Flashback Saturday – City size, variety, and consumer surplus

Every weekend we dig into the archives. This post by Peter was originally published in June 2016.

In the 1990s, in the early years of the information technology revolution, economist Robert Solow famously commented that “you can see the computer age everywhere but in the productivity statistics.” Two decades on, that still rings true. Social life has been profoundly transformed by new technology: It has altered the way we communicate with friends and family, how we entertain ourselves, and even how we date.

When I read Douglas Adams’ Hitchhiker’s Guide to the Galaxy in the early 2000s, the titular device still seemed like a fantastical idea: a handheld device you could use to access information (much of it inaccurate or incomplete) on anything, from anywhere.

Now, we all have smartphones. But productivity growth has stubbornly failed to take off over this period. Does this mean that technological progress has failed to deliver?

Journalist Ezra Klein (Vox) recently reviewed the current debate over technological progress. One perspective he discusses is that the benefits of information and communication technologies (ICTs) have largely accrued to consumers rather than producers:

Measures of productivity are based on the sum total of goods and services the economy produces for sale. But many digital-era products are given away for free, and so never have an opportunity to show themselves in GDP statistics.

Take Google Maps. I have a crap sense of direction, so it’s no exaggeration to say Google Maps has changed my life. I would pay hundreds of dollars a year for the product. In practice, I pay nothing. In terms of its direct contribution to GDP, Google Maps boosts Google’s advertising business by feeding my data back to the company so they can target ads more effectively, and it probably boosts the amount of money I fork over to Verizon for my data plan. But that’s not worth hundreds of dollars to Google, or to the economy as a whole. The result is that GDP data might undercount the value of Google Maps in a way it didn’t undercount the value of, say, Garmin GPS devices.

As Klein goes on to observe, ICTs have transformed our leisure time more than our work time – in large part, by giving us many more choices about where to dine, what television shows to watch, and who to talk to.

Interestingly, what’s true for technology might also be true for cities. The conventional narrative about agglomeration economies – the economic benefits of scale and density – is that their main effect is to lift productivity. But, as Stu and I have discussed in the past, there’s an increasing body of evidence that suggests that agglomeration also has significant benefits for consumers.

In recent years, economists have used micro-data on household consumption patterns to build a much richer picture of the impact of city size and structure on consumption choices. In short, larger cities don’t always offer lower prices – as you’d expect if higher productivity made it cheaper to produce goods and services. But they do offer a much greater variety of goods and services, which in turn translates into higher wellbeing for households.

A 2015 paper by Jessie Handbury and David Weinstein uses barcode data on retail sales in 49 large US cities to analyse prices and product varieties. They find that:

There are approximately four times more types of grocery products available in New York [metro population 21 million] than in Des Moines [population 456,000].

Because people in larger cities tend to buy a wider range of goods, including more expensive products, a naïve comparison of average retail prices would suggest that larger cities are more expensive. But Handbury and Weinstein’s analysis shows that, after accounting for product variety, prices in large cities are no more expensive than smaller cities. If anything, they tend to be lower:

When we use the data to construct a theoretically rigorous price index that corrects for product, purchaser, and retailer heterogeneity and accounts for variety differences across locations, we find that the price level is actually lower in larger cities. Consumers spend less, on average, to get the same amount of consumption utility in larger cities.

Moreover, what’s true in grocery stores is also true in restaurants. In a 2012 paper, Nathan Schiff took a look at the impact of city size and population density on restaurant markets in 726 urban places in the US. His key finding is that:

For the 182 cities in the top quartile by land area of my data (mean population 331,000), a one standard deviation increase in log population is associated with a 57% increase in the count of unique cuisines. A one standard deviation decrease in log land area–which increases population density without changing the size of the population–is associated with a 10% increase in cuisine count, equivalent to increasing the percentage of the population with a college degree by one standard deviation and larger than the effect of increasing the ethnic population associated with each cuisine by one standard deviation.

In other words, cities that are larger or denser offer people more choices about where and what to eat. Density is especially crucial in large cities, as people generally don’t travel long distances to dine. (Incidentally, relatively open migration policies are also an important enabler of restaurant choice in cities, as migrants bring new cuisines with them.)

What does this mean for urban policy? I think there are two main lessons.

The first is that although agglomeration economies in production are important to long-run economic outcomes, we might be looking for the benefits of cities in the wrong places. They might not always appear in productivity statistics or price indices, but in the consumption choices that cities offer people. Measuring variety – and how people respond to it – is therefore crucial to understanding agglomeration economies.

The second is that conventional urban policy might be based on false premises. Ever since the “dark Satanic mills” of the Industrial Revolution, policymakers have assumed that cities are good for businesses but bad for people. Accordingly, they designed transport systems and planning policies that aimed to disperse the city and to separate people from their workplaces and from each other.

That made sense when cholera was a major cause of death, but it’s increasingly illogical in today’s world. Urban disamenities such as air quality, crime rates, and infectious diseases are all improving, and the evidence increasingly shows that the consumer choices offered by cities (and dense urban places) have benefits for households. In this context, policies that enable urbanisation are likely to have larger benefits than commonly assumed.

What do you think about the role of consumer choice in cities?

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