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dc.contributor.authorColegrave, Nick
dc.contributor.authorRuxton, Graeme D.
dc.identifier.citationColegrave , N & Ruxton , G D 2017 , ' Statistical model specification and power : recommendations on the use of test-qualified pooling in analysis of experimental data ' , Proceedings of the Royal Society B: Biological Sciences , vol. 284 , no. 1851 , 20161850 .
dc.identifier.otherPURE: 249951372
dc.identifier.otherPURE UUID: 47202add-0276-4fba-84ff-ab78011bd107
dc.identifier.otherScopus: 85016107549
dc.identifier.otherPubMed: 28330912
dc.identifier.otherORCID: /0000-0001-8943-6609/work/60427539
dc.identifier.otherWOS: 000397884000002
dc.description.abstractCommon approach to the analysis of experimental data across much of the biological sciences is test-qualified pooling. Here non-significant terms are dropped from a statistical model, effectively pooling the variation associated with each removed term with the error term used to test hypotheses (or estimate effect sizes). This pooling is only carried out if statistical testing on the basis of applying that data to a previous more complicated model provides motivation for this model simplification; hence the pooling is test-qualified. In pooling, the researcher increases the degrees of freedom of the error term with the aim of increasing statistical power to test their hypotheses of interest. Despite this approach being widely adopted and explicitly recommended by some of the most widely cited statistical textbooks aimed at biologists, here we argue that (except in highly specialized circumstances that we can identify) the hoped-for improvement in statistical power will be small or non-existent, and there is likely to be much reduced reliability of the statistical procedures through deviation of type I error rates from nominal levels. We thus call for greatly reduced use of test-qualified pooling across experimental biology, more careful justification of any use that continues, and a different philosophy for initial selection of statistical models in the light of this change in procedure.
dc.relation.ispartofProceedings of the Royal Society B: Biological Sciencesen
dc.rights© 2017 The Author(s). Published by the Royal Society. All rights reserved. This work has been made available online in accordance with the publisher’s policies. This is the author created accepted version manuscript following peer review and as such may differ slightly from the final published version. The final published version of this work is available at
dc.subjectExperimental designen
dc.subjectModel simplificationen
dc.subjectQH301 Biologyen
dc.subjectImmunology and Microbiology(all)en
dc.subjectBiochemistry, Genetics and Molecular Biology(all)en
dc.subjectEnvironmental Science(all)en
dc.subjectAgricultural and Biological Sciences(all)en
dc.titleStatistical model specification and power : recommendations on the use of test-qualified pooling in analysis of experimental dataen
dc.typeJournal articleen
dc.contributor.institutionUniversity of St Andrews. School of Biologyen
dc.contributor.institutionUniversity of St Andrews. Centre for Biological Diversityen
dc.description.statusPeer revieweden

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