Global instability in experimental general equilibrium: the Scarf example

Scarf (Int. Econ. Rev. 1 (1960) 157) proposed a model of dynamic adjustment in which the standard tatonnement price adjustment process orbits around, rather than converges to, the competitive equilibrium. Hirota (Int. Econ. Rev. 22 (1981) 461) characterized the price paths. We explore the predictions of Scarf's model in a non-tatonnement experimental double auction. The average transaction prices in each period do follow the path predicted by the Scarf and Hirota models. When the model predicts convergence the data converge; when the model predicts orbits, the data orbit in the direction predicted by the model. Moreover, we observe a weak tendency for prices within a period to follow the path predicted by the model.     

Average Monotonic Cooperative Games

A subclass of monotonic transferable utility (T.U.) games is studied: average monotonic games. These games are totally balanced. We prove that the core coincides with both the bargaining set à la Davis and Maschler and the bargaining set à la Mas-Colell. To obtain this result a technique based on reduced games is used. Journal of Economic Literature Classification Number: C71     

Finding Pareto Optimal Insurance Contracts

This paper deals with on-line computation—or step-wise learning—of Pareto optimal insurance contracts. Our approach tolerates that the loss distribution might be unknown, intractable, or not well specified. Thus we accommodate fairly inexperienced parties. Losses are here simulated or observed, one at a time, and they cause iterated revisions of the premium. The mechanical and global nature of probability calculus thereby yields to more tentative, myopic procedures, possibly closer to how humans operate or reason in face of risk. Sequential revisions may also reduce the expense of insurers' time and money in seeking sufficient statistics. Emphasized below is the remarkable simplicity and stability of the resulting adaptive procedures. Special attention goes to catastrophic risks, and to subsidized or competitive insurance.     

Another view on optimal design for estimating the point of extremum in quadratic regression

In this paper we illustrate how certain design problems can be simplified by reparametrization of the response function. This alternative viewpoint provides further insights than the more traditional approaches, like minimax, Bayesian or sequential techniques. It will also improve a practitioner’s understanding of more general situations and their “classical” treatment.     

Nonlinear Aspects of Goods-Market Arbitrage and Adjustment: Heckscher''s Commodity Points Revisited

We propose that analysis of purchasing power parity (PPP) and the law of one price should explicitly take into account the possibility of “commodity points”—thresholds delineating a region of no central tendency among relative prices, possibly due to lack of perfect arbitrage in the presence of transaction costs and uncertainty. More than 80 years ago, Heckscher stressed the importance of such incomplete arbitrage in the empirical application of PPP. We devise an econometric method to identify commodity points. Price adjustment is treated as a nonlinear process, and a threshold autoregression offers a parsimonious specification within which both thresholds and adjustment speeds are estimated by maximum likelihood methods. Our model performs well using post-1980 data, and yields parameter estimates that appear quite reasonable: adjustment outside the thresholds might imply half-lives of price deviations measured in months rather than years, and the thresholds correspond to popular rough estimates as to the order of magnitude of actual transport costs. The estimated commodity points appear to be positively related to objective measures of market segmentation, notably nominal exchange rate volatility.J. Japan Int. Econ.December 1997,11(4), pp. 441–479. Department of Economics, University of California, Berkeley, California 94720-3880; and Department of Economics, Northwestern University, Evanston, Illinois 60208-2600.     

Money growth volatility and the demand for money in Germany: Friedman’s volatility hypothesis revisited

Money Growth Volatility and the Demand for Money in Germany: Friedman’s Volatility Hypothesis Revisited. — Recently, the Bundesbank claimed that monetary targeting has become considerably more difficult by the increased volatility of short-term money growth. The present paper investigates the impact of German money growth volatility on income velocity and money demand in view of Friedman’s money growth volatility hypothesis. Granger-causality tests provide some evidence for a velocity/volatility linkage. However, the estimation of volatility-augmented money demand functions reveals that — in contrast to Friedman’s hypothesis — increased money growth volatility lowered the demand for money.     

OPTIONS AND EFFICIENCY IN MULTIDATE SECURITY MARKETS

This paper extends the work of Ross (1976; Q. J. Econ. (90)1, 75–89) to multidate security markets. First, we show that if a primitive security separates states at the terminal date, then there exist multiperiod European options on that security generating dynamically complete markets. Second, we show that if a primitive security conditionally separates states at the terminal date, then there exist multiperiod European options on that security generating generically dynamically complete markets provided that certain conditions hold. Third, we show that there are economies for which the minimum number of multiperiod European options on a primitive security generating generically dynamically complete markets is relatively large. Finally, we show that in these economies, a relatively small number of multiperiod European options on possibly different portfolio strategies of primitive securities generates generically dynamically complete markets.     

Global economy gathering strength

Encouraged by a highly expansionary economic policy, the global economy is enjoying a rapid upturn. Utilisation of capacity is high in many sectors, particularly in the growth centres of the USA and East Asia, where China leads the field. With inflationary risks on the increase, most countries are now shifting the focus of economic policy. Fiscal policy in particular can be expected to provide little in the way of further stimulus. In addition, there has been a turnaround in interest rates in many countries. Yet how quickly can the monetary reins be tightened without jeopardising growth or endangering price stability?