On PPP,unit roots and panels

In this paper we use a combination of time series unit root and cointegration analysis and the Bai and Ng (Econometrica 72:1127–1187, 2004) factor model approach to assess the purchasing power parity hypothesis for four real exchange rate panels. Our main findings are twofold: First, we find robust evidence for nonstationary common components in the real exchange rate panels and hence no evidence for PPP. Second, the presence of nonstationary common components is consistent with rejections of the unit root null hypothesis when applying a battery of first and second generation panel unit root tests, which are known to be adversely affected in the presence of common nonstationary components.     

Accounting for Stability

There is no consensus about the causes of the reduction in businesscycle volatility seen in many major economies over the lastdecade. Using stylised models of the economies of the US, Euroarea, UK and Japan, we argue that economic stability has beenfostered by improved monetary policy and by associated changesin the behaviour of inflation, which has itself led to a reductionin the volatility of economic shocks. Our projections suggestthat a number of major economies could continue to enjoy anunusual degree of stability, granted average luck and currentinstitutions. (JEL E3, E52, F01)     

Voting for Burden Sharing Rules in Public Goods Games

We experimentally investigate whether groups of heterogeneous agents can reach an agreement on how to share the costs of providing a public good. Thereby, we explore the performance of different burden sharing rules being implemented either endogenously or exogenously. In case of an endogenously implemented burden sharing rule, subjects vote for different burden sharing schemes either by unanimity or majority vote. Despite the fact that preferences for the allocation schemes differ among agents, most groups agree upon a common scheme, and consequently avoid an uncoordinated action. Our results reveal both the opportunities and risks of burden sharing negotiations. We find average efficiency levels to increase in case an agreement is reached. If groups however fail to agree upon a common rule, cooperation collapses and efficiency levels decrease compared to a voluntary contribution mechanism being exogenously imposed. Most importantly, agents who face a voting decision on average receive higher payoffs than agents in an exogenously implemented voluntary contribution mechanism and do not earn less than participants in any externally determined burden sharing rule.     

A flexible test of symmetry

Research in consumer behavior, or other surveys, where there is interest in the comparison of response measurement can produce data that is conveniently summarized in an m×m contingency table. In this case, interest may lie in the symmetry of the data in the table or in the homogeneity of the marginal distributions. The purpose of this paper is to examine some of these ideas and propose a test of symmetry which has advantages over the commonly used statistics.     

Endogenizing the provision of money: Costs of commodity and fiat monies in relation to the value of trade

We consider the problem of including the costs and value of the institutions that define money and support trade, within the framework of economic optimization. We compare monetary systems mediated by durable commodity monies, versus pure fiat monies, in order to understand the separation and eventual independence of the institutionally-created value of money from the values of underlying traded goods. We treat the emergence of monetary function as a problem in mechanism design, modeled by minimal strategic market games that overcome a generalized Jevons failure when agents must commit ahead of time to specialist resource production. We consider in particular the problem of defining closures with respect to both money flows and labor-allocation and trading decisions, and show that minimal models require many of the fundamental institutions of banking and contract enforcement found in real economies, in order to define a self-policing system. We define costs, value, and the efficiencies of the institutions that support trade in terms of a natural money-metric welfare function, and compare the characteristics of commodity and fiat monies by these measures. Through careful treatment of the stock/flow distinction in repeated-game settings, we find that commodity money, even when its value derives heavily from its institutional role, remains defined by its flow characteristics, in contrast to fiat money, for which the control function is defined inherently in terms of stock variables. Our notation is somewhat nonconventional for economics but to do justice to econo-physics concepts such as scaling and dimensional analysis and to stress the distinction between stocks and flows, we believe this notation is justified. We provide a full listing of notation in Appendix A.     

Sequential decisions under uncertainty and the maximum theorem

For sequential decision problems in which the decision-maker observes a process of state variables and chooses an adapted process of action variables, the paper defines a topology on the space of measures of processes of state variables which ensures the applicability of Berge's maximum theorem to the decision-maker's optimal behavior. The topology controls for the information available to the decision-maker at each decision date. The paper also discusses the implications of the analysis for the dynamic-programming approach to sequential decision-making under uncertainty, and for equilibrium existence proof strategies in sequential-market models and games.