Never mind what it measures. My main point is that whatever it is, it's not simply "dollars spent on prep". Good tests provide an opening for the less well-off

Never mind what it measures. My main point is that whatever it is, it's not simply "dollars spent on prep". Good tests provide an opening for the less well-off to succeed, despite the more well-off doing everything they can to rig it in their favor. My parents (and by extension me) owe a lot to them.