Can you please point me to an under-performing school with that ratio? In my experience, the under-performing schools receive between 50% and 100% percent more funding than high performing schools and have very low teacher student ratios. Thanks.

Mississippi is one of the worst performing states in the US (by multiple metrics[0]), to quote state policy (Mississippi Code Ann. Section 37-151-77):

> 28.3 Student teacher ratios do not exceed 30 to 1 in self-contained classes serving grades 5-8. {MS Code 37-151-77} A one-year waiver may be requested for classes that do not exceed more than two (2) students beyond the allowable student teacher ratio.

And:

> 28.4 Student teacher ratios do not exceed 33 to 1 in departmentalized academic core classes serving grades 5-12. {MS Code 37-151-77} A one-year waiver may be requested for classes that do not exceed more than two (2) students beyond the allowable student teacher ratio.

[0] https://www.gulflive.com/news/2019/07/mississippis-school-sy...

[1] Jackson Public School District documentation which is a succinct list of State limits: https://www.jackson.k12.ms.us/cms/lib/MS01910533/Centricity/...

White 8th graders in Mississippi average the same in mathematics testing as white 8th graders in Vermont or New Hampshire. (In reading they're 1 point behind.)

Mississippi's average is only low because they have a large black population, and they do better than black kids in Arkansas, Louisiana, and Alabama, but worse than Tennessee and Georgia.

You can see here:

https://www.nationsreportcard.gov/mathematics/states/groups/...

Mississippi is a poor state, but within Mississippi, do the better performing schools receive more funding?

Positive impact is hard, but there are certainly terrible teachers who have a strong negative impact but are sheltered by teachers' unions. The best case is places like New York that have the notorious "rubber rooms" where they are exiled so at least they can do no further harm to students, while remaining a drain on public finances.

The problem is you can't use data science to find them. Any metric can and will be gamed. It requires a qualitative assessment, and also giving parents more power in the system, since they are the ones most aligned with the interests of students.

Parents more power in the system is a bit of a double edged sword.

For every story about a teacher doing poorly teachers often have them of parents refusing to believe that their child could ever do anything wrong, like cheating or bullying behavior.