[djcapelis]

You usually see a gradient where the tract-to-tract variance is less pronounced. A city will almost always contain tracts where there is a 10x difference between the highest and lowest numbers, but it is not as frequent that those tracts will be located right next to each other. There are several other cities which are like this, Delhi and to some extent Philadelphia both come to mind and I think it is notable there as well.

And, for whatever it's worth, I also think the variance even when the tracts are not next to each other is equally worthy of examination. Just because it is common does not mean it isn't something we shouldn't talk about. In many ways, when the neighborhoods are next to each other it is a good thing for visibility.

[tomkarlo]

New York has this... I don't think it's atypical. Tracts are so small that it only takes a single development to raise or depress median income grossly. Take a look at the middle of Manhattan: there are tracts with $10K next to tracts with $120K, but they might have as few as 20 households in tract, which means that a single building with 11 low-income tenants would pull the median down to the poverty line.

http://www.wnyc.org/blogs/wnyc-news-blog/2011/dec/08/census-...