Optimal prediction pools

We consider the properties of weighted linear combinations of prediction models, or linear pools, evaluated using the log predictive scoring rule. Although exactly one model has limiting posterior probability, an optimal linear combination typically includes several models with positive weights. We derive several interesting results: for example, a model with positive weight in a pool may have zero weight if some other models are deleted from that pool. The results are illustrated using S&P 500 returns with six prediction models. In this example models that are clearly inferior by the usual scoring criteria have positive weights in optimal linear pools.     

Household Debt and Financial Constraints in Australia

Over the past decade, household debt (as a share of household income) has reached historically high levels. This has raised concerns about whether, as a result of the rise in debt, households are now more financially ‘fragile'. Using household survey data, a logit model is constructed to examine the relationship between the probability of being financially constrained and the economic and demographic characteristics of households in Australia. We find that the probability of a household being constrained is significantly affected by demographic and economic variables such as age, home ownership, weekly household income, and the share of income going to repayments on mortgage debt. Comparing survey results across time, it appears that the overall proportion of households that are financially constrained has fallen or, at worst, remained unchanged between 1994 and 2001. Much of the rise in debt appears to have been due to unconstrained households taking on more debt. As such, the rise in the aggregate debt to income ratio associated with owner‐occupier mortgages appears to be the result of voluntary household choice and not to be associated with an increase in household financial distress.     

From core to periphery and back: A study on the deliberate shaping of knowledge flows in interfirm dyads and networks

We study 892 Italian motorcycle industry projects carried out via 184 different buyer–supplier and supplier‐supplier relationships to provide evidence on the knowledge dynamics occurring in dyads and networks and to understand the underexplored but important (perhaps even dominant) leading role that some firms play in the evolution of networks and interfirm learning processes. We develop a multiphase model which, from a multilevel perspective addressing different relational subsets, suggests how firms can best organize to generate and exchange knowledge efficiently. We argue that extant theoretical perspectives can profitably draw on our findings to strengthen their dynamic components and help them explain the widely diffused ‘exploring through partner’ strategies more effectively. Copyright © 2013 John Wiley & Sons, Ltd.     

Diversification by entry into a new submarket?

Using a dataset on the subsector and geographical segmentation of 208 Pharmaceutical companies, a Bayesian panel probit is used to analyze the role of state dependency, size and achieved diversification in affecting entry decision. We properly account for unobservable heterogeneity in a context with nonstrictly exogenous regressors. We find that achieved diversification, measured by the number of submarkets already entered affects negatively the probability of entry. Beside some country-specific exceptions, size and the lagged dependent variable do not seem to be relevant.     

A numerical representation of semiorders on a countable set

Let be a semiorder on a countable setX and letx⁰ y if and only if either there existsx withxxy or there existsx withxxy. Then ⁰ is a preference relation with transitive indifference, which can be represented by a utility functionf of the usual sort. It is well known that is represented by a pair of real-valued functionsu, v, in the sense thatxy if and only ifu(x)>v(y). We prove that there exists a pair of functionsu, v, representing , such thatu+v is the utility function which represents in the usual sense. Moreover it is easily seen that, for such a pair of functionsu, v, we havex⁰ y if and only if eitheru(x)>u(y) or (u(x)=u(y) andv(x)>v(y)).

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Sommario Consideriamo unsemiordine su un insiemeX numerabile e poniamox⁰ y se e solo se esistex tale chexxy, oppure esistex tale chexxy. In questo caso ⁰ è unordine debole, che può essere rappresentato da una funzione di utilitàf nel senso usuale. D'altra parte è rappresentato da una coppia di funzioniu, v, nel senso chexy se e solo seu(x)>v(y). In questo lavoro si prova che ammette una rappresentazioneu, v tale chex⁰ y se e solo seu(x)+v(x)>u(y)+v(y). Si dimostra altresì che, con riguardo ad una siffatta rappresentazioneu, v di , riescex⁰ y se e solo seu(x)>u(y) oppure (u(x)=u(y) ed anchev(x)>v(y)).

     

The Design of Optimal Education Policies

This paper studies the education policy chosen by a utilitarian government. In the model, households differ in their income and in their children&'s ability; income is observed by the government, but ability is private information. Households can use private education, but cannot borrow to finance it. The government can finance education with income tax, but at the cost of blunting the individuals' incentive to exert labour market effort. The optimal education policy we derive is elitist: it increases the spread between the educational achievement of the bright and the less bright individuals, compared to private provision. It is also such that the education received by less bright individuals depends positively on their parental income. Finally, the optimal education policy is input regressive, in the sense of Arrow (1971, Quarterly Journal of Economics, 38, 175–208): households with higher income and brighter children contribute less in tuition fees towards the cost of the education system than households with lower income and less bright children.     

European integration and the pay policies of British multinationals

European economic integration has generated intense interest in the prospect of a European labour market. This article brings new evidence to bear on the issue of employer responses to European integration and concludes that British owned multinational companies have, as yet, only made partial moves towards the Europeanisation of their pay determination arrangements.     

Revenue Sharing Rules for International Telephony

The method for settling telecommunications payments between operators in different countries is the reciprocal accounting rate system. This is a discriminatory system, because different operators pay different prices to access the same national network and these price differences are not related to different costs of providing the service.Reforms of the accounting rate system are currently under discussion in international organizations. In this paper we study the effects of the existing regime and of the main alternative proposal, the international traffic terminating fee, on the retail price of international telephone calls.Our main result is that the current regime of reciprocal accounting rates may determine lower prices than the proposed alternative system.