Isn't that what you'd expect? There's a factor of ten difference these days between the poverty line and a fairly typical white-collar income (call it $120K.) Is it really surprising, or telling, that at the tract-level you'd find a factor of ten difference in a major city? Is there a major city where you don't see that?
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.
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.
$120K is typical? Even if you only isolate the executive/management positions from SF, which is one of the most inflated markets in the world, the median is still only about $100k. Obviously, the average of all white-collar jobs will be far lower. In more representative parts of the country, I'd imagine that it's below $50k (which is only two to four times the poverty level, not ten.)
Honestly, where do people get the idea that the average American makes $120k. That salary is astronomical.
I specifically called it out as "white-collar" income, not overall median income.
It's household income, not per capita. The median household income for SF is $73. I don't think it's out of bounds to assume that for a white collar worker (call it a 75th percentile income) that number is well over $120.
About 30% of the US gets a bachelor's degree, which seems like a reasonable proxy for the number of people working in white collar office jobs. So a median white collar worker is probably about 80th percentile income. For the overall US, that works out to $105K to $110K.
http://en.wikipedia.org/wiki/Household_income_in_the_United_...
