Nicola Romanò<p>When designing a scientific experiment, a key factor is the sample size to be used for the results of the experiment to be meaningful.</p><p>How many cells do I need to measure? How many people do I interview? How many patients do I try my new drug on?</p><p>This is of great importance especially for quantitative studies, where we use statistics to determine whether a treatment or condition has an effect. Indeed, when we test a drug on a (small) number of patients, we do so in the hope our results can generalise to any patient because it would be impossible to test it on everyone.</p><p>The solution is to perform a "power analysis", a calculation that tells us whether given our experimental design, the statistical test we are using is able to see an effect of a certain magnitude, if that effect is really there. In other words, this is something that tells us whether the experiment we're planning to do could give us meaningful results.</p><p>But, as I said, in order to do a power analysis we need to decide what size of effect we would like to see. So... do scientists actually do that?</p><p>We explored this question in the context of the chronic variable stress literature.</p><p>We found that only a few studies give a clear justification for the sample size used, and in those that do, only a very small fraction used a biologically meaningful effect size as part of the sample size calculation. We discuss challenges around identifying a biologically meaningful effect size and ways to overcome them.</p><p>Read more here!<br><a href="https://physoc.onlinelibrary.wiley.com/doi/10.1113/EP092884" rel="nofollow noopener" target="_blank"><span class="invisible">https://</span><span class="ellipsis">physoc.onlinelibrary.wiley.com</span><span class="invisible">/doi/10.1113/EP092884</span></a></p><p><a href="https://qoto.org/tags/experiments" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>experiments</span></a> <a href="https://qoto.org/tags/ExperimentalDesign" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ExperimentalDesign</span></a> <a href="https://qoto.org/tags/effectsize" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>effectsize</span></a> <a href="https://qoto.org/tags/statistics" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>statistics</span></a> <a href="https://qoto.org/tags/stress" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>stress</span></a> <a href="https://qoto.org/tags/research" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>research</span></a> <a href="https://qoto.org/tags/article" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>article</span></a> <a href="https://qoto.org/tags/power" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>power</span></a> <a href="https://qoto.org/tags/biology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>biology</span></a></p>