system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If correlation is not causation, how(why) can(do) we believe scientific studies?
gpt
Scientific studies that are believable aim to prove the cause, not the correlation.  

Take drug studies.  They use similar populations, and split them in to groups.  One group gets nothing, one group gets a placebo (sugar pill basically), and one group gets some drug.  Then they study each population to determine if the drug does anything good or bad, how each population compares in their tolerance of the drug and their recovery time, and so forth.  It may be that a drug doesn't shorten the duration of an illness, so they don't proceed with it. But the proof is there.

It's completely different from scenarios where, for example, children who learned to walk early on also tend to suffer from allergies.  i heard it on Oprah.  Srs.