Children who move out of high poverty neighborhoods to low poverty neighborhoods with more resources do better on multiple outcomes, and the younger they are when their families move the better. These conclusions come from a study of the long-term outcomes of the Moving to Opportunity Experiment.
Read some of the details and examine some of the results at:
http://www.equality-of-opportunity.org/
How effective are these data displays in conveying information?
What might be sources of invalidity in such a field experiment?
Researching in a Social World 