Here's something I got from doing a quick google search. I'll give you 

other stuff as well. 

The main problem is that in Shiller's quest to provide more subsidized 

housing in an area that already exceeds DHS and CHA standards, she is 

actually causing concentrated poverty. Concentrated poverty traps the 

poor, it doesn't liberate them. If she really wanted to help the poor, 

she would seek a greater balance. Instead, she polarizes the community to 

have a war between the have's and the have not's. That's a divide and 

conquor approach that is her way of keep power. It certainly doesn't 

help the poor.

http://www.stanford.edu/~mrosenfe/urb_notes_neighborhood_effects.htm

Some Notes on Neighborhood Effects:

1) Disinvestment leads to decay of a few properties.  Decay of those 

properties lowers the value and desirability of each property on the 

block.  This leads to disinvestment in surrounding properties.  More 

properties are left to decay, and the downward spiral begins.

2) Neighborhood safety is a function of knowing your neighbors, and 

collective trust.  Low rates of home ownership increases the transient 

nature of the population, which decreases the ability of communities to 

organize.  High rates of crime in the neighborhood decrease the 

neighbors' willingness to trust each other.  Abandoned buildings serve as foci 

for crime, and low levels of trust and neighborhood organization leave 

the population vulnerable to ever increasing rates of crime.

3) Concentrated poverty drastically lowers the number of adults who 

have the kind of responsible jobs that can serve as an example to the 

youth.

4) Public schools serve neighborhoods.  As the neighborhood enters a 

state of decline, it becomes more difficult to attract skilled teachers.  

As safety of the children in and around the school becomes more of a 

problem, it becomes more problematic for parents to leave the children at 

school and go to work.

5) Because of concentrated poverty, ghetto neighborhoods can't support 

the kind of retail markets and social service providers that they 

need.  As a result, ghetto residents have to travel further and pay more for 

services.  Ghetto residents pay more for milk and pampers at the corner 

store than downtown residents pay at the supermarket, because the 

corner store buys in small quantities, and the corner store pays higher 

insurance rates.