Some results on optimality in models with heteroscedastic errors from partial optimum designs

This paper studies optimum designs for linear models when the errors are heteroscedastic. Sufficient conditions are given in order to obtainD-, A- andE-optimum designs for a complete regression model from partial optimum designs for some sub-parameters. A result about optimality for a complete model from the optimality for the submodels is included. Supported by Junta de Andalucía, research group FQM244.     

Structural reform of social security pensions in Latin America: Models, characteristics, results and conclusions

The structural reform of social security pensions is the subject of international debate, and Latin America has been a pioneer of such reform. The region has gathered experience over two decades, and had an important influence on other regions. This article gathers legal and statistical data about reform in ten countries of Latin America, in order (1) to analyse the three distinct general models followed and note the characteristics of the reforms in the different countries; (2) to evaluate the performance of the reforms against nine conventional assumptions about its effects; (3) to draw useful lessons from these reforms for the region and other countries.     

Estimating Cuban gross domestic product per capita in dollars using physical indicators

A methodology for estimating levels of gross domestic product per capita (GDP/capita) which obviates the need for estimating GDP/capita in domestic currency and converting to another currency is the physical indicators (PI) approach developed by Janossy-Ehrlich. Using this methodology, estimates of Cuban GDP/capita in dollars for four years (1965, 1970, 1975 and 1977) have been made. The estimates rely on the relationships between GDP/capita in dollars and levels of consumption or production of 24 physical indicators in 28 reference countries for each of the four years. The relationships are estimated using both univariate and multivariate regression techniques. The PI estimates of GDP/capita in dollars are compared with other measures of Cuban macroeconomic performance to test their reasonableness. The paper closes with some tentative conclusions regarding the applicability of the PI method to the estimation of GDP/capita in dollars for Cuba and for other developing countries.     

JACKKNIFE TESTS FOR HETEROSCEDASTICITY IN THE GENERAL LINEAR MODEL

In this paper, tests based on the Jackknife technique are proposed to test for heteroscedasticity in the linear regression model when the errors are non-normal. These are the Jackknifed Goldfeld-Quandt (GQ), and jack-knife related variations of White (H), Lagrange multiplier (LM), Glejser (GL) and Bickel (B) tests. The power of the proposed tests is compared with that of GQ, H, LM, GL and B tests; and the robustness to the error distribution is analyzed under several heteroscedastic assumptions. The GQ test is by far the best test if the error distribution is close to normal, however, GQ test is not robust against non-normal errors. By applying the jackknife technique to the regression a more robust statistic (GQJRG) is produced but the cost is a loss in power. The GQJRG statistic generally is not M powerful as the Bickel (BlOLS) and Glejser (GLlOLS) statistics.     

A-optimal designs for heteroscedastic multifactor regression models

Abstract

This paper searches for A-optimal designs for Kronecker product and additive regression models when the errors are heteroscedastic. Sufficient conditions are given so that A-optimal designs for the multifactor models can be built from A-optimal designs for their sub-models with a single factor. The results of an efficiency study carried out to check the adequacy of the products of optimal designs for uni-factor marginal models when these are used to estimate different multi-factor models are also reported.     

On the manipulation of social choice correspondences

Duggan and Schwartz (Soc Choice and Welfare 17: 85–93, 2000) have proposed a generalization of the Gibbard–Satterthwaite Theorem to multivalued social choice rules. They show that only dictatorial rules are strategy-proof and satisfy citizens sovereignty and residual resoluteness. Citizens sovereignty requires that each alternative is chosen at some preference profile. Residual resoluteness compels the election to be single-valued when the preferences of the voters are “similar”. We propose an alternative proof to the Duggan and Schwartz’s Theorem. Our proof highlights the crucial role of residual resoluteness. In addition, we prove that every strategy-proof and onto social choice correspondence concentrates the social decision power in the hands of an arbitrary group of voters. Finally, we show that this result still holds in a more general framework in which voters report their preferences over sets of alternatives.     

On strategy-proof social choice correspondences: a comment

In a recent paper, Sato (Soc Choice Welf doi:) has provided two alternative definitions of strategy-proofness for social choice correspondences and proved that they are incompatible with the joint requirements of anonymity, neutrality, and a minimal range condition. In this note, we use the results in Rodríguez-álvarez (Soc Choice Welf 29:175–199, 2007) to directly prove stronger versions of Sato’s theorems. The author wishes to thank Shin Sato and John Weymark for their comments and suggestions. Financial support from the Ministerio de Educación y Ciencia through the Programa Ramón y Cajal 2006 and grant SEJ-2005-04805, the Consejería de Innovación, Ciencia y Empresa, Junta de Andalucía through grant SEJ-01645, and the Fundación Ramón Areces is gratefully acknowledged.     

La protection sociale au Chili: des réformes pour plus de justice

Au début des années quatre‐vingt, le Chili – imité ensuite par d'autres pays – a lancé une réforme privatisant en partie ou totalement les systèmes de l'assurance maladie et des retraites. Mise en ?uvre sans concertation sociale, la réforme se fera aux dépens des principes de solidarité et de justice sociale, contribuant à la progression de la pauvreté et des inégalités. Depuis, les gouvernements démocratiques ont apporté bien des corrections. L'auteur analyse les progrès réalisés, mais aussi les inégalités qui persistent – vues sous l'angle de la couverture, du sexe et de la contribution financière – et les problèmes qui restent à résoudre.     

The performance of social security contributory and tax‐financed pensions in Central America,and the effects of the global crisis

Over the last 30 years, Latin America has pioneered structural pension reforms. This article focuses on a representative regional sample of seven Central American countries with diverse levels of development (Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua and Panama) studying contributory and tax‐financed pensions as well as recent pension reforms. It comparatively assesses system performance regarding five social security principles: unity; universal coverage; adequacy of benefits; equal treatment, solidarity and gender equality; and financial sustainability. It also evaluates the impact of the world crisis on these pension systems, highlighting the differences between public and private pensions, and extracts lessons and suggests policies for the future.