Semiparametric Efficient Estimation in the Generalized Odds-Rate Class of Regression Models for Right-Censored Time-to-Event Data

The generalized odds-rate class of regression models for time to event data is indexed by a non-negative constant and assumes thatg(S(t|Z)) = (t) + Zwhere g(s) = log(^-1(s-) for > 0, g₀(s) = log(- log s), S(t|Z) is the survival function of the time to event for an individual with qx1 covariate vector Z, is a qx1 vector of unknown regression parameters, and (t) is some arbitrary increasing function of t. When =0, this model is equivalent to the proportional hazards model and when =1, this model reduces to the proportional odds model. In the presence of right censoring, we construct estimators for and exp((t)) and show that they are consistent and asymptotically normal. In addition, we show that the estimator for is semiparametric efficient in the sense that it attains the semiparametric variance bound.     

Profiles of Housing Cost Burden in the United States

In this study, the ordered logistic regression model indicates that renters suffer a greater housing cost burden than homeowners and that the lower the income of the household, the larger the portion of income that is spent for housing. Further, the model also shows that the burden of high housing costs falls disproportionately on certain groups of American households. Compared to the reference group, two single-risk groups (Asian-American households and households with three or more children) and two dual-risk groups (female-headed households with three or more children and minority households with three or more children) tend to have a higher risk of excessive housing costs. Elderly households and three elderly-related groups (female-headed elderly households, minority elderly households, and female-headed minority elderly households), however, tend to have a lower risk of housing cost burden than other households. The housing cost burden of the reference group is comparable to the housing cost burden of each of the following groups: for single female-headed households; Black households; Hispanic households; and female-headed minority households. The policy implications of these findings are discussed in the paper.     

Dynamic Risk Management Systems: Hybrid Architecture and Offshore Platform Illustration

This paper describes and illustrates the architecture of computer-based Dynamic Risk Management Systems (DRMS) designed to assist real-time risk management decisions for complex physical systems, for example, engineered systems such as offshore platforms or medical systems such as patient treatment in Intensive Care Units. A key characteristic of the DRMSs that we describe is that they are hybrid, combining the powers of Probabilistic Risk Analysis methods and heuristic Artificial Intelligence techniques. A control module determines whether the situation corresponds to a specific rule or regulation, and is clear enough or urgent enough for an expert system to make an immediate recommendation without further analysis of the risks involved. Alternatively, if time permits and if the uncertainties justify it, a risk and decision analysis module formulates and evaluates options, including that of gathering further information. This feature is particularly critical since, most of the time, the physical system is only partially observable, i.e., the signals observed may not permit unambiguous characterization of its state. The DRMS structure is also dynamic in that, for a given time window (e.g., 1 day or 1 hour), it anticipates the physical system's state (and, when appropriate, performs a risk analysis) accounting for its evolution, its mode of operations, the predicted external loads and problems, and the possible changes in the set of available options. Therefore, we specifically address the issue of dynamic information gathering for decision-making purposes. The concepts are illustrated focusing on the risk and decision analysis modules for a particular case of real-time risk management on board offshore oil platforms, namely of two types of gas compressor leaks, one progressive and one catastrophic. We describe briefly the DRMS proof-of-concept produced at Stanford, and the prototype (ARMS) that is being constructed by Bureau Veritas (Paris) based on these concepts.     

Business Legitimacy among Business Students in the United States, Great Britain, and South Africa

This study compares attitudes toward business legitimacy in three countries. Positive attitudes toward business legitimacy exist when there is a congruence between organizational activities and societal expectations. Businesses are concerned about the extent to which negative attitudes toward business legitimacy will lead to increased government regulation. The results suggest that business students in all three countries are similar in their attitudes toward business legitimacy; however, blacks have more negative attitudes toward business legitimacy than do whites. This study resulted in the validation of a scale that can be used to measure attitudes toward business legitimacy on a cross-cultural basis. Business legitimacy is a major concern in South Africa as the predominately white business community seeks to give the emerging black majority a stake in the existing economic system. This revised version was published online in August 2006 with corrections to the Cover Date.     

State versus Market: Contending Interests in the Struggle to Control French Accounting Standardisation

The paper concerns the struggle between different interest groups to control or significantly influence the objectives, institutional arrangements and processes of French accounting standardisation. Its particular focus of interest is the state agency established to deal with standardisation, namely the National Accounting Council, the Conseil National de la Comptabilité (CNC), and its predecessors. The period addressed spans from 1941 to the present, marked by the first attempt to implement a national accounting code, adoption of the initial post-war code in 1947 and subsequent revisions.The paper identifies and examines the role played by the French state in establishing an institutional structure for accounting standardisation and in seeking to influence operation of that structure as a means to achieve a concertation of diverse social and economic interest groups with an interest in accounting standards. The objective for the process from the viewpoint of the state has been seen as the intended dominance of certain interests of state over other interests, whether public sector or otherwise. In the course of time, the dominant interests of the state have changed in the face of changing expectations about the role of financial accounting and reporting in the financial life of France. The role of the state is seen to have come under increasing pressure from private sector interests in France and externally. Particular attention is given to the 1996–8 major reforms to the CNC and associated new regulatory structure.The possibility is assessed of whether and under what terms the French approach to accounting standardisation can be sustained, grounded as it is in a profound attachment by the state to the values of the Etat colbertiste.     

The carrying capacity of a region: A planning model

While traditional planning often assumes unlimited growth potential, in reality such growth has absolute limits in terms of resources available and maintenance of the ecosystem. These limits (the region's carrying capacity) can be modeled; one such model, the State-of-the-System (SOS) Model, is described in this paper and is designed to test various assumptions about the desired growth of an area under explicit side conditions or limitations. Such a model could be used to test the validity of establishing comprehensive plans, to identify critical growth constraints, and to weight policy choices.     

Surviving the Holocaust: Socio-demographic Differences Among Amsterdam Jews

This study determined the victimisation rate among Amsterdam Jews and socio-demographic differences in surviving the Holocaust. After linking a registration list of over 77,000 Jewish inhabitants in 1941 to post-war lists of Jewish victims and survivors, the victimisation rate lies between 74.3 and 75.3 %. Differences in survival chances and risk of being killed are examined by using multivariable logistic and Cox regression analyses. While male Jews had a reduced risk of death, in the end their survival chances hardly differed from females. Though Jews aged 6–14 and 31–50 initially had a lower risk of death, in the end compared with Jews aged 15–30 they had lower survival chances, just as Jews aged 50+. For Jews aged 0–5, it was the other way around. Immigrants showed better survival chances than native Jews. German Jews showed better survival chances than Dutch Jews, but Polish and other Jewish nationals showed highest survival chances. Jews who had abandoned Judaism had better survival chances than Jews belonging to an Israelite congregation. Divorced, widowed and unmarried adult Jews had better survival chances than married Jews and their children; Jews married to non-Jews, however, had one of the highest survival chances. Jews in the two highest social classes had better survival chances than jobless Jews. These findings indicate that survival was not random but related to socio-demographic characteristics. This sheds light on demographic consequences of conflict and violence: Nazi persecution reduced the Amsterdam Jewish community drastically, and socio-demographic differences in survival impacted the post-war Jewish population structure.     

Evidence‐based Management in Practice: Opening up the Decision Process,Decision‐maker and Context

Evidence‐based management (EBM) has been subject to a number of persuasive critiques in recent years. Concerns have been raised that: EBM over‐privileges rationality as a basis for decision‐making; ‘scientific’ evidence is insufficient and incomplete as a basis for management practice; understanding of how EBM actually plays out in practice is limited; and, although ideas were originally taken from evidence‐based medicine, individual‐situated expertise has been forgotten in the transfer. To address these concerns, the authors adopted an approach of ‘opening up’ the decision process, the decision‐maker and the context (Langley et al. ( 1995 ). ‘Opening up decision making: the view from the black stool’, Organization Science, 6, pp. 260–279). The empirical investigation focuses on an EBM decision process involving an operations management problem in a hospital emergency department in Australia. Based on interview and archival research, it describes how an EBM decision process was enacted by a physician manager. It identifies the role of ‘fit’ between the decision‐maker and the organizational context in enabling an evidence‐based process and develops insights for EBM theory and practice.     

Occupational Attainment and Earnings: The Case of the Disabled

Abstract. This paper offers, for the first time, an investigation of wage differentials between disabled and non‐disabled workers in Sweden. It extends the traditional wage decomposition by incorporating explained and unexplained differences in occupational attainment. Data from the Swedish Level of Living Survey for 1981 and for 1991 have been used. The results show that in both years the disabled worked in low‐level occupations to a greater extent relative to the non‐disabled. This is due to the fact that disabled workers have lower qualifications. The unexplained component due to differences in returns on wage determinants is insignificant in the 1981 case but is highly significant in 1991, constituting around 50–60 per cent of the average log wage differential.