At the risk of sounding tautological: since underpowered studies only have the power to detect large effects, those are the only effects they see. This is where the logic leads. If you find an effect in an underpowered study, that effect is probably exaggerated.47 Then comes publication bias: since large effects are exciting effects, they’re much more likely to go on to get published. That’s why, when reading the scientific literature, so many tiny studies seem to be reporting big effects: as we saw with the funnel plots in the last chapter, journals are often missing all the small studies
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