Motivated by a breast cancer research program, this paper is concerned with the joint survivor function of multiple event times when their observations are subject to informative censoring caused by a terminating event. We formulate the correlation of the multiple event times together with the time to the terminating event by an Archimedean copula to account for the informative censoring. Adapting the widely used two-stage procedure under a copula model, we propose an easy-to-implement pseudo-likelihood based procedure for estimating the model parameters. The approach yields a new estimator for the marginal distribution of a single event time with semicompeting-risks data. We conduct both asymptotics and simulation studies to examine the proposed approach in consistency, efficiency, and robustness. Data from the breast cancer program are employed to illustrate this research.
ABSTRACTThe cost and time of pharmaceutical drug development continue to grow at rates that many say are unsustainable. These trends have enormous impact on what treatments get to patients, when they get them and how they are used. The statistical framework for supporting decisions in regulated clinical development of new medicines has followed a traditional path of frequentist methodology. Trials using hypothesis tests of “no treatment effect” are done routinely, and the p-value < 0.05 is often the determinant of what constitutes a “successful” trial. Many drugs fail in clinical development, adding to the cost of new medicines, and some evidence points blame at the deficiencies of the frequentist paradigm. An unknown number effective medicines may have been abandoned because trials were declared “unsuccessful” due to a p-value exceeding 0.05. Recently, the Bayesian paradigm has shown utility in the clinical drug development process for its probability-based inference. We argue for a Bayesian approach that employs data from other trials as a “prior” for Phase 3 trials so that synthesized evidence across trials can be utilized to compute probability statements that are valuable for understanding the magnitude of treatment effect. Such a Bayesian paradigm provides a promising framework for improving statistical inference and regulatory decision making. 相似文献
From the inception of the proportional representation movement it has been an issue whether larger parties are favored at
the expense of smaller parties in one apportionment of seats as compared to another apportionment. A number of methods have
been proposed and are used in countries with a proportional representation system. These apportionment methods exhibit a regularity
of order, as discussed in the present paper, that captures the preferential treatment of larger versus smaller parties. This
order, namely majorization, permits the comparison of seat allocations in two apportionments. For divisor methods, we show
that one method is majorized by another method if and only if their signpost ratios are increasing. This criterion is satisfied
for the divisor methods with power-mean rounding, and for the divisor methods with stationary rounding. Majorization places
the five traditional apportionment methods in the order as they are known to favor larger parties over smaller parties: Adams,
Dean, Hill, Webster, and Jefferson.
Received: 5 August 2000/Accepted: 24 October 2001 相似文献
This article places an episode in the history of sociological theory into intellectual history in the twentieth century. The
perspective is chronological as well as contextual. The themes are two theoretical approaches, both embedded in both American
and German history, Parsonian Systems Theory and “Frankfurt School” Critical Theory. The chronology shown spanned mainly from
the 1940s to the 1960s. The context of the two theories is a period that is crucial in twentieth century history. The protagonists
of the two approaches were, in the 1940s, Americans and Germans exiled in the United States. In the 1950s, both approaches
were affected by McCarthyism in different ways. The 1960s, however, were the culmination. The dynamics of the two approaches
led into a schism which came into the open on the occasion of the 1964 German Sociology Conference in Heidelberg celebrating
Max Weber. The article shows the stages in the evolution of the schism, emulating three acts in a drama. The final split was
over whether Weber or Marx should be the classic whose oeuvre was to influence sociological thinking today. My aim is to exemplify
how these two authoritative approaches in sociological theory, far from escaping the vagaries and vicissitudes of their times,
were embedded in twentieth-century history. 相似文献
Athletics is the most prominent extracurricular activity in U.S. secondary schools in terms of student participation and school budgets. The latter is often justified on the grounds that healthy bodies produce healthy minds, that school sports boost school spirit, and that participation in school-based sports increases students' self-esteem. In this article we examine the interrelationships among participation in a school-based sport and the benefits assumed to be associated with it. Specifically, we test a model that postulates that school spirit, operationalized as attachment to school, and healthy bodies, operationalized as a sense of physical well-being, mediate the relationship between school sports and self-esteem. Data from the National Longitudinal Study of Adolescent Health on Caucasian and African American girls and boys were employed to test the model. School attachment and physical well-being absorbed the statistical effect of participating in a sport for all four gender-by-race groups. Among Caucasian girls a negative residual effect of sports participation was observed, which suggests that sports participation encapsulates multiple effects with contradictory influences. For African American girls school attachment by itself was not a significant mediator of the effect of sports participation on self-esteem. For all groups a sense of physical well-being was the more powerful mediator. 相似文献
In light of use by airline unions of partial-strike tactics, such as concerted refusals to bid for overtime work and so-called
” CHAOS” tactics involving unannounced refusals to fly after passengers have been ticketed and are ready to board, the authors
examine whether the Railway Labor Act (RLA) should be interpreted to permit employers to discipline employees for engaging
in such tactics, or whether these are a protected form of economic pressure. Although in many respects bargaining duties and
economic weapons under the RLA are read consonant with precedents under the National Labor Relations Act (NLRA) (which governs
all industries other than rail and air transport), there are a few decisions suggesting that during the period when self-help
may be resorted to, employees can engage in partial strike activities as long as they violate no court order but are subject
to permanent replacement in limited circumstances. These decisions, the authors submit, fail to take account of Supreme Court
decsions since the 1930s that some economic pressures by unions, such as slowdowns and sitins, may not violate the labor laws
but nor are they protected by those laws so as to immunize partial strikers from employer discipline. These decisions are
not based on unique features of the NLRA. Rather, they give recognition to the background assumptions of Congress that employers
may act to protect their property interests as long as they do not run afoul of NLRA or RLA protections and that employees
who engage in partial-strike activities are subject to employer discipline even where not strictly necessary to maintain operations.
Moreover, these tactics skew the bargaining process by giving employees an essentially risk-free gambit to pressure their
economic position through planned disruption of carrier operations.
Professor Estreicher is also labor and employment counsel to O’Melveny & Myers, LLP. The views expressed herein are the authors’
and should not be attributed to any organization. Hannah Breshin and Tom Jerman of O’Melveny & Myers, assisted the authors
with this article. We also thank Professor Herbert Northrup for his helpful comments. 相似文献
Concurrent and longitudinal associations between peer crowd affiliation and internalized distress were examined in a sample of 246 youth (148 girls, 98 boys). Children completed measures of depression, social anxiety, loneliness, and self‐esteem when they were in grades 4 to 6 (Time 1), and again 6 years later during adolescence (grades 10 – 12; Time 2). At Time 2, adolescents also reported their self‐concept and their identification with reputation‐based peer crowds, including Populars, Jocks, Brains, Burnouts, Non‐Conformists, and None/Average crowds. Results indicated that adolescents' report of peer crowd affiliation was concurrently associated with self‐concept and levels of internalizing distress. Follow‐back analyses of internalizing trajectories revealed that Populars/Jocks had experienced significant declines in internalizing distress across development, whereas Brains exhibited some increases in internalizing distress between childhood and adolescence. 相似文献