Economics: An Emerging Small World?

63 Pages Posted: 8 Jun 2004

See all articles by Sanjeev Goyal

Sanjeev Goyal

University of Cambridge

Marco van der Leij

CeNDEF, University of Amsterdam; Tinbergen Institute; De Nederlandsche Bank - Research Department

José L. Moraga-González

VU University Amsterdam; University of Groningen

Date Written: September 2004


The structures of social interaction affect individual behavior and economic performance in important ways. This leads us to ask: does the architecture of social interaction exhibit particular patterns and are these patterns stable over time? We examine interaction among economists by looking at the evolution of co-authorship relations over a thirty-year period. We find that in the 1970's this world was quite fragmented, with the largest interconnected group - "the giant component" - covering only 15% of the population. However, by the 1990's economics was much more integrated, with the giant component covering over 40% of the population. The average distance between individuals was small and declined over the period, leading us to conclude that economics is an emerging small world. A crucial stable feature of the network over this period is the existence of several stars (economists with many co-authors each of whom have few collaborators and rarely work among themselves). The world of economics is thus a collection of inter-linked stars. We also find that a growth in the average number of co-authors is the main reason behind the growth in the giant component and the fall in average distances within it. The second part of the paper develops a simple theoretical model of collaboration in economics. We find that an unequal distribution of collaborations and inter-linked stars arise naturally in this environment. Falling costs of communication and increasing credit for joint research lead to greater co-authorship and this supports a larger giant component.

Keywords: Small world, economics research, networks, coauthorship, hierarchy

JEL Classification: A14, D20, J41, L22, O30

Suggested Citation

Goyal, Sanjeev and van der Leij, Marco Juri and Moraga-Gonzalez, Jose Luis, Economics: An Emerging Small World? (September 2004). CESifo Working Paper Series No. 1287; FEEM Working Paper No. 84.04; Tinbergen Institute Discussion Paper No. 04-001/1. Available at SSRN:

Sanjeev Goyal (Contact Author)

University of Cambridge ( email )

Trinity Ln
Cambridge, CB2 1TN
United Kingdom

Marco Juri van der Leij

CeNDEF, University of Amsterdam ( email )

Roetersstraat 11
Amsterdam, NL-1018WB
+31 20 525 7356 (Phone)


Tinbergen Institute ( email )

Burg. Oudlaan 50
Rotterdam, 3062 PA

De Nederlandsche Bank - Research Department ( email )

P.O. Box 98
1000 AB Amsterdam

Jose Luis Moraga-Gonzalez

VU University Amsterdam ( email )

De Boelelaan 1105
1081 HV Amsterdam


University of Groningen

P.O. Box 800
9700 AV Groningen, Groningen 9700 AV

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