Ronald Coase received the Nobel Prize in 1991 “for his discovery and clarification of the significance of transaction costs and property rights for the institutional structure and functioning of the economy.” Coase is an unusual economist for the twentieth century, and a highly unusual Nobel Prize winner. First, his writings are sparse. In a sixty-year career he wrote only about a dozen significant papers—and very few insignificant ones. Second, he uses little or no mathematics, disdaining what he calls “blackboard economics.” Yet his impact on economics has been profound. That impact stems almost entirely from two of his articles, one published when he was twenty-seven and the other published twenty-three years later.

Coase conceived of the first article, “The Nature of the Firm,” while he was an undergraduate on a trip to the United States from his native Britain. At the time he was a socialist, and he dropped in on perennial Socialist Party presidential candidate Norman Thomas. He also visited Ford and General Motors and came up with a puzzle: how could economists say that Lenin was wrong in thinking that the Russian economy could be run like one big factory, when some big firms in the United States seemed to be run very well? In answering his own question, Coase came up with a fundamental insight about why firms exist. Firms are like centrally planned economies, he wrote, but unlike the latter they are formed because of people’s voluntary choices. But why do people make these choices? The answer, wrote Coase, is “marketing costs.” (Economists now use the term “transaction costs.”) If markets were costless to use, firms would not exist. Instead, people would make arm’s-length transactions. But because markets are costly to use, the most efficient production process often takes place in a firm. His explanation of why firms exist is now the accepted one and has given rise to a whole literature on the issue. Coase’s article was cited 169 times in academic journals between 1966 and 1980.

“The Problem of Social Cost,” Coase’s other widely cited article (661 citations between 1966 and 1980), was even more pathbreaking; indeed, it gave rise to the field called law and economics. Economists before Coase of virtually all political persuasions had accepted British economist Arthur Pigou’s idea that if, say, a cattle rancher’s cows destroy his neighboring farmer’s crops, the government should stop the rancher from letting his cattle roam free or should at least tax him for doing so. Otherwise, believed economists, the cattle would continue to destroy crops because the rancher would have no incentive to stop them.

But Coase challenged the accepted view. He pointed out that if the rancher had no legal liability for destroying the farmer’s crops, and if transaction costs were zero, the farmer could come to a mutually beneficial agreement with the rancher under which the farmer paid the rancher to cut back on his herd of cattle. This would happen, argued Coase, if the damage from additional cattle exceeded the rancher’s net returns on these cattle. If, for example, the rancher’s net return on a steer was two dollars, then the rancher would accept some amount over two dollars to give up the additional steer. If the steer was doing three dollars’ worth of harm to the crops, then the farmer would be willing to pay the rancher up to three dollars to get rid of the steer. A mutually beneficial bargain would be struck.

Coase considered what would happen if the courts made the rancher liable for the damage caused by his steers. Economists had thought that the number of steers raised by the rancher would be affected. But Coase showed that the only thing affected would be the wealth of the rancher and the farmer; the number of cattle and the amount of crop damage, he showed, would be the same. In the above example, the farmer would insist that the rancher pay at least three dollars for the right to have the extra steer roaming free. But because the extra steer was worth only two dollars to the rancher, he would be willing to pay only up to two dollars. Therefore, the steer would not be raised, the same outcome as when the rancher was not liable.

This insight was stunning. It meant that the case for government intervention was weaker than economists had thought. Yet Coase’s soulmates at the free-market-oriented University of Chicago wondered, according to George Stigler, “how so fine an economist could make such an obvious mistake.” So they invited Coase, who was then at the University of Virginia, to come to Chicago to discuss it. They had dinner at the home of Aaron Director, the economist who had founded the Journal of Law and Economics.

Stigler recalled:

We strongly objected to this heresy. Milton Friedman did most of the talking, as usual. He also did much of the thinking, as usual. In the course of two hours of argument the vote went from twenty against and one for Coase to twenty-one for Coase. What an exhilarating event! I lamented afterward that we had not had the clairvoyance to tape it.1

Stigler himself labeled Coase’s insight the Coase theorem.

Of course, because transaction costs are never zero and sometimes are very high, courts are still needed to adjudicate between farmers and ranchers. Moreover, strategic behavior by the parties involved can prevent them from reaching the agreement, even if the gains from agreeing outweigh the transactions costs.

So, why were economists so excited by the Coase theorem? The reason is that it made them look differently at many issues. Take divorce. University of Colorado economist H. Elizabeth Peters showed empirically that whether a state has traditional barriers to divorce or divorce on demand has no effect on the divorce rate. This is contrary to conventional wisdom but consistent with the Coase theorem. If the sum of a couple’s net gains from marriage, as seen by the couple, is negative, then no agreement on distributing the gains from the marriage can keep them together. All the traditional divorce law did was enhance the bargaining position of women. A husband who wanted out much more than his wife wanted him in could compensate his wife to let him out. Not surprisingly, divorce-on-demand laws have made women who get divorces financially worse off, just as the absence of liability for the rancher in our example made the farmer worse off.

Coase also upset the apple cart in the realm of public goods. Economists often give the lighthouse as an example of a public good that only government can provide. They choose this example not based on any information they have about lighthouses, but rather on their a priori view that lighthouses could not be privately owned and operated at a profit. Coase showed, with a detailed look at history, that lighthouses in nineteenth-century Britain were privately provided and that ships were charged for their use when they came into port.

Coase earned his doctorate from the University of London in 1951 and emigrated to the United States, where he was a professor at the University of Buffalo from 1951 to 1958, at the University of Virginia from 1958 to 1964, and at the University of Chicago from 1964 to 1979, when he retired.

See also: externalities.

About the Author

David R. Henderson is the editor of The Concise Encyclopedia of Economics. He is also an emeritus professor of economics with the Naval Postgraduate School and a research fellow with the Hoover Institution at Stanford University. He earned his Ph.D. in economics at UCLA.

Selected Works

1937. “The Nature of the Firm.” Economica 4 (November): 386–405.
1938. “Business Organization and the Accountant.” Reprinted in James M. Buchanan and G. F. Thirlby, eds., L.S.E. Essays on Cost. London: Weidenfeld and Nicolson, 1973. Available online at:
1959. “The Federal Communications Commission.” Journal of Law and Economics 2 (October): 1–40.
1960. “The Problem of Social Cost.” Journal of Law and Economics 3 (October): 1–44.
1974. “The Lighthouse in Economics.” Journal of Law and Economics 17, no. 2: 357–376.


1. George Stigler, Memoirs of an Unregulated Economist (New York: Basic Books, 1988), p. 76.

Related Entries

Related Links

A Conversation with Ronald Coase, an Intellectual Portrait at Econlib.

Ronald Coase on Externalities, the Firm, and the State of Economics, an EconTalk podcast, May 21, 2012.

Pedro Schwartz, Ronald Coase: the Unexpected Economist, at Econlib, October 7, 2013.

Pedro Schwartz, The Poverty of Social Choice, at Econlib, November 2, 2015.

Peter Boettke, The Role of the Economist in a Free Society: Friedman to Coase, at Econlib, August 5, 2019.

Rosolino Candela, Ronald H. Coase: Chicago School or Virginia School Economist? at EconLog, July 6, 2020.

Don Boudreaux on Coase, an EconTalk podcast, October 28, 2013.

Robert Frank on Coase, an EconTalk podcast, February 24, 2014.

Michael Munger on the Nature of the Firm, an EconTalk podcast, January 14, 2008.