
You may not remember, but in your Econ 101 class way back
when, you probably learned the terms “non-excludable” and “non-rivalrous.”
Given that your eyes probably glazed over when you read those arcane phrases,
you can be forgiven for wondering why I am attempting to construct a blog post
on the subjects.
Bear with me while I further nerd out by trying to define these
concepts:
1. A “non-excludable” good is one that you can’t
really keep someone from freely enjoying. Once you secure national defense or
clean air, you can’t easily prevent someone from reaping the benefits from
them. Conversely, country club membership and running shoes are not universally
available because you have to pay to access them.
2. A “non-rivalrous” good is one that, if I am
enjoying it does not crowd out others from also enjoying it. Public parks and
public sidewalks are good examples of “non-rivalrous” goods, because my
accessing them does not meaningfully restrict others from also enjoying them. A
country club membership, while being excludable, is also non-rivalrous, because
my being a member does not adversely affect your being a member. Running shoes
are rivalrous, though, since once I buy and own a pair, you can’t buy and own
that pair too.
Having bored you to tears or perhaps stirred a faint memory
from your undergrad days, let me get to the point of this post, which is that
cities, at their best, are non-excludable and non-rivalrous goods. Which may
seem obvious, but I want to further assert that they non-excludable and non-rivalrous
in ways that suburbs are not.
This is all another way of saying what Paul Levy, founder of
Center City District in Philadelphia, has long said, which is that in cities,
more is more, whereas in suburbs, more is less. To restate this insight, more people
in the suburbs means more traffic, more difficulty in finding parking, and
perhaps other congestion issues that either diminish your enjoyment (e.g. the
pool at the community center is crowded so you have to wait for a lane to open)
or sock your tax bill (e.g. enrollment increases necessitate that your school
district invest in expanding capacity).
Most cities, particularly in the Northeast and Midwest, are
still well below their highest historic population levels. Which means that
most of those cities’ main infrastructure can support many more people that
current population levels. Roads, bridges, transit systems, schools, park
systems, and so on may be in need of investment (more on this in a sec), but
they exist in a way that can be scaled to meet any rising demand should
population go up significantly from current levels. Another way I like to say
this is that cities in the West and Sunbelt are levying taxes to raise tens of
billions of dollars for the kinds of things that Northeast and Midwest already have
in place, like mass transit and park systems.
These public goods, and cities as a whole, are
non-excludable and non-rivalrous, because much of what is good and enjoyable
about a city is available to all and does not diminish but rather gets enhanced
as there are more and more people there enjoying themselves. A bustling
downtown does not portend traffic and parking issues as much as it creates a
sense of safety in numbers and a vibrancy that comes from people watching and
bumping into colleagues. Even a vibrant shopping and restaurant district, which
may cost money to purchase food and goods, is free for folks to walk through without
anyone feeling like they can be excluded or crowded out.
Ah, there’s a caveat. In fact, in the history of cities
there have been occasions in which some people are made to not feel welcome,
either by public pressure or official policy, so maintaining a welcoming and
inclusive spirit takes work to overcome past barriers. And, the ability for
cities to scale requires the existence and upkeep of mass transit to move
people en masse, lest people choose to or have to drive, which does in fact
have a diminishing effect on the value of density.
Cities, at their best, are non-excludable and non-rivalrous
goods. But it takes work. Let’s hope we are willing to put in that work.