properties, but these have not been previously derived. We give the approximate sampling distribution of the log response ratio, discuss why it is a particularly useful metric for many applications in ecology, and demonstrate how to use it in meta-analysis. The meta-analysis of response-ratio data is illustrated using experimental data on the effects of increased atmospheric CO2 on plant biomass responses.