Tim Worrall

• Doctor of Philosophy
• Professor at University of Edinburgh

How should successive generations insure each other when the young can default on previously promised transfers to the old? This paper studies intergenerational insurance that maximizes the expected discounted utility of all generations subject to participation constraints for each generation. If complete insurance is unattainable, the optimal inte...

Fiscal integration is recognized as an important issue in determining whether countries establish a common currency area. Fiscal integration between sovereign states is, however, limited by the ability of countries to commit to fiscal transfers. This paper supposes that fiscal transfers between countries must be voluntary and asks how this influenc...

This paper extends the DeMarzo and Duffie (1999) signaling model from single sales to portfolio sales. It shows that the extended model can account for retention of low quality assets and help explain why retained assets may be of varying quality.

In this paper, we study the costs and benefits of the adoption of a policy of free movement of workers. For countries to agree on uncontrolled movements of workers, short-run costs must be outweighed by the long-term benefits of better labor-market flexibility and income smoothing. We show that such a policy is less likely to be adopted when worker...

We introduce and analyse a new class of monotone stochastic recur- sions in a regenerative environment which is essentially broader than that of Markov chains. We prove stability theorems and apply our results to two canonical models in recursive economics, generalising some known stability results to the cases when driving sequences are not indepe...

This paper considers a long-term relationship between two agents who both undertake a costly action or investment that together produces a joint benefit. Agents have an opportunity to expropriate some of the joint benefit for their own use. Two cases are considered: (i) where agents are risk neutral and are subject to limited liability constraints...

This paper considers a long-term relationship between two agents who undertake costly actions or investments which produce a joint benefit. Agents have an opportunity to expropriate some of the joint benefit for their own use. The question asked is how to structure the investments and division of the surplus over time so as to avoid expropriation....

This paper considers a simple stochastic model of international trade with three countries. Two of the tree countries are in an economic union. Comparisons are made between equilibrium welfare for these two countries under fixed and flexible exchange rate regimes. Within the model it is shown that flexible exchange rate regimes generate greater wel...

We present an overview of models of long-term self-enforcing labour contracts in which risk-sharing is the dominant motive for contractual solutions. A base model is developed that is sufficiently general to encompass the two-agent problem central to most of the literature, including variable hours. We consider two-sided limited commitment and look...

This paper reports on available bibliometric evidence on the performance of UK research in economics. It examines some standard and non-standard sources of bibliometric evidence and in particular evidence from the ISI and EconLit databases and the Repository of Papers in Economics (RePEc). It also reports on research capacity of UK economics and so...

This paper analyzes a model of private unemployment insurance under limited commitment and a model of public unemployment insurance subject to moral hazard in an economy with a continuum of agents and an infinite time horizon. The dynamic and steady-state properties of the optimum private unemployment insurance scheme are established. The interacti...

We introduce a new hybrid approach to joint estimation of Value at Risk (VaR) and Expected Shortfall (ES) for high quantiles of return distributions. We investigate the relative performance of VaR and ES models using daily returns for sixteen stock market indices (eight from developed and eight from emerging markets) prior to and during the 2008 fi...

In this paper, we consider the Coase theorem in a non cooperative game framework. In particular, we explore the robustness of the Coase theorem with respect to the ?nal distribution of alienable property rights which constitutes, as far as we know, a less cultivated ?eld of research. In our framework, in order to reach e� ciency, agents have to sti...

This paper analyses a model of private unemployment insurance under limited commitment and a model of public unemployment insurance subject to moral hazard in an economy with a continuum of agents and an infinite time horizon. The dynamic and steady-state properties of the private unemployment insurance scheme are established. The interaction betwe...

Recent work on consumption allocations in village economies finds that idiosyncratic variation in consumption is systematically related to idiosyncratic variation in income, thus rejecting the hypothesis of full risk-pooling. We attempt to explain these observations by adding limited commitment as an impediment to risk-pooling. We provide a general...

The fluctuations in incomes inherent in rural communities can be attenuated by reciprocal assistance. A model of reciprocal assistance based upon rational action and voluntary participation is presented. Individuals provide assistance only if the costs of so doing are outweighed by the benefits from expected future reciprocation. A distinction is m...

In this paper we consider a regulated monopoly that can pad its costs to increase its cost reimbursement. Even while padding is ine#cient the optimal incentive scheme tolerates some padding of costs to reduce the information rents paid to low cost types. It is shown that high cost firms pad costs more than low cost firms. We also show that cost pad...

It is shown how intergenerational risk sharing can be achieved by transfers from the young generation to the old generation such that the young generation will never have an incentive to unilaterally renege on the transfer. This contradicts a claim made in Gordon and Varian (1988).

We examine a dynamic model of mutual insurance when households can also engage in self insurance by storage. We assume that there is no enforcement mechanism, so that any insurance is informal, and must be self-enforcing. We show that consumption allocations satisfy a modified Euler condition and that an enhanced storage technology can either impro...

[eng] Transportation costs and monopoly location in presence of regional disparities. . This article aims at analysing the impact of the level of transportation costs on the location choice of a monopolist. We consider two asymmetric regions. The heterogeneity of space lies in both regional incomes and population sizes: the first region is endowed...

This book focuses on the rapidly growing research field of imperfect competition, asymmetric information, and other market imperfections in a macroeconomic context. It brings together leading researchers from the USA and Europe to examine the implications for macroeconomic policy of market imperfections in output, labour and financial markets. All...

Rationing is a pervasive feature of credit markets. It has been suggested that credit rationing represents a suboptimal allocation of resources. In a general equilibrium model of credit rationing with hidden information and costly monitoring we show that if credit is rationed it is suboptimal but that credit should be rationed more tightly. In equi...

When a transnational corporation invests abroad, it runs the risk that its investment will be expropriated. Any agreements or contracts undertaken by the transnational company and the host country must be designed to be self-enforcing. This paper extends previous work on investment when contracts are incomplete to a dynamic context. It is shown tha...

Lending across national boundaries is different from lending within national boundaries because of the difficulty of imposing legal sanctions. This paper examines a simple model of international lending where the borrower can repudiate, without legal sanction, if this is to his advantage. The model has an infinite time horizon and it is assumed the...

We examine a simple repeated principal-agent model with discounting. There are a risk averse borrower with an unobservable random income and a risk neutral lender. The efficient contract is characterized. It tends to the first-best (constant consumption) contract as the discount factor tends to one and the time horizon extends to infinity. If the t...

We examine long-term wage contracts between a risk-neutral firm and a risk-averse worker when both can costlessly renege and buy or sell labour at a random spot market wage. A self-enforcing contract is one in which neither party ever has an incentive to renege. In the optimum self-enforcing contract, wages are sticky: they are less variable than s...

This paper considers a long-term relationship between two agents who undertake costly actions or investments which produce a joint benefit. Each agent has an op- portunity to expropriate some of the joint benefit for his or her own use. The question asked is how to structure the investments and division of the surplus over time so as to avoid expro...

investments.

This paper considers a long-term relationship between two agents who undertake costly actions or investments which produce a joint benefit. Agents have an oppor- tunity to expropriate some of the joint benefit for their own use. The question asked is how to structure the investments and division of the surplus over time so as to avoid expropriation...

This paper considers whether countries might mutually agree a policy of open borders, allowing free movement of workers across countries. For the countries to agree, the short run costs must outweighed by the long term benefits that result from better labour market flexibility and income smoothing. We show that such policies are less likely to be a...

This paper surveys the literature on the role of financial factors in explaining economic fluctuations. We begin by discussing the views of some prominent early macroeconomists and then examine the recent literature on the role of asymmetric information in the market for investment finance. This literature shows that in the presence of informationa...