A review and discussion of prospective statistical surveillance in public health

Summary. A review of methods suggested in the literature for sequential detection of changes in public health surveillance data is presented. Many researchers have noted the need for prospective methods. In recent years there has been an increased interest in both the statistical and the epidemiological literature concerning this type of problem. However, most of the vast literature in public health monitoring deals with retrospective methods, especially spatial methods. Evaluations with respect to the statistical properties of interest for prospective surveillance are rare. The special aspects of prospective statistical surveillance and different ways of evaluating such methods are described. Attention is given to methods that include only the time domain as well as methods for detection where observations have a spatial structure. In the case of surveillance of a change in a Poisson process the likelihood ratio method and the Shiryaev–Roberts method are derived.     

Maneuvering through Hostile Environments: How Firms Leverage Product and Process Innovativeness

Is focusing on innovativeness the appropriate organizational response in hostile environments? This study addresses four distinct forms of hostile environments: market decline, restrictiveness, competition, and resource scarcity. The research draws on contingency theory to explain how these forms of hostility affect product innovativeness, process innovativeness, and firm performance. While the extant literature has investigated the effects of hostile environments on performance, little has been done to distinguish between different forms of hostility and, in turn, their potential effect on product and process innovativeness. We argue that investments in product and process innovativeness are either fostered or hindered, contingent on the form of hostile pressures from the external operating environment. These firm responses should in turn suppress the negative effects of hostility on performance. A survey using newly developed measurement scales for hostile environments was used to collect data from 148 small and medium‐sized manufacturing plants. The results provide evidence that generally supports our hypotheses. More specifically, the direct effects of the four forms of hostile environments impact product and process innovativeness differently. Likewise, the suppression and consistent mediation effects of product and process innovativeness differ depending upon the type of hostile environment, suggesting that manufacturers consider applying these capabilities contingent upon the type of hostile climate they face. Therefore, to understand how firms leverage product and process innovativeness, hostile environments are best differentiated into categories rather than being aggregated.     

南宋时期的《中庸》与道统——历史与学术背景

由于“中”“庸”两词语义上的模糊性,其哲学含义颇为复杂。从郑玄到二程、吕祖谦,尤其是朱熹,都对“中庸”进行了解释,现代学者对《中庸》书名的释义更是多种多样。对于《中庸》的时代以及与子思的关系问题,中国历代学者以及西方的汉学家都提出了不同的观点,至今仍然莫衷一是。     

Aging With Rising Risk: Have Older Households Experienced Faster-Growing Risk Exposure Than Younger Ones Since the 1990s?

Financial markets have been characterized by boom and bust cycles since the 1980s, while the responsibility for managing retirement wealth has increasingly shifted onto individual households at the same time. Policy makers and experts have expressed concern over rising risk exposure among older householders, who appear to be increasingly exposed to the growing financial risks just as they near retirement. We consider household data from the Federal Reserve’s Survey of Consumer Finances from 1989 to 2010 to analyze the correlation between age and risk exposure. We test whether older householders’ risk exposure has indeed grown over time, whether it has increased more than that of younger householders, whether changes in the demographic composition of older householders have contributed to older households’ rising risk exposure, and the degree to which increases in risk exposure can be traced to a growing concentration of household assets held in stocks and housing and to rising householder indebtedness. Our results indicate that risk exposure has grown more for older householders than for younger ones, that demographic changes among older householders have contributed to additional increases in older householders’ risk exposure, and that the growth of older householders’ risk exposure is driven more by rising risky asset concentration and less by greater indebtedness.     

Multivariate hypothesis testing using generalized and {2}-inverses – with applications

The use of generalized inverses in Wald's-type quadratic forms of test statistics having singular normal limiting distributions does not guarantee to obtain chi-square limiting distributions. In this article, the use of {2} -inverses for that problem is investigated. Alternatively, Imhof-based test statistics can also be defined, which converge in distribution to weighted sum of chi-square variables. The asymptotic distributions of these test statistics under the null and alternative hypotheses are discussed. Under fixed and local alternatives, the asymptotic powers are compared theoretically. Simulation studies are also performed to compare the exact powers of the test statistics in finite samples. A data analysis on the temperature and precipitation variability in the European Alps illustrates the proposed methods.