How much variance can be explained by ecologists and evolutionary biologists?
Abstract
The average amount of variance explained by the main factor of interest in ecological and evolutionary studies is an important quantity because it allows evaluation of the general strength of research findings. It also has important implications for the planning of studies. Theoretically we should be able to explain 100% of the variance in data, but randomness and noise may reduce this amount considerably in biological studies. We performed a meta-analysis using data from 43 published meta-analyses in ecology and evolution with 93 estimates of mean effect size using Pearson's r and 136 estimates using Hedges' d or g. This revealed that (depending on the exact analysis) the mean amount of variance (r 2 ) explained was 2.51-5.42%. The various 95% confidence intervals fell between 1.99 and 7.05%. There was a strongly positive relationship between the fail-safe number (the number of null results needed to nullify an effect) and the coefficient of determination (r 2 ) or effect size. Analysis at the level of individual tests of null hypotheses showed that the amount of variance key factors explained differed among fields with the largest amount in physiological ecology, lower amounts in ecology and the lowest in evolutionary studies. In all fields though, the hypothesized relationship (e.g. main effect of a fixed treatment) explained little of the variation in the trait of interest. Our finding has important implications for the interpretation of scientific studies. Across studies…
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
In complex systems such as animal communities and ecosystems, the relationship between measurable variables is rarely high, as shown by a review of meta-analyses in ecology (r = 0.18, CI [0.15, 0.21]).
“In complex systems such as animal communities and ecosystems, the relationship between measurable variables is rarely high, as shown by a review of meta‐analyses in ecology (r = 0.18, CI [0.15, 0.21]; Møller & Jennions, 2002).”
From Acoustic indices as proxies for biodiversity: a meta‐analysis (2022) · cites this paper as Møller & Jennions, 2002
Cites
Operating characteristics of a rank correlation test for publication bias
Begg, C. B., & Mazumdar, M. (1994) · Biometrics · doi:10.2307/2533446 · Cited by 16,955 · see citing works
Methods of Meta-Analysis: Correcting Error and Bias in Research Findings
Schmidt, F. L., & Hunter, J. E. (2015) · doi:10.4135/9781483398105 · Cited by 5,542 · see citing works
Flagged first, then by citations
Cited by
Sorted by citations
Rosenberg, M. S. (2005) · Evolution · doi:10.1111/j.0014-3820.2005.tb01004.x · Cited by 1,285 · see citing works
Tamim, R. M., Bernard, R. M., Borokhovski, E., Abrami, P. C., & Schmid, R. F. (2011) · Review of Educational Research · doi:10.3102/0034654310393361 · Cited by 1,029 · see citing works
“Positive” results increase down the Hierarchy of the Sciences
Fanelli, D. (2010) · PLoS ONE · doi:10.1371/journal.pone.0010068 · Cited by 734 · see citing works
Haidt, J., & Joseph, C. (2008) · The Innate Mind, Volume 3 · doi:10.1093/acprof:oso/9780195332834.003.0019 · Cited by 650 · see citing works
Detecting and avoiding likely false‐positive findings – a practical guide
Forstmeier, W., Wagenmakers, E., & Parker, T. H. (2017) · Biological Reviews · doi:10.1111/brv.12315 · Cited by 436 · see citing works
The seven deadly sins of comparative analysis
FRECKLETON, R. P. (2009) · Journal of Evolutionary Biology · doi:10.1111/j.1420-9101.2009.01757.x · Cited by 339 · see citing works
Species richness and wood production: a positive association in Mediterranean forests
Vilà, M., Vayreda, J., Comas, L., Ibáñez, J. J., Mata, T., & Obón, B. (2007) · Ecology Letters · doi:10.1111/j.1461-0248.2007.01016.x · Cited by 311 · see citing works
A survey of the statistical power of research in behavioral ecology and animal behavior
Jennions, M. D. (2003) · Behavioral Ecology · doi:10.1093/beheco/14.3.438 · Cited by 278 · see citing works
Self-citationAcoustic indices as proxies for biodiversity: a meta‐analysis
Alcocer, I., Lima, H., Sugai, L. S. M., & Llusia, D. (2022) · Biological Reviews · doi:10.1111/brv.12890 · Cited by 273 · see citing works
“Similarly, we looked for publication bias due to a potential relationship between journal impact factor and effect size (Møller & Jennions, 2002).”
BackgroundMethodInfluentialDynamic Human Environmental Exposome Revealed by Longitudinal Personal Monitoring
Jiang, C., Wang, X., Li, X., Inlora, J., Wang, T., Liu, Q., & Snyder, M. (2018) · Cell · doi:10.1016/j.cell.2018.08.060 · Cited by 218 · see citing works
Meta-analysis in applied ecology
Stewart, G. (2010) · Biology Letters · doi:10.1098/rsbl.2009.0546 · Cited by 214 · see citing works
Transparency in Ecology and Evolution: Real Problems, Real Solutions
Parker, T. H., Forstmeier, W., Koricheva, J., Fidler, F., Hadfield, J. D., Chee, Y. E., Kelly, C. D., Gurevitch, J., & Nakagawa, S. (2016) · Trends in Ecology & Evolution · doi:10.1016/j.tree.2016.07.002 · Cited by 201 · see citing works
Pasanen, T. P., Tyrväinen, L., & Korpela, K. M. (2014) · Applied Psychology: Health and Well-Being · doi:10.1111/aphw.12031 · Cited by 196 · see citing works
Virological factors that increase the transmissibility of emerging human viruses
Geoghegan, J. L., Senior, A. M., Di Giallonardo, F., & Holmes, E. C. (2016) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.1521582113 · Cited by 155 · see citing works
Rising complexity and falling explanatory power in ecology
Low-Décarie, E., Chivers, C., & Granados, M. (2014) · Frontiers in Ecology and the Environment · doi:10.1890/130230 · Cited by 111 · see citing works
How to critically read ecological meta-analyses
Lortie, C. J., Stewart, G., Rothstein, H., & Lau, J. (2015) · Research Synthesis Methods · doi:10.1002/jrsm.1109 · Cited by 39 · see citing works
- Authors
- Møller, A., & Jennions, M. D.
- Affiliations
- Centre National de la Recherche Scientifique (FR)
- Australian National University (AU)
- Corresponding author
- Møller, Anders
- Venue
- Oecologia
- Published
- 2002-08
- Volume
- 132
- Issue
- 4
- Pages
- 492-500
- ISSN
- 0029-8549 (ISSN-L)
- 1432-1939
- OpenAlex
- W2132059682
- Cited by
- 553
- References
- 2
- Citations by year
- 2026: 26 · 2025: 21 · 2024: 15 · 2023: 26 · 2022: 19 · 2021: 39 · 2020: 26 · 2019: 22 · 2018: 33 · 2017: 18 · 2016: 27 · 2015: 24 · 2014: 30 · 2013: 23 · 2012: 22
- FWCI
- 24.44
- Type
- journal article
- Language
- en
- Open access
- closed
- Licence
- www.springer.com/tdm (tdm)
- Locations
- Oecologia (publishedVersion)
- PubMed (publishedVersion)
- ANU Open Research (Australian National University) (submittedVersion)
- Smithsonian Digital Repository (Smithsonian Institution) (submittedVersion)
- Topics
- Social Sciences › Decision Sciences › Statistics, Probability and Uncertainty › Meta-analysis and systematic reviews
- Social Sciences › Psychology › Experimental and Cognitive Psychology › Psychology Research and Bibliometrics
- Social Sciences › Decision Sciences › Statistics, Probability and Uncertainty › scientometrics and bibliometrics research
- Keywords
- explained variance, effect size, statistical power, sample size, null hypothesis testing, ecological study, evolutionary studies, statistical significance, study design planning
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review