Tim Worrall • Professor of Economics • The University of Edinburgh

II Research

Research Interests My principal research interests (with corresponding JEL classification) are: Game Theory and Bargaining Theory (C7) • Market Structure and Pricing (D4) • Information and Uncertainty (D8) • Intertemporal Choice and Growth (D9) • Consumption, Saving, Production, Employment and Investment (E2) • Financial Markets (G1) • Corporate Finance and Governance (G3) • Regulation and Industrial Policy (L5). My main areas of current research are in limited commitment, principal-agent problems and contract theory, risk and uncertainty and network design.
Research Grants Leverhulme Trust Fellowship, "Intergenerational Insurance", (55k), • January 2024 - December 2024 • Economic and Social Research Council, one of several Co-Investigators on Large Grant "Credit and Labour Market Foundations of the Macroeconomy" with John Hardman-Moore (Principal Investigator), 6 million, June 2015 - June 2020 • Royal Economic Society award on "Evaluating the Research Performance of UK Economics" with Gauthier Lanot, 12k, September 2006 - December 2006 • Economic and Social Research Council award on "Dynamic Relational and Self-Enforcing Contracts" with Jonathan Thomas (Principal Investigator), 151k, January 2005 - December 2006 • Department for International Development award on "The effects of macro-financial liberalisation policies on micro-household savings and credit behaviour in developing countries" with Peter Lawrence (Principal Investigator), Robin Bladen-Hovell, and Gauthier Lanot, 145k, April 2001 - March 2003 • Leverhulme Trust Fellowship, "Quasi-credit in less developed countries", 15k, 1998-9 • Keele Research Incentive Scheme, "Quasi-credit and LDCs", 5k, January 1989 - December 1989.
Research Collaborators Spiros Bougheas (University of Nottingham)
Sergio Cappellini (University of Padua)
Martin Diedrich (University of Bristol)
Sergey Foss (Heriot-Watt University)
Francesco Lancia (Ca' Foscari University of Venice)
Gauthier Lanot (Umeå University)
Ethan Ligon (University of California at Berkeley)
Costas Milas (University of Liverpool)
Pierre Picard (University of Luxembourg and CORE, Louvain-la-Neuve)
Alessia Russo (University of Padua)
Seva Shneer (Heriot-Watt University)
Jonathan Thomas (University of Edinburgh)
Nicholas Vasilakos (University of East Anglia)
Robert Zymek (International Monetary Fund)
PhD Students Sikandar Singh Soin (Data Analyst, Ministry of Justice, Edinburgh), graduated University of Edinburgh, 2022.
Pongpalin Yingchoncharoen (Lecturer, Thammasat University, Thailand), graduated with MRes in Economics, University of Edinburgh, 2018.
Aodi Tang (Economist, UBS, London), graduated University of Edinburgh, 2018.
Rongyu Wang (Lecturer, Shandong University of Arts, China), graduated University of Edinburgh, 2016.
Sareh Vosooghi (Assistant Professor, Department of Economics, KU Leuven, Belgium), graduated University of Edinburgh, 2016.
Vasco Filipe de Figueiredo Alves (Assistant Professor in Economics, University of Birmingham), graduated University of Edinburgh, 2016.
Michael King (Lead, Analysis and Evaluation Team, National Physical Laboratory, London), graduated University of Manchester, 2011.
Ioannis Lazopoulos (Senior Lecturer in Economics, University of Surrey), graduated Keele University, 2006.
Alex Dickson (Reader in Economics, University of Strathclyde, Glasgow), graduated Keele University, 2005.
Svetlana Andrianova (Associate Professor in Economics, University of Leicester), graduated London South Bank University, 2001.
Research Overview Much of my work has been on limited commitment. Limited commitment occurs when contracts or agreements cannot be perfectly enforced. Most economic contracts have limited commitment. Examples, in particular, are to be found between countries, where there is no supranational legal framework, and in less developed countries, where there is a weaker legal framework. A key result of this work is to show that in order to provide incentives for the parties to provide information or comply with the contract, the temporal structure of the contract will be non-stationary even when the underlying environment itself is not changing over time. The literature in this area has focussed on two motivations for contracting: either risk-sharing or joint production. Together with Jonathan Thomas, I have made contributions to both areas of this literature. In a recent paper, we bring both motivations together to consider a single unified framework
Current Projects A current project (joint with Francesco Lancia and Alessia Russo) examines intergenerational insurance. The aim of the project is to provide a theoretical study of insurance between generations. Insurance provision is constrained by the need for it to be voluntary or politically sustainable: no young generation will provide insurance unless the expected future benefits at least compensate the current cost. To put in a contemporary UK context, can the triple lock on pensions be sustained if an increasing share of resources go to the old. More generally, the project studies how shocks to one generation are shared with future generations and how transfers between generations depend on the history of past shocks.

The work considers a standard two-period, overlapping generations, one-good, endowment economy with uncertainty and limited commitment. It considers a benevolent planner that chooses history-contingent transfer from the young to the old subject to the voluntary participation constraint. The existence of a set of transfers that improves on autarky is well-known and depends on an eigenvalue property of the relevant state-price matrix. Absent either risk or limited commitment, the long run distribution of consumption is degenerate even when the existence condition is satisfied. However, with risk and binding limited commitment constraints, there is convergence of the efficient transfers to a unique non-degenerate distribution on a endogenous but countable state space. This property is derived from the stochastic stability results for regenerative processes. In a simple case, we can derive the distribution and its properties via a shooting algorithm.

It is possible to interpret the transfer to the old as either a pension in a state pay-as-you-go social security system or as a debt that is repaid to the old. The proposed research will consider both applications. With the first interpretation, the model implies that the pension received in old age depends on a measure of the contribution made when young. In the case of logarithmic preferences, this measure is the contribution rate, the contribution to the pension as a proportion of income. In this case, the pension is an increasing function of the past contribution rate above a certain threshold and independent of the past contribution rate below this threshold. Additionally, for each given contribution rate paid when young, the pension the old receive is inversely related to their own endowment. That is, the optimal pension scheme will have both means testing and a mixture of flat-rate and contributory-related elements. All three of these features are commonly found in national pension schemes. Absent enforcement issues, the optimal pension scheme has only flat-rate and means-testing elements and therefore, a key prediction is that the optimal pension scheme has a contributory-related element whenever payments into the pension are constrained to be voluntary. Alternatively, the transfer to the old can be interpreted as debt. If preferences are logarithmic, there is a simplification in interpreting debt as the share of transfer relative to the endowment of the young. In this case, state-contingent bonds sell at the appropriate state prices. This generates a bond revenue for the planner and the planner taxes or subsidises the young to fund the inherited debt. This generates a fiscal reaction function that specifies the tax as a function of the inherited debt. The fiscal reaction function is non-linear and may exhibit fiscal fatigue at high levels of debt. The risk premium on debt is below the agregate risk premium because debt acts as a hedge against risk, providing a potential explanation for the debt valuation puzzle. Moreover, the risk premium on debt varies with debt and evolves with the evolution of debt. In a two-state example, the gap between the aggregate risk premium and the risk premium on debt declines with debt.
Talks and Presentations
  • Society for Economic Measurement, Atlanta, Georgia, August 2014
  • Durham University, January 2024
  • Royal Economic Society, Belfast, April 2021
  • European Meeting of the Econometric Society, Manchester, August 2019
  • National Bureau of Economic Research Summer Institute (Macro Public Finance Research Group), Boston, July 2017
  • Society for the Advancement of Economic Theory, Faro, June 2017
  • Society for Economic Dynamics, Edinburgh, June 2017
  • Umeå University, Sweden, February 2017
  • Theoretical Research in Development Economics conference, Duke University, April 2016
  • Heriot-Watt University, November 2015
  • Society for the Advancement of Economic Theory, Cambridge, July 2015
  • University of Hull, February 2015
  • Durham University, September 2014
  • University of Manchester, September 2014
  • University of Liverpool, November 2013
  • University of Oslo, Oslo, Norway, September 2013
  • Yonsei University, Seoul, Korea, June 2013
  • York Game Theory Symposium, University of York, June 2013
  • Workshop on macroeconomic applications of dynamic games and contracts, Stony Brook, New York, July 2012
  • Journées d'Economie Publique Louis-André Gérard-Varet, Marseilles, June 2012
  • Keele University, February 2012
  • University of Strathcylde, Glasgow, February 2012
  • City University of London, January 2012
  • Durham University, October 2011
  • European Trade Study Group, Copenhagen, September 2011
  • Society for Economic Dynamics, Ghent, July 2011
  • Society for the Advancement of Economic Theory, Faro, June 2011
  • Econometric Society Winter Meetings, Denver, January 2011
  • Transnationality of Migrants (TOM) Workshop on Frontiers of Migration Research, Bamberg, July 2010
  • University of Dundee, March 2010
  • University of Surrey, November 2009
  • Workshop on the Theory and Empirics of Risk Sharing, Gremaq, Toulouse School of Economics, October 2009
  • Society for Economic Dynamics, Istanbul, July 2009
  • Canadian Economic Association, Toronto, May 2009
  • Workshop of the Regional Studies Research Network on Geographical Localisation, Intersectoral Reallocation of Labour and Unemployment Differentials, Rimini, May 2009
  • University of Warwick, November 2008
  • 2nd Workshop in Applied Microeconomics, University of St Andrews, September 2008
  • Society for Economic Dynamics, Massachusetts Institute of Technology, July 2008
  • Canadian Macroeconomic Study Group, Ottawa, November 2007
  • Durham University, November 2007
  • Workshop on Risk Sharing, Gremaq, Toulouse School of Economics, September 2007
  • University of Bristol, May 2007
  • University of Sheffield, May, 2007
  • Econometric Society European Meetings, Vienna, August 2006
  • European Economic Association, Vienna, August 2006
  • Canadian Economic Association, Montreal, May 2006
  • Royal Economic Society, Nottingham, April 2006
  • University of California at Berkeley, March 2006
  • Manchester University, February 2006
  • Workshop on Limited Commitment, University of Edinburgh, November 2005
  • Society for Economic Dynamics, Budapest, June 2005
  • European Economic Association, Madrid, August 2004
  • Queen's University Belfast, May 2004
  • University of Birmingham, May 2004
  • Durham University, November 2003
  • Econometric Society European Meetings, Stockholm, August 2003
  • Game Theory Workshop, University of Nottingham, April 2003
  • University of Newcastle, April 2003
  • Birkbeck College London, March 2002
  • University of Surrey, February 2002
  • Econometric Society European Meetings, Lausanne, August 2001
  • South Bank University, May 2000
  • University of Nottingham, May 2000
  • University of Birmingham, November 1999
  • European Congress of the Econometric Society, Santiago de Compostela, Spain, 1999
  • Department of Agricultural Resource Economics, University of California at Berkeley, April 1999
  • Durham University, 1997
  • University of Liverpool, June 1996
  • University of Loughborough, May 1996
  • Institute for Empirical Macroeconomics at the Federal Reserve Bank of Minneapolis, Minnesota, April 1996
  • 7th World Congress of the Econometric Society, Tokyo, 1995
  • University of Manchester, 1995
  • Summer Research Workshop on New Macroeconomics, University of Warwick, July 1994
  • University of Sheffield, 1994
  • Keele University, 1994
  • Aberystwyth University, 1993
  • University of Exeter, 1993
  • University of Salford, Manchester, 1993
  • 1st Summer School in Economic Theory at La Sorbonne, Paris, April 1993
  • Centre for Operations Research and Economics at the University of Louvain-la-Neuve, Belgium, April 1993
  • 6th World Congress of the Econometric Society in Barcelona, August 1990
  • European Congress of the Econometric Society, Budapest, August 1986
  • European Congress of the Econometric Society, Madrid, August 1984
Research Visits Department of Economics and Management - Marco Fanno (dSEA), University of Padua, May 2024 • Department of Agricultural Resource Economics, University of California at Berkeley, April-May 2012 • Department of Economics, University of Vienna, December 2011 • RECent (Center for Economic Research), Department of Political Economy, University of Modena and Reggio Emilia, May 2011 • Department of Agricultural Resource Economics, University of California at Berkeley, February-April 2006 • Institute for Empirical Macroeconomics, Federal Reserve Bank of Minneapolis, April 1996 • Centre for Operational Research and Economics, Louvain-la-Neuve, April 1992.
Peer Reviewing Carnegie Trust • British Academy • Economic and Social Research Council • Engineering and Physical Sciences Research Council • Leverhulme Trust • Nuffield Foundation • National Science Foundation, USA • Social Sciences and Humanities Research Council, Canada • The Austrian Science Fund, Austria.
Research Evaluation Member of the Economics and Econometrics Sub-panel for the UK Research Excellence Framework 2021 • Depertment of Economics, University of Exeter • Department of Economics, University of Bristol • Department of Economics and Related Studies, University of York • Department of Industrial Economics, University of Nottingham • Notingham Busines School, Nottingham Trent University.
Journal Refereeing American Economic Review • American Economic Review: Insights • Berkeley Electronic Journal of Theoretical Economics • Bulletin of Economic Research • Canadian Journal of Economics • Computational Economics • Ecological Economics • Economics Bulletin • Economic Inquiry • Economica • Economics: The Open-Access, Open-Assessment E-Journal • The Economic Journal • Econometrica • Economics Letters • Economic Theory • Education Economics • Ekonomia • Environmental and Resource Economics • European Economic Review • European Journal of Finance • European Journal of Political Economy • FinanzArchiv / Public Finance Analysis • International Economic Review • International Journal of Finance and Economics • Games and Economic Behavior • International Journal of Industrial Organization • International Sociology • International Tax and Public Finance • Journal of Development Economics • Journal of Development Studies • Journal of Economic Behavior and Organization • Journal of Economic Dynamics and Control • Journal of Economic Surveys • Journal of Economic Theory • Journal of the European Economic Association • Journal of Institutional and Theoretical Economics • Journal of International Economics • Journal of Labor Economics • Journal of Monetary Economics • Journal of Money, Credit and Banking • Journal of Pension Economics and Finance • Journal of Political Economy • Journal of Population Economics • Journal of Transport Economics and Policy • Managerial and Decision Economics • The Manchester School • Metroeconomica • Oxford Economic Papers • Rand Journal of Economics • Quarterly Journal of Economics • Review of Economic Dynamics • Review of Economic Studies • Review of Industrial Organization • Scandinavian Journal of Economics • Scottish Journal of Political Economy • Social Problems • Southern Economic Journal • Stochastic Processes and their Applications • Theoretical Economics.
Book Refereeing Addison Wesley • Cambridge University Press • Harper-Collins • MIT Press • Pearson Education.