I'm wondering if there are confounding variables that are affecting this result. For example New York and New Jersey are some of the most regressive states defi

I'm wondering if there are confounding variables that are affecting this result. For example New York and New Jersey are some of the most regressive states defined as difference in funding levels between rich and poor school districts. I found this chart which shows each states: http://apps.urban.org/features/school-funding-do-poor-kids-get-fair-share/ http://apps.urban.org/features/school-funding-do-poor-kids-g... If race is a mediator for income levels and in turn funding level shouldn't the researchers here include the difference in funding levels between income levels into their model to determine the true performance per spent dollar? I might be wrong as I'm no expert in the field but I think these type of problems are what causal models try to address. I've really enjoyed "The book of why" by Judea Pearl on the topic. It got me interested in learning more about causality.