Smoothed empirical likelihood confidence intervals for the relative distribution with left‐truncated and right‐censored data

The study of differences among groups is an interesting statistical topic in many applied fields. It is very common in this context to have data that are subject to mechanisms of loss of information, such as censoring and truncation. In the setting of a two‐sample problem with data subject to left truncation and right censoring, we develop an empirical likelihood method to do inference for the relative distribution. We obtain a nonparametric generalization of Wilks' theorem and construct nonparametric pointwise confidence intervals for the relative distribution. Finally, we analyse the coverage probability and length of these confidence intervals through a simulation study and illustrate their use with a real data set on gastric cancer. The Canadian Journal of Statistics 38: 453–473; 2010 © 2010 Statistical Society of Canada     

呆坏账核算的修订及其对我国核算影响的研究——1993年SNA修订问题研究系列之七

一、问题的提出1997年亚洲金融危机后,许多国家的银行和政府出现了大量的呆坏账,因此,泰国当局向国际国民核算工作组(ISWGNA)提出如何处理呆坏账的问题,希望工作组就应付利息计算给予解释,并确定一个标准和方法来冲销呆坏账,此方法应与其他主要宏观经济统计体系(国际收支、政府财政、货币与银行统计)保持一致。从我国的实际情况看,我国商业银行特别是四大国有商业银行中也存在大量的呆坏账,2005年全部商业银行不良贷款余额为1·3万亿元,不良贷款率为8·6%,其中很多不良贷款变为呆坏账(见表1)。所以,我国也面临着同样的呆坏账核算问题,研…     

Fisher's Information for Discretely Sampled Lévy Processes

This paper studies the asymptotic behavior of Fisher's information for a Lévy process discretely sampled at an increasing frequency. As a result, we derive the optimal rates of convergence of efficient estimators of the different parameters of the process and show that the rates are often nonstandard and differ across parameters. We also show that it is possible to distinguish the continuous part of the process from its jumps part, and even different types of jumps from one another.     

A Risk-Benefit Analysis of French High Fish Consumption: A QALY Approach

The health risk and the nutritional benefit of a food are usually assessed separately. Toxicologists recommend limiting the consumption of certain fish because of methylmercury; while nutritionists recommend eating more oily fish because of omega 3. A common evaluation is imperative to provide coherent recommendations. In order to evaluate the risks along with the benefits related to fish consumption, a common metric based on the quality-adjusted life year (QALY) method has been used. The impact of a theoretical change from a medium n-3 PUFAs intake to a high intake is studied, in terms of the cardiovascular system (CHD mortality, stroke mortality and morbidity) and on fetal neuronal development (IQ loss or gain). This application can be considered as a sensitive analysis of the model used and looks at the impact of changing the dose-response relationships between cardiovascular diseases and n-3 PUFAs intakes. Results show that increasing fish consumption may have a beneficial impact on health. However, the confidence interval of the overall estimation has a negative lower bound, which means that this increase in fish consumption may have a negative impact due to MeHg contamination. Some limits of the QALY approach are identified. The first concerns determination of the dose-response relationships. The second concerns the economic origins of the approach and of individual preferences. Finally, since only one beneficial aspect and one risk element were studied, consideration should be given to how other beneficial and risk components may be integrated in the model.     

The Dynamics of Research Alliances: Examining the Effect of Alliance Experience and Partner Characteristics on the Speed of Alliance Entry in the Biotech Industry

Few studies have moved beyond the dyadic level of an ongoing alliance and examined factors contributing to the success of entering a series of alliances. In this paper we expect biotechnology firms over time to learn from their alliance experience and to develop general alliance capabilities. Specifically, we expect the speed with which they enter into new research alliances, e.g. their alliance formation rate, to be affected by capabilities built up in prior alliances as well as by characteristics of their partners. We use longitudinal event history data for the complete population of US biotechnology firms for 1973–1999 to test four hypotheses about factors affecting the rate of new alliance formation. Our analysis suggests that the speed of entering research alliances is affected by prior experience of the focal firm, but not by partner characteristics. Our findings provide evidence that biotech firms learn how to learn more effectively from multiple research alliances; however, this effect is generalized and not tied to specific characteristics of the alliance partner.     

Drivers and Enablers That Foster Environmental Management Capabilities in Small‐ and Medium‐Sized Suppliers in Supply Chains

The limited capabilities and resources available within many small‐ and medium‐sized enterprises frequently hamper an effective response to environmental pressures, which in turn hurts large buying firms (i.e., customers). Using a case study method with multiple suppliers of two large buying firms, we mapped factors that initiated and improved environmental capabilities in small‐ and medium‐sized enterprises over time. Through several specific mechanisms, buyers' green supply chain management initiated and then enabled the improvement of suppliers' environmental capabilities. Independent of buyers, internal championing of environmental concerns also provided an impetus for small‐ and medium‐sized enterprise suppliers to acquire resources outside the supply chain. Thus, synergistic linkages emerged in supportive buyer‐supplier relationships, resource acquisition, and capability development. When these findings are combined with earlier research on larger suppliers, an integrative framework emerges that provides direction for suppliers, buyers, and public agencies seeking to improve environmental performance.     

Value of Sharing Production Yield Information in a Serial Supply Chain

New developments in corporate information technology such as enterprise resource planning systems have significantly increased the flow of information among members of supply chains. However, the benefits of sharing information can vary depending on the supply chain structure and its operational characteristics. Most of the existing research has studied the impact of sharing downstream information (e.g., a manufacturer sharing information with its suppliers). We evaluate the benefits of sharing upstream yield information (e.g., a supplier sharing information with the manufacturer) in a two‐stage serial supply chain in which the supplier has multiple internal processes and is faced with uncertain output due to yield losses. We are interested in determining when the sharing of the supplier's information is most beneficial to the manufacturer. After proposing an order‐up‐to type heuristic policy, we perform a detailed computational study and observe that this information is most beneficial when the supplier's yield variance is high and when end‐customer demand variance is low. We also find that the manufacturer's backorder‐to‐holding cost ratio has little, if any, impact on the usefulness of information.     

Root and Branch Restructuring to Achieve Major Cuts: The Social Policy Programme of the 2010 UK Coalition Government

The 2010 Coalition has set itself the challenge of combining an unprecedentedly rapid and profound retrenchment with a fundamental restructuring of the public sector, both to be accomplished within five years. The immediate justification is a presumed need to reduce national indebtedness. The longer‐term goal is to shrink the state, free up the market and set British political economy on a new course. The programme has encountered a number of set‐backs and some elements appear more likely to be realized than others. This article considers the objectives of the Coalition programme and the likely outcomes, using evidence from a number of sources including comparisons with the experience of retrenchment elsewhere and analysis of previous rounds of public spending cut‐backs.     

Therapeutic residential care in Spain. Population treated and therapeutic coverage

Therapeutic residential care (TRC) is the name given to specialized children's homes for treating cases with severe emotional and behavioural problems that have been placed in residential care. A recent international review has revealed great diversity in the referral criteria of cases and in the models of intervention carried out. The goal of this study is to describe the population treated in these types of facilities in Spain and the therapeutic coverage given. The sample is made up of 215 young people in children's homes, of whom 93 are in TRC. The cases referred to TRC have been in residential care for less time but have gone through a greater number of placements. These young people also exhibit more problems of drug use, and there is a larger percentage of clinical‐range cases in the Child Behaviour Checklist scales of attention problems and aggressive behaviour. Nevertheless, the results of logistic regression indicate that the only variables that significantly increase the probability of being referred to TRC are drug use and changes of care placements. With regard to therapeutic care, there is a higher percentage in the TRC group receiving psychiatric care, and the sessions are also more frequent.