They're not comparable on the same scale. Say... Kids get 10.5 years schooling on average in neighborhood A. 12 years in neighborhood B. That is a 1.5 years or

They're not comparable on the same scale. Say... Kids get 10.5 years schooling on average in neighborhood A. 12 years in neighborhood B. That is a 1.5 years or 15% difference. In a 12 grade system, this is the best possible result implying a 100% completion rate. Neighborhood A sends 10% of all kids to college. Neighborhood B sends 50% of all kids to college. That's a 500% difference. This example seems pretty plausible. A neighborhood where an average kid makes it halfway through 10th grade probably sends a lot fewer kids to college than a neighborhood with a 100% completion rate for grade 12.