Lesson from an obscure something or other
Listening to some obscure AM radio show about travel or cars or something.... they're interviewing someone who rated the highways of each state for safety and convenience. Obviously I wasn't listening very carefully!... until he said ONE thing that made tremendous sense.
"We didn't use highway budget as a criterion. If a state spends a lot of money, that could mean it wants good highways; or it could mean there's a lot of corruption; or it could mean they have terrible highways that need a lot of repair."
Perfect logic.
But we're not allowed to apply the same logic to education, even though it's clearly the very same principle. A state that spends a lot on education could be trying to get the best; or it could be wasting most of the money in corruption; or it could be spending to keep poor facilities barely above water.
Nope, we just blindly assume that more spending means better graduates.