Explaining ethnic violence in black Africa: Independence to 1979

The underlying causes of ethnic mobilisation have been addressed by theories of cultural pluralism, ethnic competition, differential economic incorporation and modernisation. Up to now, no quantitative cross‐national study has tested all these perspectives simultaneously. The results of this study provide support for some aspects of the different theories, with the exception of the theory of differential economic incorporation. The results of the synthetic model stress the importance of examining multiple perspectives in order to avoid only partially correct representations of the historical reasons behind ethnic conflict in black Africa.     

Moral Hazard and Risk Management in Agri‐environmental Policy

This paper develops the key finding of Ozanne, Hogan and Colman (2001) that risk aversion among farmers ameliorates the moral hazard problem in relation to agrienvironmental policy compliance. It is shown that risk averse farmers who face uncertainty in their production income are more likely to comply with such a policy as a means of risk management. In addition, it is shown that a principal who has control over both the level of monitoring and the size of penalty, if detected, can reduce non‐compliance by adjustments to these instruments which increase the variance of farmers' income but leave the expected penalty unchanged. It is concluded that risk management by both principals and agents has the potential to diminish the moral hazard problem, especially given proposed developments in agri‐environmental policy in the European Union.     

Seasonal variability,land values and willingness–to–pay for a forward wheat contract with protein premiums and discounts

This article investigates the impact of a protein premiums and discounts system on the income stream from growing wheat. Based on a biological relationship between protein and yield in uncertain seasonal conditions, it shows that such a system reduces the expected level and variability of wheat income. It is subsequently argued, using a numerical analysis, that protein payments affect both the attraction to wheat growers of forward contracts and the value of land used for wheat. The nature of both of these impacts is related to the level of seasonal variability affecting the land. Consequently, wheat growers in the more unreliable regions of the wheatbelt may have been particularly disadvantaged by the system.     

Sources of Bank Interest Rate Risk

We investigate bank stocks'sensitivity to changes in interest rates and the factors affecting this sensitivity. We focus on whether the exposure of commercial banks to interest rate risk is conditioned on certain balance sheet and income statement ratios. We find a significantly negative relation between bank stock returns and changes in interest rates over the period 1991–1996. We also find that bank characteristics measured from basic financial statement information explain bank stocks'sensitivity to interest rate changes. These results suggest that bank managers, analysts, and regulators can use this information to assess the relative risk exposure of banks.     

A longitudinal study of supply organizational change

This research examines the high level of change in supply organizations of large North American companies using data collected from 51 large North American supply organizations in 1987, 1995 and 2003. Analysis is supplemented by an additional 55 companies for which data were collected in 1995 and 2003. The availability of longitudinal data from individual companies over a 16-year period provided a unique opportunity to trace changes made to each company's supply organizational structure and their roles and responsibilities. Findings suggest that the respondents made major changes in supply organizational structure, supply chain responsibilities, use of purchasing teams, supply involvement in major corporate activities (MCA) and CPO reporting line, title and background.     

Corrigendum to “When is efficiency separable from distribution in the provision of club goods?” [Journal of Economic Theory 90 (2000) 204-221]

This note corrects a slip in Fraser's (J. Econ. Theory 90 (2000) 204-221) treatment of the necessary condition for partial separation of efficiency from distribution in providing a club good. His corrected Theorem 1 shows that many families of utility function can generate partial (and total) separation, thereby considerably extending the scope of his analysis.     

Numerical Maximisation of Likelihood: A Neglected Alternative to EM?

There is by now a long tradition of using the EM algorithm to find maximum‐likelihood estimates (MLEs) when the data are incomplete in any of a wide range of ways, even when the observed‐data likelihood can easily be evaluated and numerical maximisation of that likelihood is available as a conceptually simple route to the MLEs. It is rare in the literature to see numerical maximisation employed if EM is possible. But with excellent general‐purpose numerical optimisers now available free, there is no longer any reason, as a matter of course, to avoid direct numerical maximisation of likelihood. In this tutorial, I present seven examples of models in which numerical maximisation of likelihood appears to have some advantages over the use of EM as a route to MLEs. The mathematical and coding effort is minimal, as there is no need to derive and code the E and M steps, only a likelihood evaluator. In all the examples, the unconstrained optimiser nlm available in R is used, and transformations are used to impose constraints on parameters. I suggest therefore that the following question be asked of proposed new applications of EM: Can the MLEs be found more simply and directly by using a general‐purpose numerical optimiser?     

Mapping historical and contemporary agrarian transformations and capitalist infiltration in a complex upland environment: A case from eastern Nepal

The relationship that mountain communities have with global capitalism are complex, being mediated by a diverse topography and ecology, both of which provide opportunities for capital accumulation, while also isolating older, “pre‐capitalist” modes of production. This paper takes a case study valley from Nepal's eastern hills, tracing over two centuries of agrarian change and evolving interactions between “adivasi” and “semi‐feudal” economic formations with capitalism. In recent years, the expansion of markets, rising demand for cash, and climate stress have solidified migrant labour as a core component of livelihoods, and the primary mechanism of surplus appropriation from the hill peasantry. Through a focus on three altitudinal zones, however, it is demonstrated how the trajectory of this transformation, including the interactions with persisting pre‐capitalist formations, is mediated by both political–economic processes and the local agro‐ecological context.     

Pension plan solvency and extreme market movements: a regime switching approach

We develop and test a new approach to assess defined benefit (DB) pension plan solvency risk in the presence of extreme market movements. Our method captures both the ‘fat-tailed’ nature of asset returns and their correlation with discount rate changes. We show that the standard assumption of constant discount rates leads to dramatic underestimation of future projections of pension plan solvency risk. Failing to incorporate leptokurtosis into asset returns also leads to downward biased estimates of risk, but this is less pronounced than the time-varying discount rate effect. Further modifying the model to capture the correlation between asset returns and the discount rate provides additional improvements in the projection of future pension plan solvency. This reduces the perceived future risk of underfunding because of the negative correlation between interest rate changes and asset returns. These results have important implications for those with responsibility for balancing risk against expected return when seeking to improve the current poor funding positions of DB pension schemes.