They're all correlated, sure, but how well have we determined causation for these? Childhood nutrition I'll grant: it has big, well-established long-term effect

They're all correlated, sure, but how well have we determined causation for these? Childhood nutrition I'll grant: it has big, well-established long-term effects on a lot of things. The rest look more shaky. Pre-kindergarten education, for example, has effects that look to be somewhere between tiny and nonexistent: https://slatestarcodex.com/2018/11/13/preschool-much-more-than-you-wanted-to-know/ https://slatestarcodex.com/2018/11/13/preschool-much-more-th... ... which hardly seems cost-effective.