Efficient rank tests for semiparametric competing risk models

We consider a semiparametric competing risk model given by k independent survival times. The paper offers an asymptotic treatment of tests for the semiparametric null hypothesis of equality of the underlying risks. It turns out that modified rank tests are asymptotically efficient for certain semiparametric submodels, where the baseline hazard is a nuisance parameter. In addition, the asymptotic relative efficiency of the present tests is derived. A comparison of asymptotic power functions can then be used to classify various tests proposed earlier in the literature. For instance a chi-square type test is efficient for proportional hazards. Data driven tests of likelihood ratio type are proposed for cones of alternatives. We will consider certain stochastically increasing alternatives as a special example. The paper shows how the concept of local asymptotic normality of Le Cam works for hazard oriented models.     

The high cost of accurate knowledge

Many business thinkers believe it's the role of senior managers to scan the external environment to monitor contingencies and constraints, and to use that precise knowledge to modify the company's strategy and design. As these thinkers see it, managers need accurate and abundant information to carry out that role. According to that logic, it makes sense to invest heavily in systems for collecting and organizing competitive information. Another school of pundits contends that, since today's complex information often isn't precise anyway, it's not worth going overboard with such investments. In other words, it's not the accuracy and abundance of information that should matter most to top executives--rather, it's how that information is interpreted. After all, the role of senior managers isn't just to make decisions; it's to set direction and motivate others in the face of ambiguities and conflicting demands. Top executives must interpret information and communicate those interpretations--they must manage meaning more than they must manage information. So which of these competing views is the right one? Research conducted by academics Sutcliffe and Weber found that how accurate senior executives are about their competitive environments is indeed less important for strategy and corresponding organizational changes than the way in which they interpret information about their environments. Investments in shaping those interpretations, therefore, may create a more durable competitive advantage than investments in obtaining and organizing more information. And what kinds of interpretations are most closely linked with high performance? Their research suggests that high performers respond positively to opportunities, yet they aren't overconfident in their abilities to take advantage of those opportunities.     

Saving in Developing Countries: An Overview

This article reviews the current state of knowledge on the determinantsof saving rates, presenting the main findings and contributionsof the recently completed World Bank research project, ‘SavingAcross the World.’ The article discusses the basic designof the research project and its core database, the World SavingDatabase. It then summarizes the main project results and placesthem in the context of the literature on saving, identifyingthe key policy and nonpolicy determinants of private savingrates. Special attention is paid to the relationship betweengrowth and saving and the impact of specific policies on savingrates. The article concludes by introducing the studies includedin this special issue.     

Changing lifestyles and consumption patterns in developing countries: A scenario analysis for China and India

China and India are the world's largest developing economies and also two of the most populous countries. China, which now has more than 1.3 billion people, is expected to grow to more than 1.4 billion by 2050, and India with a population of 1 billion will overtake China to be the most populous country with about 1.6 billion population. These two countries are home to 37% of the world's population today. In addition, China and India have achieved notable success in their economic development characterised by a high rate of gross domestic product (GDP) growth in the last two decades. Together the two countries account already for almost a fifth of world GDP.The most direct and significant result of economic growth in India and China is the amazing improvement in quality of life (or at least spending power) for an increasing share of the population. The populations of both the countries have experienced a transition from ‘poverty’ to ‘adequate food and clothing’; today growing parts of the population are getting closer to ‘well to do lifestyles’. These segments of the society are not satisfied any more with enough food and clothes, but are also eager to obtain a quality life of high nutrient food, comfortable living, health care and other quality services.The theme of this paper is to analyse how the major drivers contributed to the environmental consequences in the past, and to take a forward look at the environmental impacts of these driving forces in China and India. The paper identifies population, affluence and technology to be the major driving forces in environmental pollution for these two countries then applies the simple equation of Impact=Population×Affluence×Technology, or I=PAT to evaluate the effects of changes in these drivers on CO₂ emissions.     

Discretionary monetary policy and the zero lower bound on nominal interest rates

Ignoring the existence of the zero lower bound on nominal interest rates one considerably understates the value of monetary commitment in New Keynesian models. A stochastic forward-looking model with an occasionally binding lower bound, calibrated to the U.S. economy, suggests that low values for the natural rate of interest lead to sizeable output losses and deflation under discretionary monetary policy. The fall in output and deflation are much larger than in the case with policy commitment and do not show up at all if the model abstracts from the existence of the lower bound. The welfare losses of discretionary policy increase even further when inflation is partly determined by lagged inflation in the Phillips curve. These results emerge because private sector expectations and the discretionary policy response to these expectations reinforce each other and cause the lower bound to be reached much earlier than under commitment.     

The analytics of search with posted prices

Summary. This paper investigates the characteristics of the optimal posted price in the standard sequential search paradigm. Much of the intuition gleaned from the extensive sequential search literature in which the seller adopts a reservation price does not carry over to the posted price setting. For example, an increase in buyer valuations can lead to a reduction in the optimal posted price. We do, however, provide sufficient conditions on the hazard rate function h which ensure that an increase in demand induces an increase in the optimal posted price. As exhibited herein, the analysis of the posted price model depends critically upon analytical properties of h. Amongst the issues treated are the elasticity of demand, finite horizon, sale of multiple units, and competitive equilibrium. Received: October 21, 1999; revised version: March 7, 2000     

Health Care Matters: Supply Chains In and Of the Health Sector

Providing health care involves a complex enterprise, and the trade‐off between quality and cost has been particularly stark compared to other industries. However, a recent focus on health sector supply networks is now producing significant innovations and improvements. This Special Topic Forum illustrates for the academic and practitioner community how health care supply chain research can benefit from our evolving understanding of supply chains and help push that understanding even further. We classify health care supply chain research into two broad categories—supply chain in health care and supply chain of health care—to set an agenda for future research.     

Meta-Functional Benefit Transfer for Wetland Valuation: Making the Most of Small Samples

This study applies functional Benefit Transfer via Meta-Regression Modeling to derive valuation estimates for wetlands in an actual policy setting of proposed groundwater transfers in Eastern Nevada. We illustrate how Bayesian estimation techniques can be used to overcome small sample problems notoriously present in Meta-functional Benefit Transfer. The highlights of our methodology are: (i) The hierarchical modeling of heteroskedasticity; (ii) The ability to incorporate additional information via refined priors; and (ii) The derivation of measures of model performance with the corresponding option of model-averaged Benefit Transfer predictions. Our results indicate that economic losses associated with the disappearance of these wetlands can be substantial and that primary valuation studies are warranted.      

Profitability and capital accumulation in British industry during the transwar period, 1913–1924

This article provides new information on profitability, taxation, and capital accumulation across the transwar period, based on an analysis of the accounting records of 30 companies in a range of industrial sectors. The main findings, that apparently high profitability in the war period was largely an illusion, and that the subsequent slump was very severe in its effects on business profitability, are consistent with views of the period as one of low capital accumulation. In effect, the generosity of the state's negotiating position towards capital owners during the war was cancelled out by the combined effects of inflation and of the severe postwar slump.