An urn model to construct an efficient test procedure for response adaptive designs

We study the statistical performance of different tests for comparing the mean effect of two treatments. Given a reference classical test \({\mathcal {T}}_0\), we determine which sample size and proportion allocation guarantee to a test \({\mathcal {T}}\), based on response-adaptive design, to be better than \({\mathcal {T}}_0\), in terms of (a) higher power and (b) fewer subjects assigned to the inferior treatment. The adoption of a response-adaptive design to implement the random allocation procedure is necessary to ensure that both (a) and (b) are satisfied. In particular, we propose to use a Modified Randomly Reinforced Urn design and we show how to perform the model parameters selection for the purpose of this paper. Then, the opportunity of relaxing some assumptions on treatment response distributions is presented. Results of simulation studies on the test performance are reported and a real case study is analyzed.     

Kinship care: Two case management models

Children in the care and custody of the state are increasingly placed with kin rather than in unrelated foster homes. Current estimates suggest that 400,000 children are in kinship care arrangements, with a projected increase to over a half million by 1995 (Center for the Study of Social Policy, 1990). This article provides an overview of the trend toward increasing use of kinship care for foster children and the reasons for this development. It then presents the case management models currently used in kinship care cases by two large public child welfare agencies, and it concludes with discussion of these models and their implications.     

Kinship care: Two case management models

Children in the care and custody of the state are increasingly placed with kin rather than in unrelated foster homes. Current estimates suggest that 400,000 children are in kinship care arrangements, with a projected increase to over a half million by 1995 (Center for the Study of Social Policy, 1990). This article provides an overview of the trend toward increasing use of kinship care for foster children and the reasons for this development. It then presents the case management models currently used in kinship care cases by two large public child welfare agencies, and it concludes with discussion of these models and their implications.     

Gypsy Children and the Italian School System: a closer look

By using the method of participant observation, both in the school and in the community, we were able to gain insight into a series of aspects that characterise the everyday school life of Sinti children in Italian schools. By describing the first school day of four Sinti children I attempt to point out some of the fundamental differences that exist between the children's community environment and the school's institutional environment, differences that lead to discontinuities that the children have to find coping mechanisms for.     

‘Southern‐style’ National Health Services? Recent Reforms and Trends in Spain and Greece

This article analyses recent changes in the Greek and Spanish national health services. The aim is to assess how the period of austerity and further recovery during the 1990s and early 2000s impacted on them in terms of equity and efficiency. This is of interest because of the closeness in time between the universalizing reform laws and the arrival of the conditions for economic convergence established in the Maastricht Treaty. The analysis is also attractive because it deals with the transformation of already mature health insurance systems into national health services, a transformation that is novel in European welfare history. The article addresses the questions of whether austerity has hindered full implementation of the reform laws enacted in the early to mid‐1980s, examining reform trajectories and financing and expenditure trends. Furthermore, it considers the impact on access, understood in terms of population coverage, the array of services provided, waiting lists, and territorial inequalities. Finally, it discusses the introduction of new managerial formulas and attempts at enhancing efficiency. The concluding section states that divergent trajectories have occurred, thus rendering the definition of a ‘Southern model of health care’ difficult. It also provides explanations of the trajectories followed in both national cases and informs on prospects for the future.     

Gender Pay Differentials in Portugal: Contributions to the Employment Policy Debate in the European Union

Since the implementation of the European Employment Strategy in the 1990s, the issue of gender gaps in the European Union labour markets has been granted a high profile. The Portuguese labour market has performed well on various indicators relating to gender equality, namely, participation and employment rates. Nevertheless, a persistent pay gap remains despite the recent evolution of the labour market, especially concerning the average education level of workers. This article investigates the main factors explaining the gender pay gap across two decades and the way those factors perform along time. We also discuss the means of closing the gap in the context of the European Employment Strategy, considering the lessons from other member states. We used wage decomposition techniques to analyse the relative importance of differences in the productive characteristics of workers, differences in the way men and women are distributed among jobs and the relative importance of discrimination practices. Our findings suggest that most of the pay gap is due to discrimination practices. Individual action by economic agents is insufficient to solve the persistent pay gap. Social partners must incorporate this issue within collective bargaining in order to construct an adequate strategy for reducing the gap, which can only be done by engaging men and women, employees and employers.     

Couples’ First Child Intentions and Disagreement: An Analysis of the Italian Case

The aim of this article is to examine the determinants of couples’ childbearing intentions, by explicitly taking into account the agreement or disagreement of the two members of the couple. The relevance of the partner’s reproductive intentions has been well recognised in the literature, but few studies have provided in-depth analyses of the fertility plans of both partners. In our study, we used the household-level data from a survey on “Family and Social Subjects”, carried out by the Italian National Statistical Office in 2003, which provides characteristics on both partners. We adopted a couple’s perspective which allows us to give a unitary picture of the concordant or discordant nature of partners’ first child intentions. We found that a lack of agreement in the reproductive decision-making process is likely to occur in the Italian couples where the role of the woman is less traditional. In particular, cohabitant, highly educated and working women are more likely to be in disagreement with their partners in the decisions concerning having a first child. Being religious may be also a source of discordance in the couples’ reproductive plans. Our findings support the utility of taking a couple-based approach in studies on fertility intentions.     

Structured measurement error in nutritional epidemiology: applications in the Pregnancy, Infection, and Nutrition (PIN) Study

Preterm birth, defined as delivery before 37 completed weeks' gestation, is a leading cause of infant morbidity and mortality. Identifying factors related to preterm delivery is an important goal of public health professionals who wish to identify etiologic pathways to target for prevention. Validation studies are often conducted in nutritional epidemiology in order to study measurement error in instruments that are generally less invasive or less expensive than "gold standard" instruments. Data from such studies are then used in adjusting estimates based on the full study sample. However, measurement error in nutritional epidemiology has recently been shown to be complicated by correlated error structures in the study-wide and validation instruments. Investigators of a study of preterm birth and dietary intake designed a validation study to assess measurement error in a food frequency questionnaire (FFQ) administered during pregnancy and with the secondary goal of assessing whether a single administration of the FFQ could be used to describe intake over the relatively short pregnancy period, in which energy intake typically increases. Here, we describe a likelihood-based method via Markov Chain Monte Carlo to estimate the regression coefficients in a generalized linear model relating preterm birth to covariates, where one of the covariates is measured with error and the multivariate measurement error model has correlated errors among contemporaneous instruments (i.e. FFQs, 24-hour recalls, and/or biomarkers). Because of constraints on the covariance parameters in our likelihood, identifiability for all the variance and covariance parameters is not guaranteed and, therefore, we derive the necessary and suficient conditions to identify the variance and covariance parameters under our measurement error model and assumptions. We investigate the sensitivity of our likelihood-based model to distributional assumptions placed on the true folate intake by employing semi-parametric Bayesian methods through the mixture of Dirichlet process priors framework. We exemplify our methods in a recent prospective cohort study of risk factors for preterm birth. We use long-term folate as our error-prone predictor of interest, the food-frequency questionnaire (FFQ) and 24-hour recall as two biased instruments, and serum folate biomarker as the unbiased instrument. We found that folate intake, as measured by the FFQ, led to a conservative estimate of the estimated odds ratio of preterm birth (0.76) when compared to the odds ratio estimate from our likelihood-based approach, which adjusts for the measurement error (0.63). We found that our parametric model led to similar conclusions to the semi-parametric Bayesian model.