3 ms·
> Meaning that the effect must be fairly strong to be observable in two studies with n=50? Do what now? Isn't the problem that it could have randomly happened
by tshaddox 3y ago
> Meaning that the effect must be fairly strong to be observable in two studies with n=50?
Do what now? Isn't the problem that it could have randomly happened (especially if people did a bunch of other similar studies that didn't observe an effect, and only these two were published)?
- epistasis 3y agoFor a publishable effect at smaller n, the effect size needs to be fairly large. If you have a huge number of people in a trial, you can get statistical significance of negligible consequence. The problem with a single study of n=50 isn't the 50, it's that it's a single study.
- jbullock35 3y agoThat's not quite right. If the study is underpowered at n = 50 --- which is extremely likely --- statistically significant estimates are likely to be inflated. And as power declines, they also become more likely to have the wrong sign (e.g., the study will yield a positive estimate even though the true effect is negative). See https://doi.org/10.1177/1745691614551642 https://doi.org/10.1177/1745691614551642.