How We Create and Destroy Growth: A Nobel for Romer and Nordhaus

Occasionally, the Nobel Committee gives a prize which is unexpected, surprising, yet deft in how it points out underappreciated research. This year, they did no such thing. Both William Nordhaus and Paul Romer have been running favorites for years in my Nobel betting pool with friends at the Federal Reserve. The surprise, if anything, is that the prize went to both men together: Nordhaus is best known for his environmental economics, and Romer for his theory of “endogenous” growth.

On reflection, the connection between their work is obvious. But it is the connection that makes clear how inaccurate many of today’s headlines – “an economic prize for climate change” – really is. Because it is not the climate that both winners build on, but rather a more fundamental economic question: economic growth. Why are some places and times rich and others poor? And what is the impact of these differences? Adam Smith’s “The Wealth of Nations” is formally titled “An Inquiry into the Nature and Causes of the Wealth of Nations”, so these are certainly not new questions in economics. Yet the Classical economists did not have the same conception of economic growth that we have; they largely lived in a world of cycles, of ebbs and flows, with income per capita facing the constraint of agricultural land. Schumpeter, who certainly cared about growth, notes that Smith’s discussion of the “different progress of opulence in different nations” is “dry and uninspired”, perhaps only a “starting point of a sort of economic sociology that was never written.”

As each generation became richer than the one before it – at least in a handful of Western countries and Japan – economists began to search more deeply for the reason. Marx saw capital accumulation as the driver. Schumpeter certainly saw innovation (though not invention, as he always made clear) as important, though he had no formal theory. It was two models that appear during and soon after World War II – that of Harrod-Domar, and Solow-Swan-Tinbergen – which began to make real progress. In Harrod-Domar, economic output is a function of capital Y=f(K), nothing is produced without capital f(0)=0, the economy is constant returns to scale in capital df/dK=c, and the change in capital over time depends on what is saved from output minus what depreciates dK/dt=sY-zK, where z is the rate of depreciation. Put those assumptions together and you will see that growth, dY/dt=sc-z. Since c and z are fixed, the only way to grow is to crank up the savings rate, Soviet style. And no doubt, capital deepening has worked in many places.

Solow-type models push further. They let the economy be a function of “technology” A(t), the capital stock K(t), and labor L(t), where output Y(t)=K^a*(A(t)L(t))^(1-a) – that is, that production is constant returns to scale in capital and labor. Solow assumes capital depends on savings and depreciation as in Harrod-Domar, that labor grows at a constant rate n, and that “technology” grows at constant rate g. Solving this model gets you that the economy grows such that dY/dt=sy-k(n+z+g), and that output is exactly proportional to capital. You can therefore just run a regression: we observe the amount of labor and capital, and Solow shows that there is not enough growth in those factors to explain U.S. growth. Instead, growth seems to be largely driven by change in A(t), what Abramovitz called “the measure of our ignorance” but which we often call “technology” or “total factor productivity”.

Well, who can see that fact, as well as the massive corporate R&D facilities of the post-war era throwing out inventions like the transistor, and not think: surely the factors that drive A(t) are endogenous, meaning “from within”, to the profit-maximizing choices of firms? If firms produce technology, what stops other firms from replicating these ideas, a classic positive externality which would lead the rate of technology in a free market to be too low? And who can see the low level of convergence of poor country incomes to rich, and not think: there must be some barrier to the spread of A(t) around the world, since otherwise the return to capital must be extraordinary in places with access to great technology, really cheap labor, and little existing capital to combine with it. And another question: if technology – productivity itself! – is endogenous, then ought we consider not just the positive externality that spills over to other firms, but also the negative externality of pollution, especially climate change, that new technologies both induce and help fix? Finally, if we know how to incentivize new technology, and how growth harms the environment, what is the best way to mitigate the great environmental problem of our day, climate change, without stopping the wondrous increase in living standards growth keeps providing? It is precisely for helping answer these questions that Romer and Nordhaus won the Nobel.

Romer and Endogenous Growth

Let us start with Paul Romer. You know you have knocked your Ph.D. thesis out of the park when the great economics journalist David Warsh writes an entire book hailing your work as solving the oldest puzzle in economics. The two early Romer papers, published in 1986 and 1990, have each been cited more than 25,000 times, which is an absolutely extraordinary number by the standards of economics.

Romer’s achievement was writing a model where inventors spend money to produce inventions with increasing returns to scale, other firms use those inventions to produce goods, and a competitive Arrow-Debreu equilibrium still exists. If we had such a model, we could investigate what policies a government might wish to pursue if it wanted to induce firms to produce growth-enhancing inventions.

Let’s be more specific. First, innovation is increasing returns to scale because ideas are nonrival. If I double the amount of labor and capital, holding technology fixed, I double output, but if I double technology, labor, and capital, I more than double output. That is, give one person a hammer, and they can build, say, one staircase a day. Give two people two hammers, and they can build two staircases by just performing exactly the same tasks. But give two people two hammers, and teach them a more efficient way to combine nail and wood, and they will be able to build more than two staircases. Second, if capital and labor are constant returns to scale and are paid their marginal product in a competitive equilibrium, then there is no output left to pay inventors anything for their ideas. That is, it is not tough to model in partial equilibrium the idea of nonrival ideas, and indeed the realization that a single invention improves productivity for all is also an old one: as Thomas Jefferson wrote in 1813, “[h]e who receives an idea from me, receives instruction himself without lessening mine; as he who lights his taper at mine, receives light without darkening me.” The difficulty is figuring out how to get these positive spillovers yet still have “prices” or some sort of rent for the invention. Otherwise, why would anyone pursue costly invention?

We also need to ensure that growth is not too fast. There is a stock of existing technology in the world. I use that technology to create new innovations which grow the economy. With more people over time and more innovations over time, you may expect the growth rate to be higher in bigger and more technologically advanced societies. It is in part, as Michael Kremer points out in his One Million B.C. paper. Nonetheless, the rate of growth is not asymptotically increasing by any stretch (see, e.g., Ben Jones on this point). Indeed, growth is nearly constant, abstracting from the business cycle, in the United States, despite a big growth in population and the stock of existing technology.

Romer’s first attempt at endogenous growth was based on his thesis and published in the JPE in 1986. Here, he adds “learning by doing” to Solow: technology is a function of the capital stock A(t)=bK(t). As each firm uses capital, they generate learning which spills over to other firms. Even if population is constant, with appropriate assumptions on production functions and capital depreciation, capital, output, and technology grow over time. There is a problem here, however, and one that is common to any model based on learning-by-doing which partially spills over to other firms. As Dasgupta and Stiglitz point out, if there is learning-by-doing which only partially spills over, the industry is a natural monopoly. And even if it starts competitively, as I learn more than you, dynamically I can produce more efficiently, lower my prices, and take market share from you. A decentralized competitive equilibrium with endogenous technological growth is unsustainable!

Back to the drawing board, then. We want firms to intentionally produce technology in a competitive market as they would other goods. We want technology to be nonrival. And we want technology production to lead to growth. Learning-by-doing allows technology to spill over, but would simply lead to a monopoly producer. Pure constant-returns-to-scale competitive production, where technology is just an input like capital produced with a “nonconvexity” – only the initial inventor pays the fixed cost of invention – means that there is no output left to pay for invention once other factors get their marginal product. A natural idea, well known to Arrow 1962 and others, emerges: we need some source of market power for inventors.

Romer’s insight is that inventions are nonrival, yes, but they are also partially excludable, via secrecy, patents, or other means. In his blockbuster 1990 JPE Endogenous Technological Change, he lets inventions be given an infinite patent, but also be partially substitutable by other inventions, constraining price (this is just a Spence-style monopolistic competition model). The more inventions there are, the more efficiently final goods can be made. Future researchers can use present technology as an input to their invention for free. Invention is thus partially excludable in the sense that my exact invention is “protected” from competition, but also spills over to other researchers by making it easier for them to invent other things. Inventions are therefore neither public nor private goods, and also not “club goods” (nonrival but excludable) since inventors cannot exclude future inventors from using their good idea to motivate more invention. Since there is free entry into invention, the infinite stream of monopoly rents from inventions is exactly equal to their opportunity cost.

From the perspective of final goods producers, there are just technologies I can license as inputs, which I then use in a constant returns to scale way to produce goods, as in Solow. Every factor is paid its marginal product, but inventions are sold for more than their marginal cost due to monopolistic excludability from secrecy or patents. The model is general equilibrium, and gives a ton of insight about policy: for instance, if you subsidize capital goods, do you get more or less growth? In Romer (1986), where all growth is learning-by-doing, cheaper capital means more learning means more growth. In Romer (1990), capital subsidies can be counterproductive!

There are some issues to be worked out: the Romer models still have “scale effects” where growth is not constant, roughly true in the modern world, despite changes in population and the stock of technology (see Chad Jones’ 1995 and 1999 papers). The neo-Schumpeterian models of Aghion-Howitt and Grossman-Helpman add the important idea that new inventions don’t just add to the stock of knowledge, but also make old inventions less valuable. And really critically, the idea that institutions and not just economic fundamentals affect growth – meaning laws, culture, and so on – is a massive field of research at present. But it was Romer who first cracked the nut of how to model invention in general equilibrium, and I am unaware of any later model which solves this problem in a more satisfying way.

Nordhaus and the Economic Solution to Pollution

So we have, with Romer, a general equilibrium model for thinking about why people produce new technology. The connection with Nordhaus comes in a problem that is both caused by, and potentially solved by, growth. In 2018, even an ignoramus knows the terms “climate change” and “global warming”. This was not at all the case when William Nordhaus began thinking about how the economy and the environment interrelate in the early 1970s.

Growth as a policy goal was fairly unobjectionable as a policy goal in 1960: indeed, a greater capability of making goods, and of making war, seemed a necessity for both the Free and Soviet worlds. But by the early 1970s, environmental concerns arose. The Club of Rome warned that we were going to run out of resources if we continued to use them so unsustainably: resources are of course finite, and there are therefore “limits to growth”. Beyond just running out of resources, growth could also be harmful because of negative externalities on the environment, particularly the newfangled idea of global warming an MIT report warned about in 1970.

Nordhaus treated those ideas both seriously and skeptically. In a 1974 AER P&P, he notes that technological progress or adequate factor substitution allow us to avoid “limits to growth”. To put it simply, whales are limited in supply, and hence whale oil is as well, yet we light many more rooms than we did in 1870 due to new technologies and substitutes for whale oil. Despite this skepticism, Nordhaus does show concern for the externalities of growth on global warming, giving a back-of-the-envelope calculation that along a projected Solow-type growth path, the amount of carbon in the atmosphere will reach a dangerous 487ppm by 2030, surprisingly close to our current estimates. In a contemporaneous essay with Tobin, and in a review of an environmentalist’s “system dynamics” predictions of future economic collapse, Nordhaus reaches a similar conclusion: substitutable factors mean that running out of resources is not a huge concern, but rather the exact opposite, that we will have access to and use too many polluting resources, should worry us. That is tremendous foresight for someone writing in 1974!

Before turning back to climate change, can we celebrate again the success of economics against the Club of Rome ridiculousness? There were widespread predictions, from very serious people, that growth would not just slow but reverse by the end of the 1980s due to “unsustainable” resource use. Instead, GDP per capita has nearly doubled since 1990, with the most critical change coming for the very poorest. There would have been no greater disaster for the twentieth century than had we attempted to slow the progress and diffusion of technology, in agriculture, manufacturing and services alike, in order to follow the nonsense economics being promulgated by prominent biologists and environmental scientists.

Now, being wrong once is no guarantee of being wrong again, and the environmentalists appear quite right about climate change. So it is again a feather in the cap of Nordhaus to both be skeptical of economic nonsense, and also sound the alarm about true environmental problems where economics has something to contribute. As Nordhaus writes, “to dismiss today’s ecological concerns out of hand would be reckless. Because boys have mistakenly cried “wolf’ in the past does not mean that the woods are safe.”

Just as we can refute Club of Rome worries with serious economics, so too can we study climate change. The economy affects the climate, and the climate effects the economy. What we need an integrated model to assess how economic activity, including growth, affects CO2 production and therefore climate change, allowing us to back out the appropriate Pigouvian carbon tax. This is precisely what Nordhaus did with his two celebrated “Integrated Assessment Models”, which built on his earlier simplified models (e.g., 1975’s Can We Control Carbon Dioxide?). These models have Solow-type endogenous savings, and make precise the tradeoffs of lower economic growth against lower climate change, as well as making clear the critical importance of the social discount rate and the micro-estimates of the cost of adjustment to climate change.

The latter goes well beyond the science of climate change holding the world constant: the Netherlands, in a climate sense, should be underwater, but they use dikes to restraint the ocean. Likewise, the cost of adjusting to an increase in temperature is something to be estimated empirically. Nordhaus takes climate change very seriously, but he is much less concerned about the need for immediate action than the famous Stern report, which takes fairly extreme positions about the discount rate (1000 generations in the future are weighed the same as us, in Stern) and the costs of adjustment.

Consider the following “optimal path” for carbon from Nordhaus’ most recent run of the model, where the blue line is his optimum.

Note that he permits much more carbon than Stern or a policy which mandates temperatures stay below a 2.5 C rise forever. The reason is the costs to growth in the short term are high: the world is still very poor in many places! There was a vitriolic debate following the Stern report about who was correct: whether the appropriate social discount rate is zero or something higher is a quasi-philosophical debate going back to Ramsey (1928). But you can see here how important the calibration is.

There are other minor points of disagreement between Nordhaus and Stern, and my sense is that there has been some, though not full, convergence if their beliefs about optimal policy. But there is no disagreement whatsoever between the economic and environmental community that the appropriate way to estimate the optimal response to climate change is via an explicit model incorporating some sort of endogeneity of economic reaction to climate policy. The power of the model is that we can be extremely clear about what points of disagreement remain, and we can examine the sensitivity of optimal policy to factors like climate “tipping points”.

There is one other issue: in Nordhaus’ IAMs, and in Stern, you limit climate change by imposing cap and trade or carbon taxes. But carbon harms cross borders. How do you stop free riding? Nordhaus, in a 2015 AER, shows theoretically that there is no way to generate optimal climate abatement without sanctions for non-participants, but that relatively small trade penalties work quite well. This is precisely what Emmanuel Macron is currently proposing!

Let’s wrap up by linking Nordhaus even more tightly back to Romer. It should be noted that Nordhaus was very interested in the idea of pure endogenous growth, as distinct from any environmental concerns, from the very start of his career. His thesis was on the topic (leading to a proto-endogenous growth paper in the AER P&P in 1969), and he wrote a skeptical piece in the QJE in 1973 about the then-leading theories of what factors induce certain types of innovation (objections which I think have been fixed by Acemoglu 2002). Like Romer, Nordhaus has long worried that inventors do not receive enough of the return to their invention, and that we measure innovation poorly – see his classic NBER chapter on inventions in lighting, and his attempt to estimate how much of how much of society’s output goes to innovators.

The connection between the very frontier of endogenous growth models, and environmental IAMs, has not gone unnoticed by other scholars. Nordhaus IAMs tend to have limited incorporation of endogenous innovation in dirty or clean sectors. But a fantastic paper by Acemoglu, Aghion, Bursztyn, and Hemous combines endogenous technical change with Nordhaus-type climate modeling to suggest a middle ground between Stern and Nordhaus: use subsidies to get green energy close to the technological frontier, then use taxes once their distortion is relatively limited because a good green substitute exists. Indeed, since this paper first started floating around 8 or so years ago, massive subsidies to green energy sources like solar by many countries have indeed made the “cost” of stopping climate change much lower than if we’d relied solely on taxes, since now production of very low cost solar, and mass market electric cars, is in fact economically viable.

It may indeed be possible to solve climate change – what Stern called “the greatest market failure” man has ever seen – by changing the incentives for green innovation, rather than just by making economic growth more expensive by taxing carbon. Going beyond just solving the problem of climate change, to solving it in a way that minimizes economic harm, is a hell of an accomplishment, and more than worthy of the Nobel prizes Romer and Nordhaus won for showing us this path!

Some Further Reading

In my PhD class on innovation, the handout I give on the very first day introduces Romer’s work and why non-mathematical models of endogenous innovation mislead. Paul Romer himself has a nice essay on climate optimism, and the extent to which endogenous invention matters for how we stop global warming. On why anyone signs climate change abatement agreements, instead of just free riding, see the clever incomplete contracts insight of Battaglini and Harstad. Romer has also been greatly interested in the policy of “high-growth” places, pushing the idea of Charter Cities. Charter Cities involve Hong Kong like exclaves of a developing country where the institutions and legal systems are farmed out to a more stable nation. Totally reasonable, but in fact quite controversial: a charter city proposal in Madagascar led to a coup, and I can easily imagine that the Charter City controversy delayed Romer’s well-deserved Nobel laurel. The New York Times points out that Nordhaus’ brother helped write the Clean Air Act of 1970. Finally, as is always true with the Nobel, the official scientific summary is lucid and deep in its exploration of the two winners’ work.

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“The First Patent Litigation Explosion,” C. Beauchamp (2016)

There has been a tremendous rise in patent litigation in the past decade (Bessen and Meurer 2005). Many of these lawsuits have come from “non-practicing entities” – also known as patent trolls – who use their patents to sue even as they produce no products themselves. These lawsuits are often targeted at end-users rather than directly infringing manufacturers, supposedly on the grounds that end-users are less able to defend themselves (see my coauthor Erik Hovenkamp on this point). For those who feel the patent system provides too many rights to patent-holders, to the detriment of societal welfare, problems like these are case in point.

But are these worries novel? The economics of innovation and entrepreneurship is, like much of economics, one where history proves illuminating. Nearly everything that we think is new has happened before. Fights over the use of IP to collude by incumbents? See Lampe and Moser 2010 JEH. The importance of venture capital to local ecosystems? In the late 19th century, this was true in the boomtown of Cleveland, as Lamoreaux and her coauthors showed in a 2006 C&S (as to why Cleveland declines as an innovative center, they have a nice paper on that topic as well). The role of patent brokers and other intermediaries? These existed in the 19th century! Open source invention in the early days of a new industry? Tales from the rise of the porter style of beer in the 18th century are not terribly different from the Homebrew Computer Club that led to the personal computer industry. Tradeoffs between secrecy, patenting, and alternative forms of protection? My colleague Alberto Galasso shows that this goes back to Renaissance Italy!

Given these examples, it should not be surprising that the recent boom in patent litigation is a historical rerun. Christopher Beauchamp of Brooklyn Law School, in a 2016 article in the Yale Law Journal, shows that all of the problems with patent litigation mentioned above are not new: indeed, the true heyday of patent litigation was not the 2010s, but the late 1800s! Knowing the number of lawsuits filed, not just the number litigated to decision, requires painstaking archival research. Having dug up these old archives, Beauchamp begins with a striking fact: the Southern District of New York alone had as many total patent lawsuits filed in 1880 as any district in 2010, and on a per patent basis had an order of magnitude more lawsuits. These legal battles were often virulent. For instance, Charles Goodyear’s brother held patents for the use of rubber in dentistry, using attractive young women to find dentists using the technique without a license. The aggressive legal strategy ended only when the Vulcanite Company’s hard-charging treasurer was murdered in San Francisco by a desperate dentist!

These lawsuits were not merely battles between the Apples and Samsungs of the day, but often involved lawsuits demanding small license payments from legally unsophisticated users. Iowa Senator Samuel Kirkwood: patentholders “say to each [farmer], ‘Sir, pay me so much a mile or so much a rod for the wire…or you must go to Des Moines…and defend a suit to be brought against you, the cost of which and the fees in which will in themselves be more than I demand of you…[O]ur people are paying day by day $10, $15, $20, when they do not know a particle more whether they owe the man a dollar or a cent…but paying the money just because it is cheaper to do it than to defend a suit.” Some of these lawsuits were legitimate, but many were making claims far beyond the scope of what a court would consider infringement, just as in the case of patent troll lawsuits today. Also like today, farmers and industry associations formed joint litigation pools to challenge what they considered weak patents.

In an echo of complaints about abuse of the legal system and differential costs of filing lawsuits compared to defending oneself, consider Minnesota Senator William Windom’s comments: “[B]y the authority of the United States you may go to the capital of a State and for a claim of $5 each you may send the United States marshal to a thousand men, or ten thousand…and compel them to travel hundreds of miles to defend against your claim, or, as more frequently occurs, to pay an unjust demand as the cheapest way of meeting it.” Precisely the same complaint applies to modern patent battles.

A question of great relevance to our modern patent litigation debate therefore is immediate: Why did these scattershot individual lawsuits eventually fade away in the late 1800s? Beauchamp is equivocal here, but notes that judicial hostility toward the approach may have decreased win rates, and hence the incentive to file against small, weak defendants. Further, the rise of the modern corporation (see Alfred Chandler’s Scale and Scope) in the late 19th century changed the necessity of sublicensing inventions to local ligitating attorneys, rather that just suing large infringing manufacturers directly.

Of course, not everything historic is a mirror of the present. A major source of patent litigation in the mid-1800s involved patent reissues. Essentially, a patent would be granted with weak scope. An industry would rise up using related non-infringing technology. A sophisticated corporation would buy the initial patent, then file for a “reissue” which expanded the scope of the patent to cover many technologies then in use. Just as “submarine” patents, held secretly in application while an industry grows, are a major problem recently, patent reissues led to frequent 19th century complaints, until changes in jurisprudence in the late 1800s led to greatly decreased deference to the reissued patent.

What does this history tell us about modern innovation policy? As Beauchamp discusses, “[t]o a modern observer, the content of the earlier legal and regulatory reactions can seem strikingly familiar. Many of the measures now proposed or attempted as solutions for the ills of modern patent litigation were proposed or attempted in the nineteenth century as well.” To the extent we are worried about how to stop “patent trolls” from enforcing weak patents against unsophisticated end-users, we ought look at how our 19th century forebears handled the weak barbed wire and well patents filed against small-town farmers. With the (often economically-illiterate) rise of the “Hipster Antitrust” ideas of Lina Khan and her compatriots, will the intersection of patent and antitrust law move from today’s “technocratic air” – Beauchamp’s phrase – to the more political battleground of the 19th century? And indeed, for patent skeptics like myself, how are we to reconcile the litigious era of patenting of 1850-1880 with the undisputed fact that this period was dead in the heart of the Second Industrial Revolution, the incredible rise of electricity and modern chemicals inventions that made the modern world?

Full article is in Yale Law Journal, Feb. 2016.

“The Development Effects of the Extractive Colonial Economy,” M. Dell & B. Olken (2017)

A good rule of thumb is that you will want to read any working paper Melissa Dell puts out. Her main interest is the long-run path-dependent effect of historical institutions, with rigorous quantitative investigation of the subtle conditionality of the past. For instance, in her earlier work on Peru (Econometrica, 2010), mine slavery in the colonial era led to fewer hacienda style plantations at the end of the era, which led to less political power without those large landholders in the early democratic era, which led to fewer public goods throughout the 20th century, which led to less education and income today in eras that used to have mine slavery. One way to read this is that local inequality is the past may, through political institutions, be a good thing today! History is not as simple as “inequality is the past causes bad outcomes today” or “extractive institutions in the past cause bad outcomes today” or “colonial economic distortions cause bad outcomes today”. But, contra the branch of historians that don’t like to assign causality to any single factor in any given situation, we don’t need to entirely punt on the effects of specific policies in specific places if we apply careful statistical and theoretical analysis.

Dell’s new paper looks at the cultuurstelsel, a policy the Dutch imposed on Java in the mid-19th century. Essentially, the Netherlands was broke and Java was suitable for sugar, so the Dutch required villages in certain regions to use huge portions of their arable land, and labor effort, to produce sugar for export. They built roads and some rail, as well as sugar factories (now generally long gone), as part of this effort, and the land used for sugar production generally became public village land controlled at the behest of local leaders. This was back in the mid-1800s, so surely it shouldn’t affect anything of substance today?

But it did! Take a look at villages near the old sugar plantations, or that were forced to plant sugar, and you’ll find higher incomes, higher education levels, high school attendance rates even back in the late colonial era, higher population densities, and more workers today in retail and manufacturing. Dell and Olken did some wild data matching using a great database of geographic names collected by the US government to match the historic villages where these sugar plants, and these labor requirements, were located with modern village and town locations. They then constructed “placebo” factories – locations along coastal rivers in sugar growing regions with appropriate topography where a plant could have been located but wasn’t. In particular, as in the famous Salop circle, you won’t locate a factory too close to an existing one, but there are many counterfactual equilibria where we just shift all the factories one way or the other. By comparing the predicted effect of distance from the real factory on outcomes today with the predicted effect of distance from the huge number of hypothetical factories, you can isolate the historic local influence of the real factory from other local features which can’t be controlled for.

Consumption right next to old, long-destroyed factories is 14% higher than even five kilometers away, education is 1.25 years longer on average, electrification, road, and rail density are all substantially higher, and industrial production upstream and downstream from sugar (e.g., farm machinery upstream, and processed foods downstream) are also much more likely to be located in villages with historic factories even if there is no sugar production anymore in that region!

It’s not just the factory and Dutch investments that matter, however. Consider the villages, up to 10 kilometers away, which were forced to grow the raw cane. Their elites took private land for this purpose, and land inequality remains higher in villages that were forced to grow cane compared to villages right next door that were outside the Dutch-imposed boundary. But this public land permitted surplus extraction in an agricultural society which could be used for public goods, like schooling, which would later become important! These villages were much more likely to have schools especially before the 1970s, when public schooling in Indonesia was limited, and today are higher density, richer, more educated, and less agricultural than villages nearby which weren’t forced to grow cane. This all has shades of the long debate on “forward linkages” in agricultural societies, where it is hypothesized that agricultural surplus benefits industrialization by providing the surplus necessary for education and capital to be purchased; see this nice paper by Sam Marden showing linkages of this sort in post-Mao China.

Are you surprised by these results? They fascinate me, honestly. Think through the logic: forced labor (in the surrounding villages) and extractive capital (rail and factories built solely to export a crop in little use domestically) both have positive long-run local effects! They do so by affecting institutions – whether villages have the ability to produce public goods like education – and by affecting incentives – the production of capital used up- and downstream. One can easily imagine cases where forced labor and extractive capital have negative long-run effects, and we have great papers by Daron Acemoglu, Nathan Nunn, Sara Lowes and others on precisely this point. But it is also very easy for societies to get trapped in bad path dependent equilibria, for which outside intervention, even ethically shameful ones, can (perhaps inadvertently) cause useful shifts in incentives and institutions! I recall a visit to Babeldaob, the main island in Palau. During the Japanese colonial period, the island was heavily industrialized as part of Japan’s war machine. These factories were destroyed by the Allies in World War 2. Yet despite their extractive history, a local told me many on the island believe that the industrial development of the region was permanently harmed when those factories were damaged. It seems a bit crazy to mourn the loss of polluting, extractive plants whose whole purpose was to serve a colonial master, but the Palauan may have had some wisdom after all!

2017 Working Paper is here (no RePEc IDEAS version). For more on sugar and institutions, I highly recommend Christian Dippel, Avner Greif and Dan Trefler’s recent paper on Caribbean sugar. The price of sugar fell enormously in the late 19th century, yet wages on islands which lost the ability to productively export sugar rose. Why? Planters in places like Barbados had so much money from their sugar exports that they could manipulate local governance and the police, while planters in places like the Virgin Islands became too poor to do the same. This decreased labor coercion, permitting workers on sugar plantations to work small plots or move to other industries, raising wages in the end. I continue to await Suresh Naidu’s book on labor coercion – it is astounding the extent to which labor markets were distorted historically (see, e.g., Eric Foner on Reconstruction), and in some cases still today, by legal and extralegal restrictions on how workers could move on up.

“Scale versus Scope in the Diffusion of New Technology,” D. Gross (2016)

I am spending part of the fall down at Duke University visiting the well-known group of innovation folks at Fuqua and co-teaching a PhD innovation course with Wes Cohen, who you may know via his work on Absorptive Capacity (EJ, 1989), the “Carnegie Mellon” survey of inventors with Dick Nelson and John Walsh, and his cost sharing R&D argument (article gated) with Steven Klepper. Last week, the class went over a number of papers on the diffusion of technology over space and time, a topic of supreme importance in the economics of innovation.

There are some canonical ideas in diffusion. First, cumulative adoption on the extensive margin – are you or your firm using technology X – follows an S-curve, rising slowly, then rapidly, then slowly again until peak adoption is reached. This fact is known to economists thanks to Griliches 1957 but the idea was initially developed by social psychologists and sociologists. Second, there are massive gaps in the ability of firms and nations to adopt and quickly diffuse new technologies – Diego Comin and Burt Hobijn have written a great deal on this problem. Third, the reason why technologies are slow to adopt depends on many factors, including social learning (e.g., Conley and Udry on pineapple growing in Ghana), pure epidemic-style network spread (the “Bass model”), capital replacement, “appropriate technologies” arriving once conditions are appropriate, and many more.

One that is very much underrated, however, is that technologies diffuse because they and their complements change over time. Dan Gross from HBS, another innovation scholar who likes delving into history, has a great example: the early tractor. The tractor was, in theory, invented in the 1800s, but was uneconomical and not terribly useful. With an invention by Ford in the 1910s, tractors began to spread, particularly among the US wheat belt. The tractor eventually spreads to the rest of the Midwest in the late 1920s and 1930s. A back-of-the-envelope calculation by Gross suggests the latter diffusion saved something like 10% of agricultural labor in the areas where it spread. Why, then, was there such a lag in many states?

There are many hypotheses in the literature: binding financial constraints, differences in farm sizes that make tractors feasible in one area and not another, geographic spread via social learning, and so on. Gross’ explanation is much more natural: early tractors could not work with crops like corn, and it wasn’t until after a general purpose tractor was invented in the 1920s that complementary technologies were created allowing the tractor to be used on a wide variety of farms. The charts are wholly convincing on this point: tractor diffusion time is very much linked to dominant crop, the early tractor “skipped” geographies where were inappropriate, and farms in areas where tractors diffused late nonetheless had substantial diffusion of automobiles, suggesting capital constraints were not the binding factor.

But this leaves one more question: why didn’t someone modify the tractor to make it general purpose in the first place? Gross gives a toy model that elucidates the reason quite well. Assume there is a large firm that can innovate on a technology, and can either develop a general purpose or applied versions of the technology. Assume that there is a fringe of firms that can develop complementary technology to the general purpose one (a corn harvester, for instance). If the large firm is constrained in how much innovation it can perform at any one time, it will first work on the project with highest return. If the large firm could appropriate the rents earned by complements – say, via a licensing fee – it would like to do so, but that licensing fee would decrease the incentive to develop the complements in the first place. Hence the large firm may first work on direct applications where it can capture a larger share of rents. This will imply that technology diffuses slowly first because applications are very specialized, then only as the high-return specialties have all been developed will it become worthwhile to shift researchers over to the general purpose technology. The general purpose technology will induce complements and hence rapid diffusion. As adoption becomes widespread, the rate of adoption slows down again. That is, the S-curve is merely an artifact of differing incentives to change the scope of an invention. Much more convincing that reliance on behavioral biases!

2016 Working Paper (RePEc IDEAS version). I have a paper with Jorge Lemus at Illinois on the problem of incentivizing firms to work on the right type of project, and the implications thereof. We didn’t think in terms of product diffusion, but the incentive to create general purpose technologies can absolutely be added straight into a model of that type.

Douglass North, An Economist’s Historian

Sad news today arrives, as we hear that Douglass North has passed away, living only just longer than his two great compatriots in Cliometrics (Robert Fogel) and New Institutional Economics (Ronald Coase). There will be many lovely pieces today, I’m sure, on North’s qualitative and empirical exploration of the rise of institutions as solutions to agency and transaction cost problems, a series of ideas that continues to be enormously influential. No economist today denies the importance of institutions. If economics is the study of the aggregation of rational choice under constraints, as it is sometimes thought to be, then North focused our mind on the origin of the constraints rather the choice or its aggregation. Why do states develop? Why do guilds, and trade laws, and merchant organizations, and courts, appear, and when? How does organizational persistence negatively affect the economy over time, a question pursued at great length by Daron Acemoglu and his coauthors? All important questions, and it is not clear that there are better answers than the ones North provided.

But North was not, first and foremost, a historian. His PhD is in economics, and even late in life he continued to apply the very most cutting edge economic tools to his studies of institutions. I want to discuss today a beautiful piece of his, “The Role of Institutions in the Revival of Trade”, written jointly with Barry Weingast and Paul Milgrom in 1990. This is one of the fundamental papers in “Analytic Narratives”, as it would later be called, a school which applied formal economic theory to historical questions; I have previously discussed here a series of papers by Avner Greif and his coauthors which are the canonical examples.

Here is the essential idea. In the late middle ages, long distance trade, particularly at “Fairs” held in specific places at specific times, arose again in Western Europe. Agency problems must have been severe: how do you keep people from cheating you, from stealing, from selling defective goods, or from reneging on granted credit? A harmonized body of rules, the Merchant Law, appeared across many parts of Western Europe, with local courts granting judgments on the basis of this Law. In the absence of nation-states, someone with a negative judgment could simply leave the local city where the verdict was given. The threat of not being able to sell in the future may have been sufficient to keep merchants fair, but if the threat of future lost business was the only credible punishment, then why were laws and courts needed at all? Surely merchants could simply let it be known that Johann or Giuseppe is a cheat, and that one shouldn’t deal with them? There is a puzzle here, then: it appears that the set of punishments the Merchant Law could give are identical to the set of “punishments” one receives for having a bad reputation, so why then did anybody bother with courts and formal rules? In terms of modern theory, if relational contracts and formal contracts can offer identical punishments for deviating from cooperation, and formal contracts are costly, then why doesn’t everyone simply rely on relational contracts?

Milgrom, North and Weingast consider a simple repeated Prisoner’s Dilemma. Two agents with a sufficiently high discount rate can sustain cooperation in a Prisoner’s Dilemma using tit-for-tat: if you cheat me today, I cheat you tomorrow. Of course, the Folk Theorem tells us that cooperation can be sustained using potentially more complex punishment strategies in infinitely repeated games with any number of players, although a fundamental idea in the repeated games literature is that it may be necessary to punish people who do not themselves punish when they are meant to do so. In a repeated prisoner’s dilemma with an arbitrary number of players who randomly match each period, cooperation can be sustained in a simple way: you cheat anyone you match with if they cheated their previous trading partner and their previous trading partner did not themselves cheat their partner two rounds ago, and otherwise cooperate.

The trick, though, is that you need to know the two-periods-back history of your current trading partner and their last trading partner. Particularly with long-distance trade, you might frequently encounter traders you don’t know even indirectly. Imagine that every period you trade with someone you have never met before, and who you will never meet again (the “Townsend turnpike”, with two infinite lines of traders moving in opposite directions), and imagine that you do not know the trading history of anyone you match with. In this incomplete information game, there is no punishment for cheating: you cheat the person you match with today, and no one you meet with tomorrow will ever directly or indirectly learn about this. Hence cooperation is not sustained.

What we need, then, is an institution that first collects a sufficient statistic for the honesty of traders you might deal with, that incentivizes merchants to bother to check this sufficient statistic and punish people who have cheated, and that encourages people to report if they have been cheated even if this reporting is personally costly. That is, “institutions must be designed both to keep the traders adequately informed of their responsibilities and to motivate them to do their duties.”

Consider an institution LM. When you are matched with a trading partner, you can query LM at cost Q to find out if there are any “unpaid judgments” against your trading partner, and this query is common knowledge to you and your partner. You and your partner then play a trading game which is a Prisoner’s Dilemma. After trading, and only if you paid the query cost Q, when you have been cheated you can pay another cost C to take your trading partner to trial. If your partner cheated you in the Prisoner’s Dilemma and you took them to trial, you win a judgment penalty of J which the cheater can either voluntarily pay you at cost c(J) or which the cheater can ignore. If the cheater doesn’t pay a judgment, LM lists them as having “unpaid judgments”.

Milgrom, North and Weingast show that, under certain conditions, the following is an equilibrium where everyone always cooperates: if you have no unpaid judgments, you always query LM. If no one queries LM, or if there are unpaid judgments against your trading partner, you defect in the Prisoner’s Dilemma, else you cooperate. If both parties queried LM and only one defects in the Prisoner’s Dilemma, the other trader pays cost C and takes the cheater to the LM for judgment. The conditions needed for this to be an equilibrium are that penalties for cheating are high enough, but not so high that cheaters prefer to retire to the countryside rather than pay them, and that the cost of querying LM is not too high. Note how the LM equilibrium encourages anyone to pay the personal cost of checking their trading partner’s history: if you don’t check, then you can’t go to LM for judgment if you are cheated, hence you will definitely be cheated. The LM also encourages people to pay the personal cost of putting a cheater on trial, because that is the only way to get a judgment decision, and that judgment is actually paid in equilibrium. Relying on reputation in the absence of an institution may not work if communicating reputation of someone who cheated you is personally costly: if you need to print up posters that Giuseppe cheated you, but can otherwise get no money back from Giuseppe, you are simply “throwing good money after bad” and won’t bother. The LM institution provides you an incentive to narc on the cheats.

Note also that in equilibrium, the only cost of the system is the cost of querying, since no one cheats. That is, in the sense of transactions costs, the Law Merchant may be a very low-cost institution: it generates cooperation even though only one piece of information, the existence of unpaid judgments, needs to be aggregated and communicated, and it generates cooperation among a large set of traders that never personally interact by using a single centralized “record-keeper”. Any system that induces cooperation must, at a minimum, inform a player whether their partner has cheated in the past. The Law Merchant system does this with no other costs in equilibrium, since in equilibrium, no one cheats, no one goes for judgment, and no resources are destroyed paying fines.

That historical institutions develop largely to limit transactions costs is a major theme in North’s work, and this paper is a beautiful, highly formal, explication of that broad Coasean idea. Our motivating puzzle – why use formal institutions when reputation provides precisely the same potential for punishment? – can be answered simply by noting that reputation requires information, and the cost-minimizing incentive-compatible way to aggregate and share that information may require an institution. The Law Merchant arises not because we need a way to punish offenders, since in the absence of the nation-state the Law Merchant offers no method for involuntary punishment beyond those that exist in its absence; and yet, in its role reducing costs in the aggregation of information, the Law proves indispensable. What a beautiful example of how theory can clarify our observations!

“The Role of Institutions in the Revival of Trade” appeared in Economics and Politics 1.2, March 1990, and extensions of these ideas to long distance trade with many centers are considered in the papers by Avner Greif and his coauthors linked at the beginning of this post. A broad philosophical defense of the importance of transaction costs to economic history is North’s 1984 essay in the Journal of Institutional and Theoretical Economics. Two other titans of economics have also recently passed away, I’m afraid. Herbert Scarf, the mathematician whose work is of fundamental importance to modern market design, was eulogized by Ricky Vohra and Al Roth. Nate Rosenberg, who with Zvi Griliches was the most important thinker on the economics of invention, was memorialized by Joshua Gans and Joel West.

“Inventing Prizes: A Historical Perspective on Innovation Awards and Technology Policy,” B. Z. Khan (2015)

B. Zorina Khan is an excellent and underrated historian of innovation policy. In her new working paper, she questions the shift toward prizes as an innovation inducement mechanism. The basic problem economists have been grappling with is that patents are costly in terms of litigation, largely due to their uncertainty, that patents impose deadweight loss by granting inventors market power (as noted at least as far back as Nordhaus 1969), and that patent rights can lead to an anticommons which in some cases harms follow-on innovation (see Scotchmer and Green and Bessen and Maskin for the theory, and papers like Heidi Williams’ genome paper for empirics).

There are three main alternatives to patents, as I see them. First, you can give prizes, determined ex-ante or ex-post. Second, you can fund R&D directly with government, as the NIH does for huge portions of medical research. Third, you can rely on inventors accruing rents to cover the R&D without any government action, such as by keeping their invention secret, relying on first mover advantage, or having market power in complementary goods. We have quite a bit of evidence that the second, in biotech, and the third, in almost every other field, is the primary driver of innovative activity.

Prizes, however, are becoming more and more common. There are X-Prizes for space and AI breakthroughs, advanced market commitments for new drugs with major third world benefits, Kremer’s “patent buyout” plan, and many others. Setting the prize amount right is of course a challenging project (one that Kremer’s idea partially fixes), and in this sense prizes run “less automatically” than the patent system. What Khan notes is that prizes have been used frequently in the history of innovation, and were frankly common in the late 18th and 19th century. How useful were they?

Unfortunately, prizes seem to have suffered many problems. Khan has an entire book on The Democratization of Invention in the 19th century. Foreign observers, and not just Tocqueville, frequently noted how many American inventors came from humble backgrounds, and how many “ordinary people” were dreaming up new products and improvements. This frenzy was often, at the time, credited to the uniquely low-cost and comprehensive U.S. patent system. Patents were simple enough, and inexpensive enough, to submit that credit for and rights to inventions pretty regularly flowed to people who were not politically well connected, and for inventions that were not “popular”.

Prizes, as opposed to patents, often incentivized the wrong projects and rewarded the wrong people. First, prizes were too small to be economically meaningful; when the well-named Hippolyte Mège-Mouriès made his developments in margarine and garnered the prize offered by Napoleon III, the value of that prize was far less than the value of the product itself. In order to shift effort with prizes, the prize designer needs to know both enough about the social value of the proposed invention to set the prize amount high enough, and enough about the value of alternatives that the prize doesn’t distort effort away from other inventions that would be created while relying solely on trade secrecy and first mover advantage (I discuss this point in much greater depth in my Direction of Innovation paper with Jorge Lemus). Providing prizes to only some inventions may either generate no change in behavior at all because the prize is too small compared with the other benefits of inventing, or cause inefficient distortions in behavior. Even though, say, a malaria vaccine would be very useful, an enormous prize for a malaria vaccine will distort health researcher effort away from other projects in a way that is tough to calculate ex-ante without a huge amount of prize designer knowledge.

There is a more serious problem with prizes. Because the cutoff for a prize is less clear cut, there is more room for discretion and hence a role for wasteful lobbying and personal connection to trump “democratic invention”. Khan notes that even though the French buyout of Daguerre’s camera patent is cited as a classic example of a patent buyout in the famous Kremer QJE article, it turns out that Daguerre never actually held any French patent at all! What actually happened was that Daguerre lobbied the government for a sinecure in order to make his invention public, but then patented it abroad anyway! There are many other political examples, such as the failure of the uneducated clockmaker John Harrison to be granted a prize for his work on longitude due partially to the machinations of more upper class competitors who captured the ear of the prize committee. Examining a database of great inventors on both sides of the Atlantic, Khan found that prizes were often linked to factors like overcoming hardship, having an elite education, or regional ties. That is, the subjectivity of prizes may be stronger than the subjectivity of patents.

So then, we have three problems: prize designers don’t know enough about the relative import of various ideas to set price amounts optimally, prizes in practice are often too small to have much effect, and prizes lead to more lobbying and biased rewards than patents. We shouldn’t go too far here; prizes still may be an important part of the innovation policy toolkit. But the history Khan lays out certainly makes me more sanguine that they are a panacea.

One final point. I am unconvinced that patents really help the individual or small inventor very much either. I did a bit of hunting: as far as I can tell, there is not a single billionaire who got that way primarily by selling their invention. Many people developed their invention in a firm, but non-entrepreneurial invention, for which the fact that patents create a market for knowledge is supposedly paramount, doesn’t seem to be making anyone super rich. This is even though there are surely a huge number of inventions each worth billions. A good defense of patents as our main innovation policy should really grapple better with this fact.

July 2015 NBER Working Paper (RePEc IDEAS). I’m afraid the paper is gated if you don’t have an NBER subscription, and I was unable to find an ungated copy.

On the economics of the Neolithic Revolution

The Industrial and Neolithic Revolutions are surely the two fundamental transitions in the economic history of mankind. The Neolithic involved permanent settlement of previously nomadic, or at best partially foraging, small bands. At least seven independent times, bands somewhere in the world adopted settled agriculture. The new settlements tended to see an increase in inequality, the beginning of privately held property, a number of new customs and social structures, and, most importantly, an absolute decrease in welfare as measured in terms of average height and an absolute increase in the length and toil of working life. Of course, in the long run, settlement led to cities which led to the great inventions that eventually pushed mankind past the Malthusian bounds into our wealthy present, but surely no nomad of ten thousand years ago could have projected that outcome.

Now this must sound strange to any economist, as we can’t help but think in terms of rational choice. Why would any band choose to settle when, as far as we can tell, settling made them worse off? There are only three types of answers compatible with rational choice: either the environment changed such that the nomads who adopted settlement would have been even worse off had they remained nomadic, settlement was a Pareto-dominated equilibrium, or our assumption that the nomads were maximizing something correlated with height is wrong. All might be possible: early 20th century scholars ascribed the initial move to settlement to humans being forced onto oases in the drying post-Ice Age Middle East, evolutionary game theorists are well aware that fitness competitions can generate inefficient Prisoner’s Dilemmas, and humans surely care about reproductive success more than they care about food intake per se.

So how can we separate these potential explanations, or provide greater clarity as to the underlying Neolithic transition mechanism? Two relatively new papers, Andrea Matranga’s “Climate-Driven Technical Change“, and Kim Sterelny’s Optimizing Engines: Rational Choice in the Neolithic”, discuss intriguing theories about what may have happened in the Neolithic.

Matranga writes a simple Malthusian model. The benefit of being nomadic is that you can move to places with better food supply. The benefit of being sedentary is that you use storage technology to insure yourself against lean times, even if that insurance comes at the cost of lower food intake overall. Nomadism, then, is better than settling when there are lots of nearby areas with uncorrelated food availability shocks (since otherwise why bother to move?) or when the potential shocks you might face across the whole area you travel are not that severe (in which case why bother to store food?). If fertility depends on constant access to food, then for Malthusian reasons the settled populations who store food will grow until everyone is just at subsistence, whereas the nomadic populations will eat a surplus during times when food is abundant.

It turns out that global “seasonality” – or the difference across the year in terms of temperature and rainfall – was extraordinarily high right around the time agriculture first popped up in the Fertile Crescent. Matranga uses some standard climatic datasets to show that six of the seven independent inventions of agriculture appear to have happened soon after increases in seasonality in their respective regions. This is driven by an increase in seasonality and not just an increase in rainfall or heat: agriculture appears in the cold Andes and in the hot Mideast and in the moderate Chinese heartland. Further, adoption of settlement once your neighbors are farming is most common when you live on relatively flat ground, with little opportunity to change elevation to pursue food sources as seasonality increases. Biological evidence (using something called “Harris lines” on your bones) appears to support to idea that nomads were both better fed yet more subject to seasonal shocks than settled peoples.

What’s nice is that Matranga’s hypothesis is consistent with agriculture appearing many times independently. Any thesis that relies on unique features of the immediate post-Ice Age – such as the decline in megafauna like the Woolly Mammoth due to increasing population, or the oasis theory – will have a tough time explaining the adoption of agriculture in regions like the Andes or China thousands of years after it appeared in the Fertile Crescent. Alain Testart and colleagues in the anthropology literature have made similar claims about the intersection of storage technology and seasonality being important for the gradual shift from nomadism to partial foraging to agriculture, but the Malthusian model and the empirical identification in Matranga will be much more comfortable for an economist reader.

Sterelny, writing in the journal Philosophy of Science, argues that rational choice is a useful framework to explain not only why backbreaking, calorie-reducing agriculture was adopted, but also why settled societies appeared willing to tolerate inequality which was much less common in nomadic bands, and why settled societies exerted so much effort building monuments like Gobekli Tepe, holding feasts, and participating in other seemingly wasteful activity.

Why might inequality have arisen? Settlements need to be defended from thieves, as they contain stored food. Hence settlement sizes may be larger than the size of nomadic bands. Standard repeated games with imperfect monitoring tell us that when repeated interactions become less common, cooperation norms become hard to sustain. Hence collective action can only be sustained through mechanisms other than dyadic future punishment; this is especially true if farmers have more private information about effort and productivity than a band of nomadic hunters. The rise of enforceable property rights, as Bowles and his coauthors have argued, is just such a mechanism.

What of wasteful monuments like Gobekli Tepe? Game theoretic deliberate choice provides two explanations for such seeming wastefulness. First, just as animals consume energy in ostentatious displays in order to signal their fitness (as the starving animal has no energy to generate such a display), societies may construct totems and temples in order to signal to potential thieves that they are strong and not worth trifling with. In the case of Gobekli Tepe, this doesn’t appear to be the case, as there isn’t much archaeological evidence of particular violence around the monument. A second game theoretic rationale, then, is commitment by members of a society. As Sterelny puts it, the reason a gang makes a member get a face tattoo is that, even if the member leaves the gang, the tattoo still puts that member at risk of being killed by the gang’s enemies. Hence the tattoo commits the member not to defect. Settlements around Gobekli Tepe may have contributed to its building in order to commit their members to a set of norms that the monument embodied, and hence permit trade and knowledge transfer within this in-group. I would much prefer to see a model of this hypothesis, but the general point doesn’t seem impossible. At least, Sterelny and Matranga together provide a reasonably complete possible explanation, based on rational behavior and nothing more, of the seemingly-strange transition away from nomadism that made our modern life possible.

Kim Sterelny, Optimizing Engines: Rational Choice in the Neolithic?, 2013 working paper. Final version published in the July 2015 issue of Philosophy of Science. Andrea Matranga, “Climate-driven Technical Change: Seasonality and the Invention of Agriculture”, February 2015 working paper, as yet unpublished. No RePEc IDEAS page is available for either paper.

“Editor’s Introduction to The New Economic History and the Industrial Revolution,” J. Mokyr (1998)

I taught a fun three hours on the Industrial Revolution in my innovation PhD course this week. The absolutely incredible change in the condition of mankind that began in a tiny corner of Europe in an otherwise unremarkable 70-or-so years is totally fascinating. Indeed, the Industrial Revolution and its aftermath are so important to human history that I find it strange that we give people PhDs in social science without requiring at least some study of what happened.

My post today draws heavily on Joel Mokyr’s lovely, if lengthy, summary of what we know about the period. You really should read the whole thing, but if you know nothing about the IR, there are really five facts of great importance which you should be aware of.

1) The world was absurdly poor from the dawn of mankind until the late 1800s, everywhere.
Somewhere like Chad or Nepal today fares better on essentially any indicator of development than England, the wealthiest place in the world, in the early 1800s. This is hard to believe, I know. Life expectancy was in the 30s in England, infant mortality was about 150 per 1000 live births, literacy was minimal, and median wages were perhaps 3 to 4 times subsistence. Chad today has a life expectancy of 50, infant mortality of 90 per 1000, a literacy of 35%, and urban median wages of roughly 3 to 4 times subsistence. Nepal fares even better on all counts. The air from the “dark, Satanic mills” of William Blake would have made Beijing blush, “night soil” was generally just thrown on to the street, children as young as six regularly worked in mines, and 60 to 80 hours a week was a standard industrial schedule.

The richest places in the world were never more than 5x subsistence before the mid 1800s

Despite all of this, there was incredible voluntary urbanization: those dark, Satanic mills were preferable to the countryside. My own ancestors were among the Irish that fled the Potato famine. Mokyr’s earlier work on the famine, which happened in the British Isles after the Industrial Revolution, suggest 1.1 to 1.5 million people died from a population of about 7 million. This is similar to the lower end of the range for percentage killed during the Cambodian genocide, and similar to the median estimates of the death percentage during the Rwandan genocide. That is, even in the British Isles, famines that would shock the world today were not unheard of. And even if you wanted to leave the countryside, it may have been difficult to do so. After Napoleon, serfdom remained widespread east of the Elbe river in Europe, passes like the “Wanderbucher” were required if one wanted to travel, and coercive labor institutions that tied workers to specific employers were common. This is all to say that the material state of mankind before and during the Industrial Revolution, essentially anywhere in the world, would be seen as outrageous deprivation to us today; palaces like Versailles are not representative, as should be obvious, of how most people lived. Remember also that we are talking about Europe in the early 1800s; estimates of wages in other “rich” societies of the past are even closer to subsistence.

2) The average person did not become richer, nor was overall economic growth particularly spectacular, during the Industrial Revolution; indeed, wages may have fallen between 1760 and 1830.

The standard dating of the Industrial Revolution is 1760 to 1830. You might think: factories! The railroad! The steam engine! High Britannia! How on Earth could people have become poorer? And yet it is true. Brad DeLong has an old post showing Bob Allen’s wage reconstructions: Allen found British wages lower than their 1720 level in 1860! John Stuart Mill, in his 1870 textbook, still is unsure whether all of the great technological achievements of the Industrial Revolution would ever meaningfully improve the state of the mass of mankind. And Mill wasn’t the only one who noticed, there were a couple of German friends, who you may know, writing about the wretched state of the Working Class in Britain in the 1840s as well.

3) Major macro inventions, and growth, of the type seen in England in the late 1700s and early 1800s happened many times in human history.

The Iron Bridge in Shropshire, 1781, proving strength of British iron

The Industrial Revolution must surely be “industrial”, right? The dating of the IR’s beginning to 1760 is at least partially due to the three great inventions of that decade: the Watt engine, Arkwright’s water frame, and the spinning jenny. Two decades later came Cort’s famous puddling process for making strong iron. The industries affected by those inventions, cotton and iron, are the prototypical industries of England’s industrial height.

But if big macro-inventions, and a period of urbanization, are “all” that defines the Industrial Revolution, then there is nothing unique about the British experience. The Song Dynasty in China saw the gun, movable type, a primitive Bessemer process, a modern canal lock system, the steel curved moldboard plow, and a huge increase in arable land following public works projects. Netherlands in the late 16th and early 17th century grew faster, and eventually became richer, than Britain ever did during the Industrial Revolution. We have many other examples of short-lived periods of growth and urbanization: ancient Rome, Muslim Spain, the peak of the Caliphate following Harun ar-Rashid, etc.

We care about England’s growth and invention because of what followed 1830, not what happened between 1760 and 1830. England was able to take their inventions and set on a path to break the Malthusian bounds – I find Galor and Weil’s model the best for understanding what is necessary to move from a Malthusian world of limited long-run growth to a modern world of ever-increasing human capital and economic bounty. Mokyr puts it this way: “Examining British economic history in the period 1760-1830 is a bit like studying the history of Jewish dissenters between 50 B.C. and 50 A.D. At first provincial, localized, even bizarre, it was destined to change the life of every man and women…beyond recognition.”

4) It is hard for us today to understand how revolutionary ideas like “experimentation” or “probability” were.

In his two most famous books, The Gifts of Athena and The Lever of Riches, Mokyr has provided exhausting evidence about the importance of “tinkerers” in Britain. That is, there were probably something on the order of tens of thousands of folks in industry, many not terribly well educated, who avidly followed new scientific breakthroughs, who were aware of the scientific method, who believed in the existence of regularities which could be taken advantage of by man, and who used systematic processes of experimentation to learn what works and what doesn’t (the development of English porter is a great case study). It is impossible to overstate how unusual this was. In Germany and France, science was devoted mainly to the state, or to thought for thought’s sake, rather than to industry. The idea of everyday, uneducated people using scientific methods somewhere like ar-Rashid’s Baghdad is inconceivable. Indeed, as Ian Hacking has shown, it wasn’t just that fundamental concepts like “probabilistic regularities” were difficult to understand: the whole concept of discovering something based on probabilistic output would not have made sense to all but the very most clever person before the Enlightenment.

The existence of tinkerers with access to a scientific mentality was critical because it allowed big inventions or ideas to be refined until they proved useful. England did not just invent the Newcomen engine, put it to work in mines, and then give up. Rather, England developed that Newcomen engine, a boisterous monstrosity, until it could profitably be used to drive trains and ships. In Gifts of Athena, Mokyr writes that fortune may sometimes favor the unprepared mind with a great idea; however, it is the development of that idea which really matters, and to develop macroinventions you need a small but not tiny cohort of clever, mechanically gifted, curious citizens. Some have given credit to a political system, or to the patent system, for the widespread tinkering, but the qualitative historical evidence I am aware of appears to lean toward cultural explanations most strongly. One great piece of evidence is that contemporaries wrote often about the pattern where Frenchmen invented something of scientific importance, yet the idea diffused and was refined in Britain. Any explanation of British uniqueness must depend on Britain’s ability to refine inventions.

5) The best explanations for “why England? why in the late 1700s? why did growth continue?” do not involve colonialism, slavery, or famous inventions.

First, we should dispose of colonialism and slavery. Exports to India were not particularly important compared to exports to non-colonial regions, slavery was a tiny portion of British GDP and savings, and many other countries were equally well-disposed to profit from slavery and colonialism as of the mid-1700s, yet the IR was limited to England. Expanding beyond Europe, Dierdre McCloskey notes that “thrifty self-discipline and violent expropriation have been too common in human history to explain a revolution utterly unprecedented in scale and unique to Europe around 1800.” As for famous inventions, we have already noted how common bursts of cleverness were in the historic record, and there is nothing to suggest that England was particularly unique in its macroinventions.

To my mind, this leaves two big, competing explanations: Mokyr’s argument that tinkerers and a scientific mentality allowed Britain to adapt and diffuse its big inventions rapidly enough to push the country over the Malthusian hump and into a period of declining population growth after 1870, and Bob Allen’s argument that British wages were historically unique. Essentially, Allen argues that British wages were high compared to its capital costs from the Black Death forward. This means that labor-saving inventions were worthwhile to adopt in Britain even when they weren’t worthwhile in other countries (e.g., his computations on the spinning jenny). If it worthwhile to adopt certain inventions, then inventors will be able to sell something, hence it is worthwhile to invent certain inventions. Once adopted, Britain refined these inventions as they crawled down the learning curve, and eventually it became worthwhile for other countries to adopt the tools of the Industrial Revolution. There is a great deal of debate about who has the upper hand, or indeed whether the two views are even in conflict. I do, however, buy the argument, made by Mokyr and others, that it is not at all obvious that inventors in the 1700s were targeting their inventions toward labor saving tasks (although at the margin we know there was some directed technical change in the 1860s), nor it is even clear that invention overall during the IR was labor saving (total working hours increased, for instance).

Mokyr’s Editor’s Introduction to “The New Economic History and the Industrial Revolution” (no RePEc IDEAS page). He has a followup in the Journal of Economic History, 2005, examining further the role of an Enlightenment mentality in allowing for the rapid refinement and adoption of inventions in 18th century Britain, and hence the eventual exit from the Malthusian trap.

“Entrepreneurship: Productive, Unproductive and Destructive,” W. Baumol (1990)

William Baumol, who strikes me as one of the leading contenders for a Nobel in the near future, has written a surprising amount of interesting economic history. Many economic historians see innovation – the expansion of ideas and the diffusion of products containing those ideas, generally driven by entrepreneurs – as critical for growth. But we find it very difficult to see any reason why the “spirit of innovation” or the net amount of cleverness in society is varying over time. Indeed, great inventions, as undeveloped ideas, occur almost everywhere at almost all times. The steam engine of Heron of Alexandria, which was used for parlor tricks like opening temple doors and little else, is surely the most famous example of a great idea, undeveloped.

Why, then, do entrepreneurs develop ideas and cause products to diffuse widely at some times in history and not at others? Schumpeter gave five roles for an entrepreneur: introducing new products, new production methods, new markets, new supply sources or new firm and industry organizations. All of these are productive forms of entrepreneurship. Baumol points out that clever folks can also spend their time innovating new war implements, or new methods of rent seeking, or new methods of advancing in government. If incentives are such that those activities are where the very clever are able to prosper, both financially and socially, then it should be no surprise that “entrepreneurship” in this broad sense is unproductive or, worse, destructive.

History offers a great deal of support here. Despite quite a bit of productive entrepreneurship in the Middle East before the rise of Athens and Rome, the Greeks and Romans, especially the latter, are well-known for their lack of widespread diffusion of new productive innovations. Beyond the steam engine, the Romans also knew of the water wheel yet used it very little. There are countless other examples. Why? Let’s turn to Cicero: “Of all the sources of wealth, farming is the best, the most able, the most profitable, the most noble.” Earning a governorship and stripping assets was also seen as noble. What we now call productive work? Not so much. Even the freed slaves who worked as merchants had the goal of, after acquiring enough money, retiring to “domum pulchram, multum serit, multum fenerat”: a fine house, land under cultivation and short-term loans for voyages.

Baumol goes on to discuss China, where passing the imperial exam and moving into government was the easiest way to wealth, and the early middle ages of Europe, where seizing assets from neighboring towns was more profitable than expanding trade. The historical content of Baumol’s essay was greatly expanded in a book he edited alongside Joel Mokyr and David Landes called The Invention of Enterprise, which discusses the relative return to productive entrepreneurship versus other forms of entrepreneurship from Babylon up to post-war Japan.

The relative incentives for different types of “clever work” are relevant today as well. Consider Luigi Zingales’ new lecture, Does Finance Benefit Society? I can’t imagine anyone would consider Zingales hostile to the financial sector, but he nonetheless discusses in exhaustive detail the ways in which incentives push some workers in that sector toward rent-seeking and fraud rather than innovation which helps the consumer.

Final JPE copy (RePEc IDEAS). Murphy, Schleifer and Vishny have a paper, also from the JPE in 1990, on the topic of how clever people in many countries are incentivized toward rent-seeking; their work is more theoretical and empirical than historical. If you are interested in innovation and entrepreneurship, I uploaded the reading list for my PhD course on the topic here.

“Forced Coexistence and Economic Development: Evidence from Native American Reservations,” C. Dippel (2014)

I promised one more paper from Christian Dippel, and it is another quite interesting one. There is lots of evidence, folk and otherwise, that combining different ethnic or linguistic groups artificially, as in much of the ex-colonial world, leads to bad economic and governance outcomes. But that’s weird, right? After all, ethnic boundaries are themselves artificial, and there are tons of examples – Italy and France being the most famous – of linguistic diversity quickly fading away once a state is developed. Economic theory (e.g., a couple recent papers by Joyee Deb) suggests an alternative explanation: groups that have traditionally not worked with each other need time to coordinate on all of the Pareto-improving norms you want in a society. That is, it’s not some kind of intractable ethnic hate, but merely a lack of trust that is the problem.

Dippel uses the history of American Indian reservations to examine the issue. It turns out that reservations occasionally included different subtribal bands even though they almost always were made up of members of a single tribe with a shared language and ethnic identity. For example, “the notion of tribe in Apachean cultures is very weakly developed. Essentially it was only a recognition
that one owed a modicum of hospitality to those of the same speech, dress, and customs.” Ethnographers have conveniently constructed measures of how integrated governance was in each tribe prior to the era of reservations; some tribes had very centralized governance, whereas others were like the Apache. In a straight OLS regression with the natural covariates, incomes are substantially lower on reservations made up of multiple bands that had no pre-reservation history of centralized governance.

Why? First, let’s deal with identification (more on what that means in a second). You might naturally think that, hey, tribes with centralized governance in the 1800s were probably quite socioeconomically advanced already: think Cherokee. So are we just picking up that high SES in the 1800s leads to high incomes today? Well, in regions with lots of mining potential, bands tended to be grouped onto one reservation more frequently, which suggests that resource prevalence on ancestral homelands outside of the modern reservation boundaries can instrument for the propensity for bands to be placed together. Instrumented estimates of the effect of “forced coexistence” is just as strong as the OLS estimate. Further, including tribe fixed effects for cases where single tribes have a number of reservations, a surprisingly common outcome, also generates similar estimates of the effect of forced coexistence.

I am very impressed with how clear Dippel is about what exactly is being identified with each of these techniques. A lot of modern applied econometrics is about “identification”, and generally only identifies a local average treatment effect, or LATE. But we need to be clear about LATE – much more important than “what is your identification strategy” is an answer to “what are you identifying anyway?” Since LATE identifies causal effects that are local conditional on covariates, and the proper interpretation of that term tends to be really non-obvious to the reader, it should go without saying that authors using IVs and similar techniques ought be very precise in what exactly they are claiming to identify. Lots of quasi-random variation generates that variation along a local margin that is of little economic importance!

Even better than the estimates is an investigation of the mechanism. If you look by decade, you only really see the effect of forced coexistence begin in the 1990s. But why? After all, the “forced coexistence” is longstanding, right? Think of Nunn’s famous long-run effect of slavery paper, though: the negative effects of slavery are mediated during the colonial era, but are very important once local government has real power and historically-based factionalism has some way to bind on outcomes. It turns out that until the 1980s, Indian reservations had very little local power and were largely run as government offices. Legal changes mean that local power over the economy, including the courts in commercial disputes, is now quite strong, and anecdotal evidence suggests lots of factionalism which is often based on longstanding intertribal divisions. Dippel also shows that newspaper mentions of conflict and corruption at the reservation level are correlated with forced coexistence.

How should we interpret these results? Since moving to Canada, I’ve quickly learned that Canadians generally do not subscribe to the melting pot theory; largely because of the “forced coexistence” of francophone and anglophone populations – including two completely separate legal traditions! – more recent immigrants are given great latitude to maintain their pre-immigration culture. This heterogeneous culture means that there are a lot of actively implemented norms and policies to help reduce cultural division on issues that matter to the success of the country. You might think of the problems on reservations and in Nunn’s post-slavery states as a problem of too little effort to deal with factionalism rather than the existence of the factionalism itself.

Final working paper, forthcoming in Econometrica. No RePEc IDEAS version. Related to post-colonial divisions, I also very much enjoyed Mobilizing the Masses for Genocide by Thorsten Rogall, a job market candidate from IIES. When civilians slaughter other civilians, is it merely a “reflection of ancient ethnic hatred” or is it actively guided by authority? In Rwanda, Rogall finds that almost all of the killing is caused directly or indirectly by the 50,000-strong centralized armed groups who fanned out across villages. In villages that were easier to reach (because the roads were not terribly washed out that year), more armed militiamen were able to arrive, and the more of them that arrived, the more deaths resulted. This in-person provoking appears much more important than the radio propaganda which Yanigazawa-Drott discusses in his recent QJE; one implication is that post-WW2 restrictions on free speech in Europe related to Nazism may be completely misdiagnosing the problem. Three things I especially liked about Rogall’s paper: the choice of identification strategy is guided by a precise policy question which can be answered along the local margin identified (could a foreign force stopping these centralized actors a la Romeo Dallaire have prevented the genocide?), a theoretical model allows much more in-depth interpretation of certain coefficients (for instance, he can show that most villages do not appear to have been made up of active resistors), and he discusses external cases like the Lithuanian killings of Jews during World War II, where a similar mechanism appears to be at play. I’ll have many more posts on cool job market papers coming shortly!