8 ms·
> to establish causality when the effect size is large enough with a clear dose response curve. And when there's some plausible underlying mechanism that can
by mlyle 5y ago
> to establish causality when the effect size is large enough with a clear dose response curve.
And when there's some plausible underlying mechanism that can be studied by more rigorous means. Otherwise, observational studies can find correlation, not causation-- and they're not even very robust at that.
- nradov 5y agoNo the dose response curve alone can be sufficient. Remember that the FDA has approved multiple SSRI drugs for treating clinical depression despite a lack of understanding on the actual mechanism of action. There are several plausible hypotheses but we really don't know why they work.
- mlyle 5y agoA dose response curve in an observational study is irrelevant for establishing causation. There is a dose-response relationship between umbrellas outside and rainfall., but umbrellas do not cause rainfall. And the SSRI point is tangential: they were approved based on RCT evidence. Observing umbrella use and concluding it causes rainfall, even though we don't know of a reason why umbrella use would cause rainfall, is quite different.