A quarterly magazine of the IMF

June 2006, Volume 43, Number 2

People in Economics

Economist as Crusader

Arvind Subramanian interviews economist Paul Krugman

Economics made Paul Krugman famous. Punditry has made him a celebrity, famous for being famous. But Krugman aspires to be long remembered, and, in this respect, John Maynard Keynes is the gold standard. Keynes left his mark in three distinct ways: through the power of ideas, through the art of public persuasion, and through the shaping of historic changes. This last is denied to all but those who find themselves at the right place at an epochal time. But on the first two scores, at least, Krugman may well become the first person outside the field of literature to win both the Nobel and Pulitzer Prizes, the acme of achievement in academics and journalism.

The dismal science has produced many versatile economists. Other giants of the 20th century, such as John Hicks, Ken Arrow, and Paul Samuelson, sparkled in several fields. Within international economics, though, specialization has tended to be the rule. Bertil Ohlin, Eli Hecksher, Jagdish Bhagwati, and Elhanan Helpman made seminal contributions in the field of international trade. International macroeconomics has seen many that fall somewhere between the great and the very good, including Robert Mundell, Rudi Dornbusch, Michael Mussa, Maurice Obstfeld, and Kenneth Rogoff.

But Krugman, like James Meade, is a rare economist whose accomplishments at the highest level span both of these subfields. He opened up the study of trade under increasing returns and imperfect competition and later resuscitated the study of economic geography. And his work on currency crises and exchange rates has been highly influential. In 1991, he was awarded the John Bates Clark medal in recognition of his "significant contribution to economic thought and knowledge." The cognoscenti know that this honor, which is awarded once every two years to an economist under 40, is a little more difficult to win than the annually awarded Nobel Prize.

Then there is Krugman the communicator. From writing "Greek letter" academic papers, he moved on to conveying economic ideas to the wider world (see Box 1). His Age of Diminished Expectations and Peddling Prosperity filled the gap between the boringly descriptive genre of "up-and-down economics" books and sensationalist and shallow "airport economics" books. Age of Diminished Expectations, commissioned by the Washington Post, ended up being not just an analysis of the U.S. economy in the postwar period but also a cracklingly lucid primer on international economics. Peddling Prosperity was an incisive and opinionated account of the history of economic ideas. Both books also worked as parables, illustrating Keynes's nostrum that the use and abuse of ideas are the most "dangerous for good and evil."

Krugman as public persuader was so successful that the New York Times offered him an op-ed column, the most prestigious piece of real estate in mainstream U.S. journalism. Almost by accident, he moved from demystifier of arcane economics to hard-hitting political commentator. One of his former teachers, Jagdish Bhagwati, tells F&D, "We were all pleasantly surprised that Krugman has been able to play the Mike Moore of the economics profession." Another teacher, Nobel Laureate Robert Solow, calls his former student "an all-purpose pest to the Bush administration." To many on the right, Krugman has seemed a shrill partisan who makes repetitious whining his stock-in-trade. But to others, he is now a cult figure: a brilliant and prescient analyst and, more important, a man of courage who stepped up to the plate in the aftermath of 9/11, when his fellow journalists became derelict in their duty to question, probe, and dissent.

Powerful ideas

Born in 1953, Krugman grew up in the New York suburbs, earning an undergraduate degree from Yale and a Ph.D. from the Massachusetts Institute of Technology (MIT). Although initially drawn to history, he soon embraced economics because, as he has put it, while history could answer the how and when, economics could answer the why.

A 1978 conversation with his teacher Rudi Dornbusch sparked a decision to work on increasing returns—the notion that a firm's unit costs decrease as its scale of production increases—marking a defining moment in his career. At Boston's Logan Airport a few months later, the eureka moment came when he cracked the mathematical problem of incorporating increasing returns and imperfect competition into trade models. In the summer of 1979, he presented his results at the Summer Institute of the U.S. National Bureau of Economic Research. "It was the happiest 90 minutes of my life," he tells F&D. He knew he had wowed his demanding peers.

Krugman believes that this breakthrough is his biggest achievement. The idea of increasing returns has been around in economics at least since Adam Smith, as has the inference that competition and international trade are affected by it: in particular, increasing returns are incompatible with the assumption of perfect competition that forms a basis of traditional trade theory. Krugman was one of the first economists to incorporate increasing returns and imperfect competition explicitly in trade models (he notes that these ideas were developed simultaneously but independently by two other researchers, Victor Norman and Kelvin Lancaster). This move represented a radical departure. Indeed, it was so radical that one of his early papers was rejected by the top journals, but Bhagwati, playing editor as deus ex machina, published it in the Journal of International Economics despite the verdict of two very negative referees.

Krugman's increasing returns papers were powerful partly because they explained a simple but uncomfortable fact about international trade: in the postwar period, a large and increasing share of trade occurred not between rich and poor countries but among the rich, and involved countries importing and exporting similar goods like cars, machines, and cereals, the so-called phenomenon of two-way trade. Such trade between countries with similar endowments is difficult to reconcile with traditional trade theory. But increasing returns showed that countries could specialize in different varieties of goods, leading countries to simultaneously export and import different varieties of similar goods.

From the confines of positive economics ("what is"), the theory of increasing returns was developed and extended into normative ("what ought to be") terrain by Krugman (along with Helpman, Barbara Spencer, James Brander, and others) as the strategic trade theory. This extension led to controversial policy conclusions that appeared to support government intervention, contributing to perceptions of a certain schizophrenia in Krugman's position on free trade (see Box 2).

On the macroeconomic front, Krugman developed the "first generation model" that locates the causes of currency crises in unsustainable government policies. Borrowing both the idea and the mathematical technique from the commodity price stabilization literature, he showed how and when a pegged exchange regime would be subject to a fatal speculative attack by investors. When the paper was first written, MIT's Dornbusch did not fully understand it—nor, apparently, did others because it found a home only in a lesser journal. Krugman faults the paper's craftsmanship and wishes he had written it differently. Still, it has come to be hailed as a groundbreaking study. Krugman also deserves credit for outlining the basics of the "third generation model" of currency crises, in which unhedged foreign currency liabilities play a large role in causing and transmitting crises.

Krugman's exploration of currency target zones in the late 1980s was considered clever and published in the prestigious Quarterly Journal of Economics. History's verdict has, however, been less generous, in part because the study's key prediction—that currencies stabilize as they approach the extremes of the target zones—has not found empirical support.

Similarly, Krugman's pioneering work on trade and geography, which showed a lot of early promise and continues to spawn an industry of academic papers (it is his most frequently cited work), has not quite caught fire in the broader public debate. Again, the key idea about external economies—the benefits to one firm of activities by another firm—had been described by the Cambridge economist and teacher of Keynes, Alfred Marshall. But Krugman found a way of formalizing this idea and derived some interesting implications, namely, that spatial patterns of development can be arbitrary and that historical accidents can have long-lasting effects. Silicon Valley (near San Francisco) and Route 128 (near Boston), both U.S. technological centers, are classic cases of agglomerations having idiosyncratic origins.

It is one of the ironies of Krugman the economist that for someone who said, "The point . . . is to wear one's technique lightly," his biggest contribution may well be that he provided the technique or language for discussing economic ideas and problems rigorously and sensibly. The contribution was immense because it allowed powerful ideas such as increasing returns and external economies, which had been around for some time, to be mainstreamed. It allowed models to replace metaphors as the basis for analysis. Without models, "guesswork is all that we have to go on, and those who discipline their guesses with models are more reliable than those who fly by the seat of their pants, no matter how well tailored." Krugman's style of building mathematical models is famously spartan and simple and occasionally even simplistic in its assumptions. But his sharp wielding of Occam's Razor (the principle that explanations should be as simple as possible) was so successful that the term "Krugmanesque" may yet enter the economics lexicon as the standard to which mathematical models aspire.

Economist as pundit

Krugman's academic output, unlike that of some others, did not head dramatically south after the John Bates Clark award. But the frenetic pace did slow down because, as he explains honestly, "You begin to wonder about the value of yet another paper even if it finds its way into a good journal. You also begin to doubt your ability to be creative and come up with really big, lasting ideas." And with his reputation as a communicator starting to soar, academia perhaps took a natural backseat.

Over the past five years, Krugman the columnist has overshadowed Krugman the economist. Has it been worth it? Krugman accepted the New York Times offer late in 1999, very much expecting to continue the vocation he had stumbled into over the years of writing on economics for the general public. Indeed, his initial columns were focused largely on such standard economics fare as the new economy, globalization, and fiscal deficits.

But after 9/11, and especially after the war began in Iraq, Krugman judged that his comparative advantage had shifted from being an economist to being a political commentator. He was willing to see things differently because he was not an insider infected by groupthink or the "contagion of mutual imitation" (as the Indian poet Rabindranath Tagore put it). The typical insider ("the commentariat") needs "sources" to get information, becomes compromised, and hence is less prone to ruffling feathers. Krugman, by contrast, had the comparative advantage of distance from Washington, D.C., and a full-time job that gave him the independence to be "unrestrained by deference," he explains. He could also do the "budget arithmetic" on his own. So, to him, the normal journalistic ethic of balance and moderation, which he disparagingly dubs "he-said-she-said journalism," was less a virtue than an intellectual shortcoming—an unwillingness or inability to process information independently and come to considered conclusions.

Krugman counts a number of successes in his stint as a journalist: revealing market manipulation by insiders as the real cause of the California energy crisis some years before anyone else; challenging Alan Greenspan's iconic status when he appeared to bless the Bush administration's tax cuts ("Et tu, Alan?" was the title of one of his columns); and exposing weaknesses in the economic policies and arguments of what he calls the Bush administration's "fuzzy math." The broader success, in his estimation, is a sense of vindication because his opinions, considered beyond the pale in the years following 2001, have now become mainstream. But Krugman thinks he might have paid too high a personal cost in enduring the personal and professional attacks on his credibility for his political writings. Gone are the days when his biggest worry was the state of his basement.

The reaction of some fellow economists to Krugman the columnist is often, "Ah, when Krugman used to be Krugman," combining a wistfulness for his brilliance with doubts about his current polemics. Solow calls Krugman's decision to become a full-time columnist a "big sacrifice" because he believes his former student has "so much good economics still left in him."

Does Krugman the economist have any regrets? He wishes he had done a greater amount of serious empirical work. He also wishes he had produced some really great students, a tribute to his own mentors—including Bhagwati, Dornbusch, Solow, Bill Nordhaus, and James Tobin. At Princeton University, which is his home after years at MIT, he says he is being a good citizen, taking on a full load of teaching. But he does not regret missing out on a White House post in 1992 (see Box 3) and doubts he will ever want to be a full-time Washington policymaker. "I just don't have the right temperament, I don't want to wear a suit every day, and anyway, I think I do more good on the outside."

Krugman's abiding belief, like that of Keynes, is that ideas matter and matter a lot. The role of public intellectuals is less to come up with good ideas, which is fiendishly hard, but more to serve as a watchdog to get rid of bad ideas and prevent their coming back. There are more bad ideas and more purveyors of bad ideas than their benign counterparts. And the asymmetry is further compounded because, in Yeats's words, "The best lack all conviction, while the worst are full of passionate intensity." In Paul Krugman, we have the very best, with conviction and passion, rendering the struggle between good and bad ideas, and between disputation and acceptance, a little less unequal.