People say this so much that is now used as a way to dismiss any study. It’s almost becoming a meme.

I think is clear that the baseline of any study is that correlation does not imply causation. You start there. That’s a basic intelligent start. You never take for granted that one thing causes the other. The ideas is to try to identify if there are any potential paths for causation.

Otherwise there’s not even a point in sharing or discussing these studies.

I’m not saying that bringing this up is wrong, but does it need to be said so much? I think it’s more interesting to analyze beyond that and try to see if there’s causation. We already know there’s an abysmal amount of correlated things but there must be a percentage of those things which are in fact caused by another at a certain level. I would love these discussions to be more focused on this and not just doing the plain classic dismissal of “correlation doesn’t mean causation”.

It really is almost a meme. You could almost perfectly plug it into the "Learned Sage Points Out That Powerball Not As Much After Taxes" Onion article:

https://local.theonion.com/learned-sage-points-out-that-powe...

It needs to be said so much because people weaponize scientific studies in the pursuit of their political agenda, media twist headlines to get clicks, etc. I've lost track of the number of articles that bury the "the authors of the study caution against any definitive conclusion about causation/correlation"

If the goal is rhetoric and not truth, no amount of repeating droll truisms is going to prevent that. Additionally this comment thread has been fairly tame.

It doesn’t need to be said so much, obviously. I’ve counted what, 3 times so far in just this thread?

It doesn’t make you sound smarter.

> I think is clear that the baseline of any study is that correlation does not imply causation. You start there. That’s a basic intelligent start. You never take for granted that one thing causes the other. The ideas is to try to identify if there are any potential paths for causation.

You might start there, but an incredible number of people read the headline and think "oh man; I guess I gotta increase my iron intake".

It's said a lot because it's so easy to draw a false conclusion from correlations.

And what the parent is saying, is that a study like this is not just demonstrating correlation, otherwise there would be no point in publishing it.

If this were an observational study, I'd completely agree. In that case, it could be that people who eat better diets and do exercise happen to have lower iron levels, but it is the diet and exercise that makes them live longer, not the iron.

Our study actually used a different method! We found that the genes that raise iron levels in the blood also have an effect on how long and healthy we live. Since you don't get to choose the genes you are born with, this method is more robust to confounding. It's not perfect by any means, but it does provide reasonably robust evidence for a causal role of iron rather than just a correlation. Still, we would like to verify this in follow-up experiments, possibly using animal models.

but it might be a useful biomarker