Paul Romer: The view from economic history

by Nuno Palma (University of Manchester and CEPR). Republished with minor adjustments from the blog “Economic Growth in History”


In this post I write about the connections between Paul Romer’s work, which is essentially applied theory, and the empirical work on long-run economic growth done by economic historians. How was Romer influenced by the work of economic historians? has he influenced economic history? and have his theories been confirmed by the recent work of economic historians? (preview: I will argue that the answers are: yes; not much; and no). Nevertheless, my point above is not that Romer is wrong in general; in fact some of his ideas *about ideas* are fundamental for us to think about growth in the past (read on if this isn’t clear yet.)


Paul Romer in 2005. Wikimedia Commons

Paul Romer’s was a well-deserved and long-anticipated prize. Many predicted he would eventually win, including myself in my very first academic article, written when I was a undergradute and published in 2008. (ungated version here). I now find it mildly amusing how assertive I was when I wrote: “Paul Romer is going to win the Nobel Prize in economics”. I continue to believe that this was a good choice.

Many have written about the nature of his main contributions, all of which, as I have said, have been on applied theory; see for instance, see the posts in Dietrich Vollrath’s blog, here and here, or in Paul Romer’s own blog.

Romer’s work had some influence on economic history, but not much. There is, for instance, a 1995 article by Nick Crafts which looks at the Industrial Revolution from a New Growth perspective, but it is fair to say that economic historians were perhaps not quick to pick up the New Growth theory train. Part of this was surely because its implications seemed to apply mostly to frontier economies and did not seem to apply to much of human history, a limitation which Unified Growth Theory would later attempt to overcome.

And yet, Romer himself has often spoken about economic history and relied on the data of economic historians. He now seems to have won mostly due to his 1990 article, but his earlier work on increasing returns (ungated version here) had a graph from Maddison, for instance.

One of the most empirical papers Romer has written is “Why indeed in America?”,  which was the culmination of much of what he had done before. It was also one of the last papers he wrote before entering a writing hiatus. In this paper he explicitly argues for the complementarity of economic history and growth theory. He argues that the USA achieved economic supremacy after 1870 due to having the largest integrated market in the world. He writes:

“differences in saving and education do not explain why growth was so much faster in the United States than it was in Britain around the turn of this century. In 1870, per capita income in the United States was 75 percent of per capita income in Britain. By 1929, it had increased to 130 percent. In the intervening decades, years of education per worker increased by a factor of 2.2 in Britain and by a nearly identical factor of 2.3 in the United States. In 1929, this variable remained slightly lower in the United States. (Data are taken from Angus Maddison [1995].”

Notice that there are three empirical statements here. Romer’s story builds on these facts, so if the facts change, the story must too. Theory depends on facts.

The first fact (according to Romer) is that the US only converged to British per capita GDP levels after 1870. Second, that this was not due to matters such as education or savings. Third, the reason was market size. As economic historians, we have made much progress in measuring each of these matters since 1995. Let me consider each in turn.

Timing of convergence of the USA to Britain

The important thing to keep in mind here is that it is by no means certain that the USA had not catched up earlier. The methodological issues are complicated and in fact today’s other (and equally deserving) Nobel prize, Nordhaus, wrote a fascinating paper about the problems involved in these types of measurements. (A popular description of this work can be read here) As far as USA vs Britain is concerned, though, Marianne Ward and John Devereux summarize the debate as follows:

“Prados De la Escosura (2000) and Ward and Devereux (2003, 2004, 2005) argue for an early US income lead using current price estimates. Broadberry (2003) and Broadberry and Irwin (2006) defend the Maddison projections while Woltjer (2015) hews to a middle ground. The literature has recently taken an unexpected turn as Peter Lindert and Jeffrey Williamson, Lindert and Williamson (2016), find a larger US lead before 1870 and one that stretches further back in time than claimed by either Prados De la Escosura (2000) or Ward and Devereux (2005).”

Comparative levels of education

Recent evidence suggests that the average years of post-primary education actually declined in Britain after about 1700 (ungated version here). This was not the case at all in the USA, where it is well-known that the state invested in high schools, so it seems unlikely that average human capital grew at similar levels in the latter part of the 19th century, as Maddison/Romer claimed.

Market size

I used to believe this part of Romer’s story. That was until I read this brilliant paper by Leslie Hannah: “Logistics, Market Size, and Giant Plants in the Early Twentieth Century: A Global View” (ungated version here). Notice that Hannah does not refer to Romer’s argument or even cite him. What he does instead is he destroys the commonly held idea that USA’s market size was larger that Europe’s already before the Great War (aka World War I). It is true that the USA had more railroads, but it also had much longer distances. In Northwestern Europe, transportation by a mix of ships, trains and horses was cheaper, especially once we consider the much denser (and highly urbanized) population. It is important to remember that prior to WWI, Europe was living the “first age of globalization”, with high levels of integration and relatively low tariffs.

So, this part of Romer’s story cannot be right.


In conclusion, what does this all mean? will these new facts affect where growth theory will go? only time will tell, and growth theory itself is by no means moving much these days, as Paul Romer himself has addmited in recent interviews. What these facts suggest, though, is that other things must have mattered.

As I said in the beginning, I believe that Paul Romer’s applied theory work is important (as it is that of others that might have won, such as Aghion and Howitt). The natural complementaries between the work of economic historians and applied theorists suggest that we need to listen to each other in order for science to move forward. Hopefully, new generations of economists will do a bit of both, as have some people who now work on Unified Growth.

But in the future, it is fair that the Nobel committee gives more prizes to empirical work as well. Because theory can’t live without facts, but economics Nobels have been highly biased towards theorists (whether pure or applied).


To contact the author: @nunopgpalma


Review: Avner Offer and Gabriel Soderberg, The Nobel Factor: The Prize in Economics, Social Democracy and the Market Turn (Princeton University Press, 2016)

The Nobel Factor: On the eve of the announcement of the Nobel prize in economics we review Offer and Soderberg’s new book and ask “What relationship should economic historians have to economics? ” 


What relationship should economic historians have to economics? For those who see economic history as essentially applied economics, the answer is perhaps obvious. But for those of us who see ourselves as ‘historians who are interested in the economy’, the question is fundamental – and difficult to answer. EHS co-founder R. H. Tawney, rejecting the Marshallian economics of his day, asserted that ‘There is no such thing as a science of economics, nor ever will be. It is just cant…’

Tempting as such a wholehearted rejection might sometimes be, it plainly won’t do. Whatever one’s ultimate judgment about its knowledge claims, economics is the most powerful, influential social science. For good or ill, economic historians are fated to spend our lives grappling with the discipline.

In an ideal world, economic historians would be equipped with a profound knowledge of economics, coupled with a profound scepticism about its capacity to help us understand how things work. This book demonstrates that its authors possess both these virtues. They use the Nobel prize in economics, awarded since 1969, as a means of examining the nature and role of economics in a book whose depth and breadth of vision make it a hugely important contribution to our understanding of the ‘market turn’ in economic policy over the last 40 years.

The Nobel prize in economics arose from an initiative of the Swedish central bank to raise the prestige of both itself and the discipline of economics, in the context of the bank’s struggle with Sweden’s governing Social Democrats. Like most central banks, the Riksbank prioritised low inflation and limited government; and it was hostile to the stabilising and equalising policies pursued by Sweden’s dominant political party.

Offer and Soderberg offer a sustained analysis of the pattern of winners of the prize. Over its whole history, there has been a careful attempt to award the prize to a balance of economists, with the most famous case being the 1974 joint prize awarded to Friedrich Hayek and the Swedish social democratic theorist, Gunnar Myrdal.

This balancing act has helped to maintain the high prestige of the prize, while also acting to undermine the ‘scientific’ pretensions of the discipline. Not only have the prize-winners come from a wide range of positions in economics, but several have also been acknowledged for contributions that directly or indirectly contradict the work of other recipients.

Much of the most detailed analysis of economics here concentrates on undermining the claims of the ‘market liberals’, a term embracing proponents of the new classical macroeconomics, rational expectations and public choice. The book is scathing about the claims made for these (and other) theories, arguing that they ultimately rest on ethical presuppositions, while showing little capacity to explain empirical changes in the economy.

The failure of the awarders of the Nobel prize to be concerned with empirical validity is seen as their biggest failing in how they have made their judgments. As the authors suggest, while Hayek opposed the scientistic pretensions of many economists, his own work, most notably his Road to Serfdom, has been ‘grotesquely falsified’ (p.9). The expansion of the state in post-war Western Europe, far from leading to a slippery slope of ‘serfdom’ has been combined with an enlargement of freedom, however that capacious term is defined. (While Hayek, Milton Friedman and other Nobel prize-winners were keen supporters of the Chilean dictator and murderer Pinochet in the name of ‘economic freedom’).

Despite their aversion to the ‘theoretical mumbo jumbo’ (p.212) of some economics and their dismissal of the scientific claims of many of the practitioners of the discipline, the authors by no means share Tawney’s dismissive attitude. Economics they proclaim, in one of the books many bon mots, ‘is not easy to master, but it is easy to believe.’ (p.2).

Their response is to undermine such ready belief, by showing that the effort at mastery is not wasted, as it allows us to exercise informed discrimination. Some economics is extremely useful. They are particularly enthusiastic about national accounting: ‘The best empirical programme in twentieth-century economics… an empirical, pragmatic and practical model of general equilibrium, based on a deep understanding and knowledge of the economy.’ (p.153)

This book is hugely persuasive about economics, where the knowledge displayed is extraordinary and the judgments highly persuasive. On social democracy, it is perhaps not so strong. There is some fascinating discussion of the development of Swedish social democracy and its relationship to key Swedish economists.

Most attention is given to Assar Lindbeck, a long-term member of the Nobel prize committee and its chair from 1980 to 1994. His work and role is subject to a blistering attack, coupled with a persuasive defence of the benefits of his country’s version of social democracy, which he renounced and then bitterly attacked.

But social democracy comes in many different forms, whereas in this book, the ‘Swedish model’ is used to define a singular form, characterised, we are told, by a collective provision response to insecurity over the lifecycle. Thus, ‘The difference between Social Democracy and economic market doctrine is easy to draw. It is about how to deal with uncertainty.’ (p.5)

While this stark, one-dimensional, definition is somewhat qualified elsewhere, the persistent assertion of its foundational status raises two problems. First, there is a question about how far such positioning is exclusive to social democracy. Most obviously, perhaps, would not Beveridge-style social insurance fit this definition? The Liberal William Beveridge proclaimed ‘social insurance for all and for every contingency’; with all its mid-twentieth century trappings, surely a clear advocacy of a collective response to security over the lifestyle?

Conversely, social democrats outside Sweden have focused less on redistribution of income over the lifecycle and more, for example, on more direct ‘vertical’ redistribution or on collective control of the means of production or on economic planning. They may have been strategically mistaken, but that is surely no reason to deny them the ‘social democrat’ label?

Jim Tomlinson

University of Glasgow