Why would you think that similar people living near each other is the result of a coincidence? Abject poverty is likely to have way more impact on kids perform

Why would you think that similar people living near each other is the result of a coincidence? Abject poverty is likely to have way more impact on kids performance in school than any level of school funding. Whether you want to lump that in with "children's efforts" or not, it's certainly exogenous to the school.