And are you saying they have per-student household income data? Or they just have the household income data for the school district as a whole? Or maybe the household income data for the student body as a whole? Those are very different things.
I think we might be saying the same thing though, since “right” school generally means a school where a large proportion of the other kids have parents who are throwing a lot of resources at the kids (including the parents’ time and attitudes towards academic learning). It just so happens that this group of parents is higher income, so the easily visible statistic will be neighborhoods with higher income households will have higher academic proficiency percentages in the schools.
There is also this old map:
If you search niche.com, you can see proficiency scores correlate exactly with household income. Same school systems, same new facilities, same teacher compensation, same class sizes.