Four simple ways to increase power without increasing the sample size
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Abstract
Underpowered experiments have three problems: the probability of a false positive result is higher, true effects are harder to detect, and the true effects that are detected tend to have inflated effect sizes. Many biology experiments are underpowered and recent calls to change the traditional 0.05 significance threshold to a more stringent value of 0.005 will further reduce the power of the average experiment. Increasing power by increasing the sample size is often the only option considered, but more samples increases costs, makes the experiment harder to conduct, and is contrary to the 3Rs principles for animal research. We show how the design of an experiment and some analytical decisions can have a surprisingly large effect on power.
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2017. Four simple ways to increase power without increasing the sample size. PeerJ Preprints 5:e3363v1 https://doi.org/10.7287/peerj.preprints.3363v1Author comment
This is a preprint submission to PeerJ Preprints.
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R code to reproduce the figures and analyses.
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Competing Interests
The authors declare that they have no competing interests.
Author Contributions
Stanley E Lazic conceived and designed the experiments, performed the experiments, analyzed the data, contributed reagents/materials/analysis tools, wrote the paper, prepared figures and/or tables, reviewed drafts of the paper.
Funding
The authors received no funding for this work.
