The Return of the Spatial Mismatch Hypothesis

How much of center city resident poverty is caused by physical distance from suburban jobs?   The “spatial mismatch hypothesis” posits that the answer is “a lot”.   The core story is that the urban center city poor are poor because they can’t easily commute to suburban jobs. Free cars might solve this problem!   Glaeser and I discuss job sprawl in this paper.   My colleague Michael Stoll (and my friend Steve Raphael) have written about the social benefits of increasing access to cars for the urban poor.  In today’s NY Times, Paul Krugman endorses the key role for the spatial mismatch theory.     John Kain, the great late Harvard economist, wrote the best early paper on this subject and revisited the topic in this 1992 paper.    John Quigley,   my co-author and good friend who died in 2012, wrote one of the better natural experiment papers using the BART expansion to test for the impact  of spatial mismatch.

Now for policy wonks, the spatial mismatch hypothesis is an attractive idea because it suggests that through improving urban travel speeds that economic opportunity will increase.   The true test of this optimistic hypothesis would be to take center city residents and randomly choose a subset to live closer to suburban jobs and then to later test whether this “treated” group is now more likely to be employed and earning higher wages relative to the “stranded” control group.  Such a field experiment has been slightly tried with the MTO experiments and unfortunately the answer appears to be “no”.  Take a look at this.  

Author: Matthew E. Kahn

Professor of Economics at UCLA.

6 thoughts on “The Return of the Spatial Mismatch Hypothesis”

  1. The use of the linked MTO paper as a “true test” of the spatial mismatch hypothesis, though, is problematic in that it really doesn’t get at the primary mechanism postulated by SMH adherents: physical access to jobs. The linked paper doesn’t model differences in access between movers and non-movers, but other work indicates that MTO movers don’t, in fact, improve their physical access to jobs, making MTO data moot with respect to claims about the link between access and employment outcomes (see Yingling Fan’s “The Planners’ War against Spatial Mismatch: Lessons Learned and Ways Forward” for a very good summary of the literature).

    For the record, I think that Krugman overstates the link between sprawl and economic immobility, and that the relevant literature points toward having a car as a bigger factor than geography in gaining access to work. But I also don’t think that there’s much great evidence to be drawn from MTO here.

  2. Sure, moving people to jobs will fix Detroit’s problems. Let’s build a system to do that and call it “The People Mover”!

    Oh wait…

    1. If you have any idea what the People Mover is, you realize why you comment makes too little sense to be funny.

  3. If you were doing a study and planned to use it to demonstrate that lack of mobility was affecting job prospects, Boston, with its very good transit and high percentage of center-city jobs is possibly the worst place in America you could pick.

    1. Not to mention that the link is to “early results”.

      Nut most important, Matthew’s summary is really a mischaracterization of the new version of the spatial mismatch hypothesis. It’s not so much about whether people can get closer to the “good jobs” in the suburbs, it’s about whether suburbs have the kinds of job distributions that allow significant numbers of poor people to get out of poverty period.

      First, of course, there’s the transit issue: working and living in a modern suburb requires a car, which effectively adds several hundred dollars a month to the basic budget and reduces the reliability of transport. And imposes a time tax that will make it hard to handle childcare or ater-work study or anything else outside a job.

      Even more (anecdotally at least) suburbs also just don’t have as many of the kinds of jobs that would serve as transitions from poverty and relative lack of skills to middle and upper echelons. Food service and retail aren’t going to get you there. And office parks are likely out of reach for the bottom quintile.

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