Evolution of harvesting strategies: replicator and resource dynamics

Abstract. Economic theories of managing renewable resources, such as fisheries and forestry, traditionally assume that individual harvesters are perfectly rational and thus able to compute the harvesting strategy that maximizes their discounted profits. The current paper presents an alternative approach based on bounded rationality and evolutionary mechanisms. It is assumed that individual harvesters face a choice between two harvesting strategies. The evolution of the distribution of strategies in the population is modeled through a replicator dynamics equation. The latter captures the idea that strategies yielding above average profits are demanded more than strategies yielding below average profits, so that the first type ends up accounting for a larger part in the population. From a mathematical perspective, the combination of resource and evolutionary processes leads to complex dynamics. The paper presents the existence and stability conditions for each steady-state of the system and analyzes dynamic paths to the equilibrium. In addition, effects of changes in prices are analyzed. A main result of the paper is that under certain conditions both strategies can survive in the long-run. Correspondence to: J. Noailly     

Wage inflation and labour conflicts in the Netherlands : An empirical investigation using the co-integration approach

The ‘wage space’, which is defined as the sum of price inflation and labour productivity growth, has played a major role as an indicator of allowable wage increases in the post-war wage negotiations in the Netherlands. This paper shows that: (a) wages and the wage space are co-integrated; (b) the deviation between wages and the wage space may act as an error correction term in the wage equation when both variables are identified as I(2); and (c) political consensus and the threat of labour conflicts (rather than actual strike activity) may be identified as the ‘mechanism’ behind this error correction in the wage equation.     

Sector-specific capital, “Bang-bang” investment,and the Filippov solution

Bang-bang investment in a two-sector growth model with immobile capital is rational and leads to a unique and globally stable long-run equilibrium along a sliding trajectory. This steady state coincides with the stationary equilibrium in the traditional model with non-sector-specific capital.This article was written while the authors were visiting scholars at Cornell University. We gratefully acknowledge financial assistance from the Erasmus University Trust Fund and the Netherlands Scientific Organization. We would like to thank, without implicating, two anonymous referees, Martijn Herrmann, Jean-Marie Viaene, Claus Weddepohl, and the participants of seminars at the University of Maryland, the University of Montreal, and Erasmus University Rotterdam for perceptive remarks and useful comments. Jeroen Hinloopen and Rien Wagenvoort provided able graphical assistance. The views expressed in this article are those of the authors and not necessarily those of the World Bank.     

A way out of the credibility crisis of models used in integrated environmental assessment

Integrated Assessment Models (IAMs) have been widely used in environmental policy making because they simulate natural and socio-economic systems by integrating knowledge derived from a wide range of disciplines. The current IAMs have been found to be limited due to their inability to display both the value-laden nature of the assumptions that underlie the model and the uncertainties in their outputs. A Post-Normal Science approach is required for dealing with these issues, involving participation of ‘extended peer communities’ providing their ‘extended facts’.     

Earnings management and initial public offerings: Evidence from the Netherlands

This paper presents one of the first studies of earnings management by initial public offering (IPO) firms in a European country. Using a sample of 64 Dutch IPOs, we investigate the pattern of discretionary current accruals (DCA) over time. We find that managers manage their company's earnings in the first year as a public company but not in the years before the IPO. We also examine the impact of earnings management on the long-run stock price performance of IPOs. We find a negative relation between the size of the DCA in the first year as a public company and long-run stock price performance over the next 3 years. A number of additional tests support these findings.     

The Global Determinants of Direct Office Real Estate Returns

We investigate the determinants of direct office real estate returns by analyzing rents, capital appraisals, and total returns. A recently compiled global database of major cities in Asia, Europe, and the United States provides a unique opportunity to give a macro-view on the effects of economic growth and supply and demand factors on nominal real estate returns. The global database provides quarterly observations from 1986 to 1999. To address the smoothness problem of appraisal-based price data and regulated rents, we employ the Generalized Method of Moments to estimate a dynamic panel-data model. The model allows us to combine the cross-sectional and time-series dimension in our quarterly data. We find that gross domestic product, inflation, unemployment, vacancy rate, and the available stock all have an effect on real estate returns.     

Measuring and improving safety culture in organisations: an exploration of tools developed and used in Belgium

To support organisations in addressing their safety culture, practical tools have been developed worldwide. Based on such practical tools, it is possible to measure where an organisation is situated regarding its safety culture in order to identify priority areas, formulate appropriate improvement strategies and determine changes over time. In this paper, it is examined which practical tools to measure and improve safety culture are provided on the Belgian market. In total, 15 Belgian tools were identified, of which 8 agreed to cooperate. Amongst the included tools, there is a lot of variation regarding the methods to diagnose the safety culture and the overall procedure to improve the safety culture. The importance to adapt the tool to the specific needs and context of organisations is acknowledged in most of the tools, as well as the importance to use a multi-method approach to measure the safety culture. Also, it is recognised that all hierarchic levels should participate during the process of diagnosing the safety culture. A point of attention is this overall participation during the validation of the results of the diagnosis, and the priority setting of the recommendations, which is mainly done by the higher management. The development of the Belgian tools is based on experience with a focus on direct practical application, which leads to the fact that none of the tools are validated through scientific evidence. Another point of attention is that organisations pay too little attention at the continuity of safety culture research. And finally, the question can be raised if the safety culture tools actually address the concept ‘safety culture’, or if they address only a subset of the concept. When safety culture is addressed, a comprehensive approach should be used, where technological, organisational, human and external aspects are taken into account as interacting and interrelating elements.     

Supply chain finance schemes in the procurement of agricultural products

Product, information, and finance flows are all interrelated within the modern supply chain; thus, it is now more than ever of paramount importance for practitioners to integrate procurement and financial decisions. This challenge is exemplified in many agricultural supply chains, where operational risks are significant and access to capital differs sharply across firms. We study three management tactics that some large food/beverage manufacturers – situated downstream in these chains – have used to meet the challenge: ordinary fixed price contracts (or soft tolling) with direct suppliers, hard tolling and contract farming where the manufacturer intervenes upstream, providing capital, and coordinating procurement decisions. We place these upstream intervention schemes in the theoretical context of supply chain finance (SCF) and model their application to a three-echelon agricultural supply chain. We perform a numerical study in order to understand how the structure of capital constraints in the chain may influence the manufacturer's choice of SCF scheme. The numerical study is based on a business case that reflects the barley–malt supply chain of Heineken N.V. Despite greater coordination opportunities, we show that upstream intervention is not necessarily preferable for the manufacturer. Nevertheless, the preferred SCF scheme can be inferred on the basis of relatively simple characterization of the capital constraints in the supply chain.