Hi Gord,
Concentrated poverty does indeed impact cities, their neighbourhoods, and the children that grow up there. I’m not seeking to provide an evaluation of the DTES. That is a worthwhile study! But perhaps it is worthwhile to suggest that all “community” is not “healthy community.” It may be possible that a neighbourhood’s efforts at community are actually dysfunctional in regards to generating movement toward a vision of healthy people and relationships. Concentrated poverty and the “20% threshold” has been researched in North American cities and may prove helpful to your exploration. I think its likely that the concept of “social mix” is tied into some of that research.

Here’s a Brookings article about the “re-emergence” of concentrated poverty in American cities: http://www.brookings.edu/~/media/research/files/papers/2011/11/03%20poverty%20kneebone%20nadeau%20berube/1103_poverty_kneebone_nadeau_berube.pdf