Are CO2 Emission Levels Converging Among Industrial Countries?

Time paths of carbon dioxide emissions intwenty-one industrial countries are examinedfrom 1960–1997 to test for stochastic andconditional convergence. Both panel unit roottests and cross-section regressions areperformed. Overall, we find significantevidence that CO₂ emissions haveconverged.     

Purchasing Power Parity

The paper provides a selective and critical review of the literature on purchasing power parity and real exchange rates, with special reference to the literature of the last two decades.     

Two-sided Markets,Competitive Bottlenecks and Exclusive Contracts

We provide a framework for analyzing two-sided markets that allows for different degrees of product differentiation on each side of the market. When platforms are viewed as homogenous by sellers but heterogeneous by buyers, we show that “competitive bottlenecks” arise endogenously. In equilibrium, platforms do not compete directly for sellers, instead choosing to compete indirectly by subsidizing buyers to join. Sellers are left with none of the gains from trade. Despite this, it is sellers who choose to purchase from multiple platforms (multihome). Finally, the role of exclusive contracts to prevent multihoming is explored. We are very grateful to Jose Miguel Abito for research assistance, and to the editor and a referee for helpful comments.     

Evaluating the cost-effectiveness of percutaneous closure of a patent foramen ovale versus medical management in patients with a cryptogenic stroke: from the UK payer perspective

Aims: Percutaneous closure of a patent foramen ovale (PFO) is known to lower the risk of recurrent stroke in patients with a cryptogenic stroke. However, the economic implications of transcatheter PFO closure are less well known. From a UK payer perspective, a detailed economic appraisal of PFO closure was performed for prevention of recurrent ischemic stroke in patients with a PFO who had experienced a cryptogenic stroke.

Materials and methods: A Markov cohort model was constructed using a 5-year time-horizon with a patient mean age of 45.2 years, reflecting the characteristics reported in the REDUCE trial. Transition probabilities, clinical inputs, costs, and utility values were ascertained from published and national costing sources. Total costs, incremental costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios were calculated, utilizing a discount rate of 3.5%. A range of univariate and probabilistic sensitivity analyses were also performed.

Results: When applying a willingness-to-pay (WTP) threshold of £20,000/QALY in accordance with NICE guidelines, PFO closure compared with antiplatelet therapy alone showed a beneficial cost/QALY of £18,584, attained at 4 years. Applying discount rates of 0% and 6% had a negligible effect on the base-case model findings. PFO closure demonstrated a 76.9% probability of being cost-effective at a WTP threshold of £20,000/QALY at a 5-year time-horizon.

Limitations: This model focused specifically on UK stroke patients and typically enrolled young (mean age <65 years old) patients. Hence, caution should be taken when comparing data vs non-UK populations, and it remains unclear how older patients might have affected cost-effectiveness findings, as the risk of paradoxical embolism can persist as patients age.

Conclusion: Percutaneous closure of a PFO is cost-effective compared with antiplatelet therapy alone, underlining the economic benefits potentially afforded by this treatment in selected patients.     

Children’s health benefits of reducing environmental tobacco smoke exposure: evidence from parents who smoke

This paper uses data from the 1991 National Maternal and Infant Health Survey to estimate propositions derived from a model of intrahousehold allocation, wherein parents engage in a consumption activity (smoking) that produces own utility, while generating environmental tobacco smoke (ETS) that harms their children’s health. We find a statistically significant negative association between sample mothers‘ assessed health of their children and the children’s daily exposures to ETS. Mothers’ average annual willingness-to-pay (WTP) for a 1-hour-per-day reduction in child ETS exposure (about a 17% decrease in daily exposure) is about $150. WTP estimates for respondent mother and child health status further suggest that smoking mothers on average value their child’s health roughly 55% higher than their own health. Helpful comments and suggestions by Scott Atkinson, Donald Kenkel, and two anonymous referees are gratefully acknowledged. Marcy Agee and Stefanos Nastis provided valuable research assistance. Although the U.S. Environmental Protection Agency provided financial support through Grant#R82871601, the research has not been subjected to the Agency’s required peer and policy review and therefore does not necessarily reflect the views of the Agency     

Recursive utility and the rate of impatience

Summary This paper studies the role of impatience in a model with recursively defined preferences. A method is introduced whereby the rate of impatience can be parametrically adjusted for a given aggregator. Using lattice programming and Topkis' Theorem (1978) sufficient conditions are discovered to guarantee that a reduction in the rate of impatience will lead to greater capital stocks in every period.I would like to thank my advisor John H. Boyd III for his encouragement at several steps along the way. I would also like to thank P. Dutta, Raghu Sundaram and William Thompson for several helpful suggestions. Finally, I have benefited tremendously from the advice of an anonymous referee. This article reflects the views of the author and does not necessarily reflect the views of the Federal Trade Commission or any individual Commissioner.     

On ‘Informationally Robust Equilibria’ for Bimatrix Games

Informationally robust equilibria (IRE) are introduced in Robson (Games Econ Behav 7: 233–245, 1994) as a refinement of Nash equilibria for strategic games. Such equilibria are limits of a sequence of (subgame perfect) Nash equilibria in perturbed games where with small probability information about the strategic behavior is revealed to other players (information leakage). Focusing on bimatrix games, we consider a type of informationally robust equilibria and derive a number of properties they form a non-empty and closed subset of the Nash equilibria. Moreover, IRE is a strict concept in the sense that the IRE are independent of the exact sequence of probabilities with which information is leaked. The set of IRE, like the set of Nash equilibria, is the finite union of polytopes. In potential games, there is an IRE in pure strategies. In zero-sum games, the set of IRE has a product structure and its elements can be computed efficiently by using linear programming. We also discuss extensions to games with infinite strategy spaces and more than two players. The authors would like to thank Marieke Quant for her helpful comments.     

Inflation and growth: Explaining a negative effect

The paper presents a monetary model of endogenous growth and specifies an econometric model consistent with it. The economic model suggests a negative inflation-growth effect, and one that is stronger at lower levels of inflation. Empirical evaluation of the model is based on a large panel of OECD and APEC member countries over the years 1961–1997. The hypothesized negative inflation effect is found comprehensively for the OECD countries to be significant and, as in the theory, to increase marginally as the inflation rate falls. For APEC countries, the results from using instrumental variables also show significant evidence of a similar behavior. The nature of the inflation-growth profile and differences in this between the regions are interpreted with the credit production technology of the model in a way not possible with a standard cash-only economy. Research assistance by László Konya, Rezida Zakirova, and Anton Nakov and comments by Michal Kejak, Myles Wallace and Toni Braun are kindly acknowledged, along with comments from the 17^th European Economic Association Meetings, Venice, and the 10^th International Panel Data Conference, Berlin. We also thank the editors and referees for valuable comments, and the first author is grateful to Central European University for research funds.