Welcome back to Critical Eye, Alexandra Lange's incisive, observant, curious, human- and street-friendly architecture column for Curbed. In this edition, Lange debunks the oft-cited statistic that 50 percent of the world's population lives in cities, and makes a case for why holding on to that number is harming our design discourse.

When startup accelerator Y Combinator announced its New Cities project in June, it came with a couple of footnotes. Number one was, "Two out of three people will live in cities by 2050."

In the center of the cover of the 2006 book The Endless City, published by the Urban Age Project at the London School of Economics and Deutsche Bank, is the statistic, "10% lived in cities in 1900, 50% is living in cities in 2007, 75% will be living in cities in 2050."

On the header of the TED Cities page, "More than half the world's population lives in cities."

Problem is, these numbers aren’t real. Or rather, without a radical disruption of United Nations data collection methods—the 50 percent number comes from a 2007 UN agency report—we will never know whether half the population, or two-thirds, lives in a city. Not now, and not in 2050.

Though the chaos of quantification of cities should make the 50-percent-urban statistic unusable, the larger question is what the number hides.

As Neil Brenner, a professor of urban theory at Harvard’s Graduate School of Design, has argued in a series of papers dating back to 2013, the national census bureaus on which the UN relies to supply population figures have radically different definitions of city. Some countries designate cities by pure population, some by employment conditions or density, others by how a region is governed.

The US Census Bureau, for example, defines "urbanized areas" as those containing 50,000 people or more and "urban clusters" as those containing between 2,500 and 50,000 people. The rest is rural, but that’s a lot of variation.

The papering over of these differences makes the 50 percent figure moot (maybe we are already at 70 percent) and suppresses what may be the more interesting question, about what makes cities different from each other, what makes their edges hard to trace, and their populations (Daytime or nighttime? Summer or winter?) hard to capture.

Worse, 50-percent-urban has become a shorthand that implies universal value without forcing technologists, journalists, and motivational speakers alike to explain why their project or story, in particular, is important. It is human nature to be more interested in a category when it includes you, and numbers are a popular rhetorical flourish, but 50-percent-urban actually makes study of the city less personal and elides necessary complexity.

I can think of a dozen other reasons, right in their own backyard, why a Silicon Valley incubator should be interested in the future of housing, transportation, regional planning, and workplace design. Why, then, must they go global? The future of one kind of city, in which people live densely and work in sprawl, is being written on their doorstep, and yet, the use of the statistic implies that they want to change a larger, less knotty idea of the city.

The image the statistic always calls to my mind is a drawing worthy of a J.G. Ballard cover: the earth from space, with half the landmass built to 20 stories on a Manhattanized grid, the other half green topography. Ballard, always way ahead, wrote a version of this maximum world city in his 1957 short story, "Build-Up" (also known as "The Concentration City").

In that story, a designer hunts for space in vain. There is no outside, nothing extra-urban or even intra-green. Rather, whether you travel up, down, or across, there is only building and grid, a doubled and circular network, above and below, that foreshadows the claustrophobic underground action in the Capitol in the final Hunger Games novel. There is no green half, no rural District, to escape to. The pastoral is past.

In Brenner and Christian Schmid’s 2013 article, "The ‘urban age’ in question," they also turn to science fiction for the origins of the apocalyptic urbanized planet, pointing to H.G. Wells, alongside biologist and planning pioneer Patrick Geddes and philosopher Oswald Spengler, as propagators of turn-of-the-century visions of a built-up future. Though these predictions have become more data-driven in the postwar era, the critiques of their accuracy began long ago.

Sociologist Louis Wirth, writing in 1937, already understood contemporary network theory, and the flows of ideas, goods, and capital across arbitrary urban boundaries:

"The degree to which the contemporary world may be said to be ‘urban’ is not fully or accurately measured by the proportion of the total population living in cities. The influences which cities exert upon the social life of man [sic] are greater than the ratio of the urban population would indicate, for the city is . . . the initiating and controlling center of economic, political, and cultural life that has drawn the most remote parts of the world into its orbit and woven diverse areas, peoples, and activities into a cosmos."In this quotation, Wirth is still supposing that the flow is all one-way: people in, ideas out, even if defining a city is impossible and counter-productive. But contemporary critique goes further.

In a dialogue in his forthcoming book Critique of Urbanization, Brenner asks, "What about the supposed ‘rural’ or ‘non-urban’ domain outside of the dense population centers? Are the planet’s ‘hinterlands’ really irrelevant now, due to depopulation, migration or ecological degradation? Our research suggests that, on the contrary, the non-city landscapes of the world remain quite fundamental, in operational terms, to providing various kinds of material and metabolic support for urban-industrial life."

Considering the District structure of the Hunger Games—the novels are set in a post-apocalyptic world in some unspecified future time—reveals another problem with the 50 percent urban myth. District 12, home of Katniss Everdeen, is a place out of time, its residents dressed in the clothes and performing the work of WPA-era Appalachians.

It is rural, in the sense that only the government buildings and Victors’ Village are made of stone, and raised more than a couple of stories. But its people are working for the Capitol, extracting coal so that the concentration city can be a place of leisure. But they are urbanized, in the sense that they are tied, by industry and the railroad, to the systems of urban life.

My Ballardian diagram doesn’t show the veins beneath the green, the networks of extraction—the theme of the Canadian pavilion at the 2016 Venice Biennale—that run below ostensibly untouched and out-of-touch lands. Brenner has pointed to NASA’s nighttime lights map, a photo of the world after dark in which cities and their sprawl shine bright, oceans and smaller settlements and the centers of Africa and Australia in the dark, as part of the problem. There are millions of people there in the dark, obviously, but we don’t see them, a neat metaphor for the super-majority of research going toward urban development, and away from the suburban, exurban, and rural.

Fifty percent of the world’s population isn’t living in a version of Manhattan.

The Canadian pavilion, directed by Pierre Belanger, a colleague of Brenner’s at the GSD, is only one recent attempt to redress this imbalance. MIT’s Center for Advanced Urbanism’s spring conference on "The Future of Suburbia" is another, though the center’s name alone suggests a search for territory beyond cities. Other research on phenomena from space junk to the Great Pacific Garbage Patch, on the routes of shipping containers and tourism patterns alike, also run counter to the idea of the not-city as blank, dark, wet, or unworthy of study due to its own planned obsolescence.

Though the chaos of quantification of cities should make the 50-percent-urban statistic unusable, the larger question is what the number hides. It hides the differences between cities like New York, where I now live, and Durham, North Carolina, where I grew up.

Shreve, Lamb, and Harmon were the architects of the tallest building in each for decades, but in Durham our single skyscraper only had to reach 17 stories. It was a 20 minute walk from our single-family detached house on a leafy, sidewalk-free urban street. (The building is now a 21c Museum Hotel.) When my husband first visited, he kept asking when we would get to the city. The answer was always, "We are in the city."

It hides urbanism happening in non-urban areas: picturesque New Urbanist "villages" and rural Main Streets saved by the weekend tourist trade, but also rural areas transformed by the wants of cities. The rural tends to be treated as a "black box," undifferentiated and unexamined, and, as Brenner says, "Like grains of sand moving through the bulbs of an hourglass, social, spatial and environmental change is assumed to happen simply through a redistribution of elements between unchanging units, urban and rural."

It hides the rapid growth of dense settlements created by war and displacement or the follow-the-jobs hollowing out of one rural area in favor of another, which sometimes creates two not-cities, one for the men, the other for women and children.

It hides the more elastic definition of density that might actually allow shorter cities to densify without sacrificing NIMBY-favorite "way of life." It’s not residential skyscrapers that most cities—even the boroughs of New York—need to improve public transportation and lower rents. It is rowhouses and courtyard apartments of four or five stories, the very urban typologies tourists like to visit in Brooklyn and Santa Monica. City is not equal to "Concentration City," and 50 percent of the world’s population isn’t living in a version of Manhattan.

Forced to stop using a readymade, attention-grabbing number as justification should force everyone to think harder about why cities are at the center of our design discourse. Why should everything good flow to the center? Why are we so ready to embrace Ballard’s apocalypse? An interest in cities should flow from an interest in people. But we would do better to watch them than an upward-trending statistic.