Survival Trees: An Alternative Non-Parametric Multivariate Technique for Life History Analysis

In this paper an extension of tree-structured methodology to cover censored survival analysis is discussed. Tree-based methods (also called recursive partitioning) provide a useful alternative to the classical survival data analysis techniques, such as the semi-parametric model of Cox, whenever the main purpose is defining groups of individuals, either with complete or censored life history, having different survival probability, based on the values of selected covariates. The essential feature of recursive partitioning is the construction of a decision rule in the form of a binary tree. Trees generally require fewer assumptions than classical methods and handle non standard and non linear data structures efficiently. Tree-growing methods make the processes of covariate selection and grouping of categories in event history models explicit. An example concerning the analysis of time to marriage of Italian women is presented.     

A new 'biased coin design' for the sequential allocation of two treatments

Summary.  Efron's biased coin design is a well-known randomization technique that helps to neutralize selection bias in sequential clinical trials for comparing treatments, while keeping the experiment fairly balanced. Extensions of the biased coin design have been proposed by several researchers who have focused mainly on the large sample properties of their designs. We modify Efron's procedure by introducing an adjustable biased coin design, which is more flexible than his. We compare it with other existing coin designs; in terms of balance and lack of predictability, its performance for small samples appears in many cases to be an improvement with respect to the other sequential randomized allocation procedures.     

A sociological economy of HIV/AIDS vaccine partnerships: case studies from Africa and India

Public–private partnerships (PPPs) are perhaps the key emergent theme in the delivery of what the socio-economic literature terms global public goods. In light of the problems relating to the distribution of health services and products in developing countries, partnerships between public and private institutions are often proposed as an innovative mechanism to reconnect and reorient supply and demand. In this area, the International Aids Vaccine Initiative (IAVI), which is driving the development of candidate HIV/AIDS vaccines through injections of capital into the research process, represents a significant case study. IAVI seeks to form partnerships between key public and private interests committing them to sharing the risks, costs and benefits of research into an effective and affordable vaccine against HIV. Our empirical work covers partnerships based in several countries including Kenya, Uganda, Rwanda and India. Our early findings highlight IAVI's ability as a learning institution as it adapts its institutional arrangements to various local contexts. An offshoot of this appears to be the building of real local capacity.     

A theoretical analysis of the power of biased coin designs

Outlining some recently obtained results of Hu and Rosenberger [2003. Optimality, variability, power: evaluating response-adaptive randomization procedures for treatment comparisons. J. Amer. Statist. Assoc. 98, 671–678] and Chen [2006. The power of Efron's biased coin design. J. Statist. Plann. Inference 136, 1824–1835] on the relationship between sequential randomized designs and the power of the usual statistical procedures for testing the equivalence of two competing treatments, the aim of this paper is to provide theoretical proofs of the numerical results of Chen [2006. The power of Efron's biased coin design. J. Statist. Plann. Inference 136, 1824–1835]. Furthermore, we prove that the Adjustable Biased Coin Design [Baldi Antognini A., Giovagnoli, A., 2004. A new “biased coin design” for the sequential allocation of two treatments. J. Roy. Statist. Soc. Ser. C 53, 651–664] is uniformly more powerful than the other “coin” designs proposed in the literature for any sample size.     

“Good” corporate governance and the quality of internal auditing departments in Italian listed firms. An exploratory investigation in Italian listed firms

One of the most important issue relating to corporate governance reports refers to their ability to provide users with a complete set of information regarding the effective ability of an entity to achieve oversight objectives by the compliance to corporate governance practices required by a specific law or industry code. In addition, other features, such as the quality of the internal auditing function or the sensitivity of top management to issues relating to corporate internal controls and risk management, can also be taken into account when formulating a judgment on the quality of corporate governance practices. Is there an association between the compliance to codes and internal controls effectiveness? We propose to assess the quality of corporate governance through a proxy that considers several characteristics of internal audit departments and combines them to determine an Internal Audit Departments global quality index—IAD Index. To define IAD global quality we consider the effectiveness of an internal audit function analysing its operational aspects. The IAD Index is based on several signalling elements that previous literature assumed as proxies for quality of IADs which are grouped into four pillars: a formal quality index; a static quality index; an activity-related quality index; and a performance-linked quality index. We then test the IAD index on a sample of Italian listed firms and conclude that there are significant associations (positive and negative) between the degree of compliance to some corporate governance regulations for listed firms and the IAD Index for the sample being considered.     

Recursive Equilibrium in Stochastic Overlapping‐Generations Economies

We prove the generic existence of a recursive equilibrium for overlapping‐generations economies with uncertainty. “Generic” here means in a residual set of utilities and endowments. The result holds provided there is a sufficient number of potentially different individuals within each cohort.     

Statistical Certification of Software Systems

Common software release procedures based on statistical techniques try to optimize the trade-off between further testing costs and costs due to remaining errors. We propose new software release procedures where the aim is to certify with a certain confidence level that the software does not contain errors. The underlying model is a discrete time model similar to the geometric Moranda model. The decisions are based on a mix of classical and Bayesian approaches to sequential testing and do not require any assumption on the initial number of errors.     

Contested Terrain of the Global Fisheries: “Dolphin-Safe” Tuna,The Panama Declaration,and the Marine Stewardship Council1

ABSTRACT The globalization of socio-economic relations is a central topic of discussion in both the general literature on economy and society and in the area of food and agriculture. Many maintain that we are in a transition from one era, termed Fordism, to another, called Global Post-Fordism. We use the case of two fisheries eco-labeling programs to inform discussions regarding the emergence of stabilizing socio-economic mechanisms in the Global Post-Fordist era. We argue that recent developments in the tuna-dolphin case, the first major experiment with eco-labeling in the fisheries industries, combined with the Marine Stewardship Council, an initiative designed to regulate and certify a system of global “sustainable fisheries” through an eco-labeling program, provide valuable insights into the ideological and organizational structure of salient global actors in the Post-Fordist era. The discussion addresses (1) the contested terrain within the “North” and between the “North” and the “South” regarding eco-legislation to regulate the global fisheries; (2) the fracturing of the environmental movement into “mainstream” and “grassroots” camps and the resulting inability to maintain a coordinated agenda to counter the globalization project; and (3) the emergence of new forms of supranational state-like regulatory mechanisms that combine science with free trade and environmental ideals and propose to resolve the global fisheries crises by providing sustainable socio-economic coordination. We conclude that the emergence of these supra-national state-like NGOs raises important implications for the sovereignty of nation-states and democratic action on the part of subordinate groups opposed to the globalization project.     

Human mobility in the context of environmental and climate change: Recent data collection tools from the International Organization for Migration to address key methodological and conceptual issues

This paper outlines recent data collection tools and methodologies that the International Organization for Migration (IOM) has been using in order to gather information on human mobility as influenced by environmental factors and their impacts. It looks at alternative ways for collecting and analysing data in the face of methodological challenges related to the multicausality of movements, the voluntary/involuntary continuum in human (im)mobility decisions in the context of environmental and climate change, and the policy and epistemological imperative from viewing migration as an adaptation strategy. The paper finds that certain data collection approaches can be quickly deployed in rapid-onset disasters as well as applied in contexts of gradual, slow-onset environmental change to provide information useful for operational responses to immediate crises and/or for developing policies in response. Some of the tools can be useful in both contexts and may support both immediate and long-term operational, policy and research objectives.