This is pretty normal. You have to run multiple studies before you can draw any conclusions. The studies start small, and if they find anything of note, there a

This is pretty normal. You have to run multiple studies before you can draw any conclusions. The studies start small, and if they find anything of note, there are bigger, more expensive follow-up studies. This is a good reason why you shouldn't draw conclusions from just 1 study, or even 2 studies. You need a significant body of scientific evidence before you can conclusively say "X causes Y"