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.     

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.     

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.     

Female labour force participation and second birth rates in South Korea

In recent decades, while female labour force participation rates in South Korea have increased, the country’s total fertility rates have declined dramatically. This study explores the association between women’s labour force participation and second birth rates in South Korea over the period 1980–2006. An event-history analysis is applied to longitudinal data from waves 1–10 of the Korea Labour and Income Panel Study. The study shows that post-birth labour force participation significantly reduced women’s propensity for having a second child, whereas non-employment after first birth was associated with an increased propensity. Women with highly educated husbands had a higher likelihood of enlarging the family. Further, the second birth trend in Korea fluctuated in tandem with the country’s institutional and socio-economic development. The childbearing propensity of homemakers was especially sensitive to the business cycle.     

Building Health Insurance Literacy: Evidence from the Smart Choice Health Insurance™ Program

With the passage of the Patient Protection and Affordable Care Act (ACA) of 2010, the health insurance literacy of Americans became a critical issue. In response, a consumer education program was created and tested by university researchers and educators associated with Cooperative Extension. This article draws extensively on the emerging literature on health insurance literacy and on data from participants in the Smart Choice Health Insurance? program. The intent of the study was to understand socio-demographic and environmental variables that predict initial health insurance literacy and gains in health insurance literacy. A standardized instrument measuring health insurance literacy was used to collect the data. Multivariate analysis showed higher income consumers demonstrated greater initial health insurance literacy scores compared to middle income consumers, whereas younger, male and lower educated consumers reported lower initial health insurance literacy. After participating in the Smart Choice Health Insurance? program, consumers who made greater gains in their health insurance literacy tended to be female, higher income, and consumers residing in states that showed supportiveness of the ACA. The findings highlight the importance of considering sociodemographic characteristics in program design and delivery, as well as how contextual issues, such as the political environment, might impact the delivery of educational efforts. Findings from the analyses help inform ways to adapt and tailor educational opportunities that focus on health insurance literacy for a range of consumers.     

Ambiguity aversion in multi-armed bandit problems

In multi-armed bandit problems, information acquired from experimentation is valuable because it tells the agent whether to select a particular option again in the future. This article tests whether people undervalue this information because they are ambiguity averse, or have a distaste for uncertainty about the average quality of each alternative. It is shown that ambiguity averse agents have lower than optimal Gittins indexes, appearing to undervalue information from experimentation, but are willing to pay more than ambiguity neutral agents to learn the true mean of the payoff distribution, appearing to overvalue objectively given information. This prediction is tested with a laboratory experiment that elicits a Gittins index and a willingness to pay on six two-armed bandits. Consistent with the predictions of ambiguity aversion, the Gittins indexes are significantly lower than optimal and willingnesses to pay are significantly higher than optimal.     

Führung in Familienunternehmen: Besonderheiten der Entscheidungsfindung und Verhaltenssteuerung und deren Auswirkung auf den Unternehmenserfolg

This paper draws on a survey design to investigate whether family ownership and leadership have an influence on the decision-facilitating and decision-influencing roles of management control. Moreover, we investigate whether the more intuitive decision making in family firms which is often said to be caused by a lack of professionalism, is indeed a disadvantage. The results indicate significant differences in the use of management controls between family firms and non-family firms. However, in contrast to the prevailing view in literature, the performance of family firms is not affected negatively by their specific way of making decisions and by their more centralized management style. According to our data, the prevailing characterization of family firms as being less professionally managed seems questionable.     

Have Labor Market Reforms at the Turn of the Millennium Changed the Job and Employment Durations of new Entrants?

Many European countries during the 1990s and early 2000s tried to raise labor market flexibility by relaxing their employment protection legislation. This paper investigates whether the reforms have influenced job and employment stability for labor market entrants in Germany and Italy. Duration models are estimated using comparable administrative data for the two countries. The results provide, to some extent, evidence of a decrease in job stability. However, this is not accompanied by a compensating increase in employment stability during the first 3 years after labor market entry.     

Global Health Volunteering; Understanding Organizational Goals

This paper examines the goals of organizations that sponsor short-term volunteer trips in global health, whether they be NGO’s, faith-based, educational, or corporate organizations. Results from a U.S.-based national survey of 177 such organizations and 27 interviews with trip organizers suggest that organizations often sponsor volunteer trips to achieve goals that are quite different from the improvement of health outcomes in poor countries. While providing health services is often cited as the most important goal, volunteer activity is also considered important in enhancing the organizations’ reputation, recruitment and retention, and financial well-being. The prominence of other goals has the potential for diverting resources and focus from what is presumably the primary purpose of serving host communities in the most effective manner possible.