[rayiner]

You have to keep in mind that city limits are rather arbitrary, and San Francisco is unusual in drawing them very tightly, excluding SFO and excluding low-density commercial areas along the bay. Meanwhile, Chicago's boundaries include both O'Hare and Midway, and stretch south through industrial areas all the way to Indiana. But the the cheap land in Pullman doesn't affect the price of land in the Loop any more than the cheap land in San Bruno affects the price of land in SOMA, city limits not withstanding.[1] Those properties aren't fungible from the perspective of potential buyers.

The part of Chicago north of 95th street (the southern boundary of the 'El' system) and outside the airports has 2.5 million people (93% the population) at a density of ~16,500 per square mile, comparable to San Francisco. Yes, it's somewhat arbitrary to exclude part of the city in calculating density, but no less arbitrary than where San Francisco's southern boundary is drawn, ten miles short of its airport.

[1] This isn't to say that those areas "aren't part of Chicago" culturally and in other ways, just that the availability of land in those areas shouldn't have much impact on housing prices in the rest of the city.

[tptacek]

Chicago is somewhat less dense than San Francisco even in a neighborhood-by-neighborhood comparison.

If you go through stats per neighborhood and cut off at 20k/sqm, you'll see that San Francisco has a lot of neighborhoods over that cutoff. It's true that Chicago's dense neighborhoods are much bigger than San Francisco's; for instance, The Mission is an SF standout at 1.4sqm, while Chicago has many dense neighborhoods at 2-4sqm (Lakeview, West Town, Logan Square).

But if you add up all the little SF neighborhoods, I suspect you'll get a bigger number of dense square miles in SF. SF also has some absurdly dense neighborhoods (Chinatown, Downtown); they're tiny, but north of 50k/sqm.

It's pretty obvious that Chicago has an inherent advantage in sheer land area; huge tracts of Chicago are residential neighborhoods of bungalows on lots with back yards, which is a kind of home you can get in Chicago very inexpensively, but is priced out of reach for most people in SF. These areas relieve a lot of density pressure in other parts of the city; if you live in a dense neighborhood in Chicago, it's because you want to.

[rayiner]

In the 2010 census, Chicago has 11 community areas above 20k/sqm, with 708k people in about 29 sqm (average density = 25k/sqm). Throw in West Town (18k/sqm) and the Loop (19k/sqm), and its 818k people in 35 sqm (average density = 23k/sqm). That's almost a San Francisco worth of dense neighborhoods both in population and area. And its not like SF is uniformly that dense. Parts remind me of the suburbs where my parents live in VA. Huge yards, etc.

I don't disagree that San Francisco is somewhat more dense as a whole, but I still contend that the density angle is overweighted. I think city planning plays a huge role, not just in limiting densities (given the geography of the city, density should be more like Manhattan, not like Chicago) and also making less dense areas harder to access. There are huge tracts of residential neighborhoods in Chicago with back yards and bungalows, but they're often pretty close to an 'El' station or a METRA station. That takes a lot of pressure off housing prices downtown. Meanwhile, tons of land on the Peninsula less than 10 miles from downtown have no practical public transit besides one BART line. The McSuburbs of DC have better rail access, and that's sad.

[tptacek]

Oh, don't get me wrong. Chicago is a better designed, better managed, more livable city than San Francisco.