Karl Shell (born May 10, 1938) is an American theoretical

economist An economist is a professional and practitioner in the social sciences, social science discipline of economics. The individual may also study, develop, and apply theories and concepts from economics and write about economic policy. Within this ...

, specializing in

macroeconomics Macroeconomics is a branch of economics that deals with the performance, structure, behavior, and decision-making of an economy as a whole. This includes regional, national, and global economies. Macroeconomists study topics such as output (econ ...

and

monetary economics Monetary economics is the branch of economics that studies the different theories of money: it provides a framework for analyzing money and considers its functions (as medium of exchange, store of value, and unit of account), and it considers how m ...

. Shell received an A.B. in

mathematics Mathematics is a field of study that discovers and organizes methods, Mathematical theory, theories and theorems that are developed and Mathematical proof, proved for the needs of empirical sciences and mathematics itself. There are many ar ...

from

Princeton University Princeton University is a private university, private Ivy League research university in Princeton, New Jersey, United States. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial ...

in 1960. He earned his Ph.D. in

economics Economics () is a behavioral science that studies the Production (economics), production, distribution (economics), distribution, and Consumption (economics), consumption of goods and services. Economics focuses on the behaviour and interac ...

in 1965 at

Stanford University Leland Stanford Junior University, commonly referred to as Stanford University, is a Private university, private research university in Stanford, California, United States. It was founded in 1885 by railroad magnate Leland Stanford (the eighth ...

, where he studied under

Nobel Prize in Economics The Nobel Memorial Prize in Economic Sciences, officially the Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel (), commonly referred to as the Nobel Prize in Economics(), is an award in the field of economic sciences adminis ...

winner

Kenneth Arrow Kenneth Joseph Arrow (August 23, 1921 – February 21, 2017) was an American economist, mathematician and political theorist. He received the John Bates Clark Medal in 1957, and the Nobel Memorial Prize in Economic Sciences in 1972, along with ...

and Hirofumi Uzawa. Shell is currently Robert Julius Thorne Professor of

Economics Economics () is a behavioral science that studies the Production (economics), production, distribution (economics), distribution, and Consumption (economics), consumption of goods and services. Economics focuses on the behaviour and interac ...

Cornell University Cornell University is a Private university, private Ivy League research university based in Ithaca, New York, United States. The university was co-founded by American philanthropist Ezra Cornell and historian and educator Andrew Dickson W ...

(succeeding notable economist and airline deregulator

Alfred E. Kahn Alfred Edward Kahn (October 17, 1917 – December 27, 2010) was an American economist and political advisor who specialized in regulation and deregulation. He was an important influence in the deregulation of the airline and energy industries. ...

in the Thorne chair). He previously served on the economics faculty at

MIT The Massachusetts Institute of Technology (MIT) is a private research university in Cambridge, Massachusetts, United States. Established in 1861, MIT has played a significant role in the development of many areas of modern technology and sc ...

and the

University of Pennsylvania The University of Pennsylvania (Penn or UPenn) is a Private university, private Ivy League research university in Philadelphia, Pennsylvania, United States. One of nine colonial colleges, it was chartered in 1755 through the efforts of f ...

. Shell has been editor of the ''

Journal of Economic Theory The ''Journal of Economic Theory'' is a bimonthly peer-reviewed academic journal covering the field of economic theory. Karl Shell has served as editor-in-chief of the journal since it was established in 1968. Since 2000, he has shared the editor ...

'', generally regarded as the leading

journal A journal, from the Old French ''journal'' (meaning "daily"), may refer to: *Bullet journal, a method of personal organization *Diary, a record of personal secretive thoughts and as open book to personal therapy or used to feel connected to onesel ...

in theoretical economics, since its inception in 1968.

Contributions to economics

While Shell has published academic articles on numerous topics in economics, he is primarily known for his contributions in three areas. Between 1966 and 1973, Shell published three papers on inventive activity, increasing returns to scale,

industrial organization In economics, industrial organization is a field that builds on the theory of the firm by examining the structure of (and, therefore, the boundaries between) firms and markets. Industrial organization adds real-world complications to the per ...

, and

economic growth In economics, economic growth is an increase in the quantity and quality of the economic goods and Service (economics), services that a society Production (economics), produces. It can be measured as the increase in the inflation-adjusted Outp ...

. This contribution was important in its day, and later influenced the development of "new growth theory." Among others,

Paul Romer Paul Michael Romer (born November 6, 1955) is an American economist and policy entrepreneur who is a Seidner University Professor in Finance at Boston College. Romer is best known as the former Chief Economist of the World Bank and for co- ...

cited and heavily built upon Shell's work in his seminal papers on

endogenous growth theory Endogenous growth theory holds that economic growth is primarily the result of endogenous and not external forces. Endogenous growth theory holds that investment in human capital, innovation, and knowledge are significant contributors to economic ...

. Shell also made important contributions to the

overlapping generations In population genetics overlapping generations refers to mating systems where more than one breeding generation is present at any one time. In systems where this is not the case there are non-overlapping generations (or discrete generations) in wh ...

literature (and was perhaps the first to refer to the overlapping generations model by its modern name). The overlapping generations model is now a workhorse in modern macroeconomics and

. Karl Shell is also co-inventor (with

David Cass David Cass (January 19, 1937 – April 15, 2008) was a professor of economics at the University of Pennsylvania, mostly known for his contributions to general equilibrium theory. His most famous work was on the Ramsey–Cass–Koopmans model of ...

) of the concept of sunspot equilibrium (and

sunspots Sunspots are temporary spots on the Sun's surface that are darker than the surrounding area. They are one of the most recognizable Solar phenomena and despite the fact that they are mostly visible in the solar photosphere they usually affe ...

). Sunspot equilibrium provides a model for excess market volatility, including

bank runs A bank run or run on the bank occurs when many clients withdraw their money from a bank, because they believe the bank may fail in the near future. In other words, it is when, in a fractional-reserve banking system (where banks normally only ...

References

Publications

*Karl Shell, "Toward a Theory of Inventive Activity and Capital Accumulation", ''American Economic Review'', Vol. 56(2), May 1966, 62–68. *Karl Shell, "A Model of Inventive Activity and Capital Accumulation" in ''Essays on the Theory of Optimal Economic Growth'' (K. Shell, ed.), Cambridge, Massachusetts: MIT Press, 1967, Chapter IV, 67–85. *Karl Shell (Editor), ''Essays on the Theory of Optimal Economic Growth'', Cambridge, Massachusetts: MIT Press, 1967, (hardcover), 9780262690133(paperback). *Karl Shell, "Notes on the Economics of Infinity", ''Journal of Political Economy'', Vol. 79(5), September/October 1971, 1002–1011. *Karl Shell and Giorgio P. Szegö (Editor), ''Mathematical Methods in Investment and Finance'', Amsterdam: North-Holland, 1972. (North- Holland), 044410395 (American Elsevier). *Karl Shell and Franklin M. Fisher, ''The Economic Theory of Price Indices: Two Essays on the Effect of Taste, Quality, and Technological Change'', New York: Academic Press, 1972. . *Karl Shell, "Inventive Activity, Industrial Organization and Economic Growth" in ''Models of Economic Growth'' (J.A. Mirrlees and N. Stern, eds.), London: Macmillan, and New York: Halsted (John Wiley & Sons), 1973, 77–100. *Karl Shell and David Cass (Editor), ''The Hamiltonian Approach to Dynamic Economics'', New York: Academic Press, 1976. . *David Cass and Karl Shell, "Do Sunspots Matter?", ''Journal of Political Economy'', Vol. 91(2), April 1983, 193–227. *Karl Shell, William A. Barnett and John Geweke (Editor), ''Economic Complexity: Chaos, Sunspots, Bubbles, and Nonlinearity'', New York: Cambridge University Press, 1989. . *Karl Shell and Franklin M. Fisher, ''Economic Analysis of Production Price Index'', New York: Cambridge University Press (Hardcover, , and soft cover, ), 1998. *Karl Shell, "Sunspot Equilibrium", ''The New Palgrave: A Dictionary of Economics, 2nd Edition'' (L. Blume and S. Durlauf, eds.), New York: Palgrave Macmillan, 2008.

External links

*Karl Shell Web Page: http://www.karlshell.com. * *''Journal of Economic Theory'' Web Page: http://jet.arts.cornell.edu/Main.html. * * *Karl Shell CV: http://karlshell.com/wp-content/uploads/2021/07/CV-June-25-2021-4.pdf {{DEFAULTSORT:Shell, Karl American economists 1938 births Living people Fellows of the Econometric Society