Partitioned log-rank tests for the overall homogeneity of hazard rate functions

In survival analysis, it is routine to test equality of two survival curves, which is often conducted by using the log-rank test. Although it is optimal under the proportional hazards assumption, the log-rank test is known to have little power when the survival or hazard functions cross. To test the overall homogeneity of hazard rate functions, we propose a group of partitioned log-rank tests. By partitioning the time axis and taking the supremum of the sum of two partitioned log-rank statistics over different partitioning points, the proposed test gains enormous power for cases with crossing hazards. On the other hand, when the hazards are indeed proportional, our test still maintains high power close to that of the optimal log-rank test. Extensive simulation studies are conducted to compare the proposed test with existing methods, and three real data examples are used to illustrate the commonality of crossing hazards and the advantages of the partitioned log-rank tests.     

The effect of fast and slow decisions on risk taking

We experimentally compare fast and slow decisions in a series of experiments on financial risk taking in three countries involving over 1700 subjects. To manipulate fast and slow decisions, subjects were randomly allocated to responding within 7 seconds (time pressure) or waiting for at least 7 or 20 seconds (time delay) before responding. To control for different effects of time pressure and time delay on measurement noise, we estimate separate parameters for noise and risk preferences within a random utility framework. We find that time pressure increases risk aversion for gains and risk taking for losses compared to time delay, implying that time pressure increases the reflection effect of Prospect Theory. The results for gains are weaker and less robust than the results for losses. We find no significant difference between time pressure and time delay for loss aversion (tested in only one of the experiments). Time delay also leads to less measurement noise than time pressure and unconstrained decisions, and appears to be an effective way of decreasing noise in experiments.     

Heading South: Time to Abandon the ‘Parallel Worlds’ of International Non-Governmental Organization (NGO) and Domestic Third Sector Scholarship?

Since third sector research emerged as a full-fledged interdisciplinary academic field during the late 1980s, a separation has usually been maintained—in common with many other social science disciplines—between communities of researchers who are primarily concerned with the study of the third sector in rich Western countries and those who work on the third sector in the so-called developing world. Whilst internationally focused researchers tend to use the language of ‘non-governmental organizations’, those in domestic settings usually prefer the terms ‘non-profit organization’ or ‘voluntary organization’, even though both subsectors share common principles and are equally internally diverse in terms of organisations and activities. Whilst there has long been common-sense logic to distinguishing between wealthier and poorer regions of the world based on differences in the scale of human need, the ‘developed’ versus ‘developing’ category can also be criticised as being rather simplistic and unhelpfully ideological. As the categories of ‘developing’ and ‘developed’ countries become less clear-cut, and global interconnectedness between third sectors and their ideas grows, this paper argues that we need to reconsider the value of maintaining these parallel worlds of research, and instead develop a more unified approach.     

A Comparative Pharmacokinetic Estimate of Mercury in U.S. Infants Following Yearly Exposures to Inactivated Influenza Vaccines Containing Thimerosal

The use of thimerosal preservative in childhood vaccines has been largely eliminated over the past decade in the United States because vaccines have been reformulated in single‐dose vials that do not require preservative. An exception is the inactivated influenza vaccines, which are formulated in both multidose vials requiring preservative and preservative‐free single‐dose vials. As part of an ongoing evaluation by USFDA of the safety of biologics throughout their lifecycle, the infant body burden of mercury following scheduled exposures to thimerosal preservative in inactivated influenza vaccines in the United States was estimated and compared to the infant body burden of mercury following daily exposures to dietary methylmercury at the reference dose established by the USEPA. Body burdens were estimated using kinetic parameters derived from experiments conducted in infant monkeys that were exposed episodically to thimerosal or MeHg at identical doses. We found that the body burden of mercury (AUC) in infants (including low birth weight) over the first 4.5 years of life following yearly exposures to thimerosal was two orders of magnitude lower than that estimated for exposures to the lowest regulatory threshold for MeHg over the same time period. In addition, peak body burdens of mercury following episodic exposures to thimerosal in this worst‐case analysis did not exceed the corresponding safe body burden of mercury from methylmercury at any time, even for low‐birth‐weight infants. Our pharmacokinetic analysis supports the acknowledged safety of thimerosal when used as a preservative at current levels in certain multidose infant vaccines in the United States.     

Understanding the Dynamics of the Individual Donor’s Trust Damage in the Philanthropic Sector

Although trust is long known to be critical to predict behaviors in a charitable context, little research has examined trust damage and its effects on giving behavior. Trust damage is an intermediate state between trust and distrust, rather than a simple reversal or extension, and can change over time. Our research explores individual donor’s trust damage through a dynamic evolution. Across the longitudinal survey, we conclude that the trust damage of pre-giving, giving, and post-giving stage plays different roles in the decision-making process. Trust damage does not play a direct role in the giving intention, but it can indirectly affect giving intention through its impact on perceived benefit and perceived risk. Individual donor’s satisfaction has a strong effect on post-giving trust or continual trust damage, which in turn positively affects future giving intention and behavior. Several important insights for practitioners in the nonprofit sector are also discussed.     

Organisationskultur im Spielfilm

By analyzing cinema films, specific organizational cultures can be illustrated. The culture of prison as a “total institution” is explained on the basis of the movie “The Shawshank Redemption” (1994). With regard to the developing friendship between the former banker Andy Dufresne who is innocently convicted and the homicide delinquent Ellis Boyd Redding typical characteristics of a total institution are pointed out. Furthermore, the psychological function those characteristics serve for employees, inmates and even for the society as a whole is analyzed. Central to this interpretation is thinking of the prison as a father substitute. Many interactions become comprehensible viewed in this context. Additionally, the prison represents a huge object of projection which facilitates the collective release of aggression.     

The Meaning of Trust for Brazilians with Higher Education

The validity of the World Values Survey (WVS) question used to measure trust is disputed over and this article is intended to present the results of an online survey, conducted in Brazil, which tested the meaning of the term trust in the WVS question. The surveyed population is entirely Brazilian and the majority has received some form of higher education. The results of the survey partially corroborate the validity of the WVS and partially deny it. Within the results of this survey there are predominantly two dominant perspectives represented within the surveyed population including: respondents who think in friends and relatives as part of most people have a higher probability of also saying to trust most people which means that different people may be answering slightly different questions. However, respondents who say that trust most people have higher levels of trust in people in general than in family if compared with respondents who say to not trust most people which is in accordance with the expectation that the question adequately measures generalized interpersonal trust.