The Urbanist Musings of Pete Saunders

CSY At Forbes — Why Most Cities Will Never Be All They Used To Be

A general view of Chicago on day 3 at Lollapalooza in Grant Park on Saturday, July 30, 2016, in Chicago. (Photo by Rob Grabowski/Invision/AP)

Note — Sorry to CSY followers.  I’ve been neglecting you.  I’ll be getting back on track next week with more new content.  In the interim, here’s something published at my Forbes site recently.  Have a great weekend. -Pete

These are heady days for American cities. They’re almost universally enjoying a renaissance of renewed attention, with growing numbers of young, educated workers increasingly choosing the urban lifestyle. Cities are adapting to accommodate the newcomers — new amenities, new infrastructure, new housing.

For the oldest American cities, the rebound is great news. But most will never be what they used to be.

Most people intuitively understand the economic underpinnings of urban decline, and the economic advantages that have led to their rebound. The loss of manufacturing destroyed the economic base; the spread of globalization and the new economy has created new opportunity in cities. But far less well understood are the far-reaching cultural and social changes that impacted the demographic makeup of cities — and would have caused population loss, even without economic restructuring.

This first came to my attention nearly two years ago, in a piece by Alex Ihnen of Next STL, a blog about all things St. Louis:

“What portion of the city’s population decline was “inevitable” or attributable to demographic changes? How much was due to macroeconomic trends? How much may be the result of local policy? It seems nearly everyone believes that the city should seek to add residents, but how, where, why?

American families have changed dramatically over the past half century. The average household size in St. Louis in 1950 was 3.1 and in 2010, 2.2. With every other factor held constant, the decrease in city population would have been 248K or 29%. This means that with the same number of homes, the same number of apartments, and the same number of families as resided in the city in 1950, the decrease in average household size could account for 46% of the city’s population loss.

American homes have changed dramatically over the past half century. The average size of a new single-family home in 1950 was 983sf, and in 2010, 2,438. While this number overstates changes in a long urbanized area, there has certainly been a large increase in the average size of the single-family home in the city. This could be new construction, but is also the common two-family to one-family and four-family to two-family renovations.

If nothing else had changed, and families had simply become smaller, and lived in bigger homes, the city would have lost hundreds of thousands of residents. What this really points to is that even if the city, or select neighborhoods reach zero vacancy – zero vacant lots, zero vacant homes – at today’s density, the residential population will not return to 1950, or even 1970 levels.”

Jason Segedy, who writes at about Akron, Ohio, explored this even further:

“Think about what was going on around 1960. Take an older, industrial city, like Cleveland, Detroit, or St. Louis, that is “built out” – that is, nearly all of the residential property in the city is built at the maximum development density that it is zoned for, and the city has very little, if any, available land upon which to build new housing.

At the same time you have several extremely consequential demographic trends occurring all at the same time:

Rising divorce ratesRising age of first marriageRising life expectancyDeclining birth rates

These trends all began to emerge in the late 1950s, took deep root in the late 1960s, and continued virtually unabated up through the late-1990s.”

And then the kicker:

“Focus instead on the profound social trends which occurred between 1960 and 1990. Those involving:

Marriage (divorce and delayed marriage, resulting in more singles)
Health care (increased longevity, resulting in more widows and widowers)
Reproduction (the development of “The Pill” in 1960, and legalized abortion in 1973, resulting in less children).

The end result of these trends? A much smaller average household size.

So, if these older cities were unable to build more housing units, they were going to shrink to a significant degree, regardless of the crime rate, or school quality, or “white flight”, or any of the other common explanations for urban population loss.”

Yes. In many respects, population loss in older American cities was virtually inevitable.

To see if this theory had any merit, I pulled data on population and housing units for the ten largest cities in 1950 and those same cities in 2010. Eight of the ten largest cities in 1950 reached their population peak at that time. How did they fare? Let’s look at a couple of tables. First, the 1950 table (click to enlarge):

And now the 2010 table:

A quick analysis: in 1950, in the aftermath of twenty years of economic depression and world war, there was little housing construction. That led to cities with extremely low numbers of vacancies and high numbers of persons per unit (one note: the data here may slightly overstate household size because not everyone lives in a household. In this dataset people who live in institutional housing were lumped in). In 2010, the combination of fewer persons per unit and far more housing vacancies means that the eight cities that reached their peak 60 years ago could never regain that population unless they 1) significantly add units or 2) significantly increase household size. Indeed, the two cities that surpassed their 1950 population did increase the number of households; New York did it through increasing its density in in-demand areas, and Los Angeles did it through relying on its abundance of available land for housing construction.

As for the others? Three cities actually lost housing units between 1950 and 2010: Cleveland, Detroit and St. Louis. Three others managed negligible housing gains over the 60-year period, remaining virtually constant in their numbers of housing units: Baltimore, Chicago and Philadelphia. Washington, DC and Boston both added housing units, but, unlike perhaps New York and Los Angeles, their housing growth is a more recent phenomenon. Further research could bear that out.

What’s important to note is how changes in housing units and household size impacts a city’s population “ceiling”. If we were to assume all housing units in a city were filled at the average household size, what would be the city’s population? This table illustrates the impact:

New York’s and Los Angeles’ ceilings rose over the 60-year period. In 1950, New York’s ceiling was 8.1 million; in 2010 it was nearly 8.9 million. Los Angeles’ ceiling in 1950 was about 2 million; in 2010 it was over 4 million.

For the others, the ceiling dropped. The cities that managed negligible housing unit increases, Baltimore, Chicago and Philadelphia, have 2010 population ceilings slightly under the 1950 level. Washington, DC and Boston have lower 2010 ceilings as well, but recent housing growth may change that. But Cleveland, Detroit and St. Louis all have 2010 ceilings that are roughly half of their 1950 ceilings.

The way we live moved away from the way 20th century large cities were constructed. If a city was built out, or its housing stock deemed obsolete by buyers and renters, its population would fall irrespective of the economic climate. This could also have implications for newer cities that boomed over the last half century. As they reach their build-out limits (as their current zoning ordinances allow), and as their housing ages and becomes less appealing to the preferences of potential new residents, could societal factors make population loss inevitable there as well?

It could happen.

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