Strong Hysteresis due to Age Effects

Strong hysteresis in the labour market (see Cross, 1995) requires workers to be heterogeneous in terms of the cost of hiring and firing. We show how such heterogeneity arises naturally in labour markets due to differences in workers’ age by showing that both the hiring and the firing thresholds for productivity are age dependent. The presence of strong hysteresis does not for this reason depend on ad-hoc differences in the cost of hiring and firing workers.

Hysteresis in the fundamentals of macroeconomics

Two fundamental problems in economic analysis concern the deter mination of aggregate output, and the determination of market prices and quantities. The way economic adjustments are made at the micro level suggests that the history of shocks to the economic environment matters. This paper presents tractable approach for introducing hysteresis into models of how aggregate output and market prices and quantities are determined.

Using Effluent Charges in Promoting Investment in Water Pollution Control Technology: A Model of Coordination Failure among Firms

Untreated wastewater being directly discharged into rivers is a very harmful environmental hazard that needs to be tackled urgently in many countries. In order to safeguard the river ecosystem and reduce water pollution, it is important to have an effluent charge policy that promotes the investment of wastewater treatment technology by domestic firms. This paper considers the strategic interaction between the government and the domestic firms regarding the investment in the wastewater treatment technology and the design of optimal e­ffluent charge policy that should be implemented. In this model, the higher is the proportion of non-investing firms, the higher would be the probability of having to incur an e­ffluent charge and the higher would be that charge. On one hand the government needs to impose a sufficiently strict policy to ensure that firms have strong incentive to invest. On the other hand, it cannot be too strict that it drives out firms which cannot afford to invest in such expensive technology. The paper analyses the factors that affect the probability of investment in this technology. It also explains the difficulty of imposing a strict environment policy in countries that have too many small firms which cannot afford to invest unless subsidised.

The economics of power and control

John Hardman Moore outlines his joint research with Oliver Hart, looking at the economics of power and control and the foundations of contractual incompleteness

Unemployment: natural rate epicycles or hysteresis?

This paper argues that the natural rate of unemployment hypothesis, in which equilibrium unemployment is determined by “structural” variables alone, is wrong: it is both implausible and inconsistent with the evidence. Instead, equilibrium unemployment is haunted by hysteresis. The curious history of the natural rate hypothesis is considered, curious because the authors of the hypothesis thought hysteresis to be relevant. The various methods that have been used to model hysteresis in economic systems are outlined, including the Preisach model with its selective, erasable memory properties. The evidence regarding hysteresis effects on output and unemployment is then reviewed. The implications for macroeconomic policy, and for the macroeconomics profession, are discussed.