Often cited is a report that came out a few years ago.
It shows a 1970 Toronto where poverty is mostly concentrated in the urban core neighbourhoods. The majority of the city is made up of middle income neighbourhoods, which are mostly found in the post-WWII auto-oriented parts of the city.
Forward to 2005, and core neighbourhoods have gone from poor to more of a mix. The majority of the post-WWII neighbourhoods that were middle income became low income, and wealthy areas have gotten wealthier.
But what this mean for income diversity? A neighbourhood with a large wealthy and poor population might be middle income on average, but have a small middle class. You could also have a neighbourhood with a large middle class, but which is unable to attract wealthy residents and has zoned out low income residents.
Neighbourhoods with a high diversity of incomes are probably quite rare, especially those where the diversity exists at a highly local level, and where the neighbourhood's income diversity remains high for a significant period of time.
Here's a map showing income diversity of electoral districts across Toronto. Electoral districts have about 100,000 residents (more detailed map of boundaries here). A value of 0 means they perfectly match the CMA income distribution while high numbers represent high income segregation.
However, the electoral districts with the highest income diversity in the Toronto CMA are in the suburbs. The least diverse districts are in a variety of locations, some in the core, some in aging inner suburbs, and some in the outer suburbs, with a variety of income groups that are under or over-represented.
Here are graphs showing the income distributions of the 8 districts with the least income diversity.
There are a few differences between Oakville and places like North Etobicoke, although it's hard to say which are most important
-Less aging multi-family housing and housing projects
-Bigger lots, which means more space to build a big new home
-Close to the fastest and most frequent commuter rail line into Downtown Toronto
-Quaint downtown and close to Lake Ontario
Oakville-North Burlington is mostly large suburban developments built after 1990 in the northern parts of Oakville and Burlington.
Finally, you have the electoral districts with a small middle class.
So how about the districts with the highest income diversity, how well do they match the metro area's income distribution?
These could be described as middle ring suburbs. They have more new housing than the inner suburbs, and more older housing than the outer suburbs and are growing at rate somewhere in between.
*The numbers are based on comparisons of population in each decile of Canada's income distribution from the 2011 National Household Survey. Statistics Canada has adjusted for these incomes by dividing after tax family income by the square root of family size, so a family of 4 earning $100,000 after tax is considered on equal footing to a single earning $50,000. The numbers are the sum of the standard deviations between the fraction of the CMA population and the fraction of the electoral district population in each income decile. The 2013 electoral district boundaries are used.