A note on sample size savings with the use of a single well‐controlled clinical trial to support the efficacy of a new drug

In terms of the risk of making a Type I error in evaluating a null hypothesis of equality, requiring two independent confirmatory trials with two‐sided p‐values less than 0.05 is equivalent to requiring one confirmatory trial with two‐sided p‐value less than 0.001 25. Furthermore, the use of a single confirmatory trial is gaining acceptability, with discussion in both ICH E9 and a CPMP Points to Consider document. Given the growing acceptance of this approach, this note provides a formula for the sample size savings that are obtained with the single clinical trial approach depending on the levels of Type I and Type II errors chosen. For two replicate trials each powered at 90%, which corresponds to a single larger trial powered at 81%, an approximate 19% reduction in total sample size is achieved with the single trial approach. Alternatively, a single trial with the same sample size as the total sample size from two smaller trials will have much greater power. For example, in the case where two trials are each powered at 90% for two‐sided α=0.05 yielding an overall power of 81%, a single trial using two‐sided α=0.001 25 would have 91% power. Copyright © 2004 John Wiley & Sons, Ltd.     

Asian Transnational Families in New Zealand: Dynamics and Challenges

Since the 1990s, Asia has emerged as the major contributor of migration flows into New Zealand. Settler migration, tourism, international business and more recently, international education make up the diverse flows of Asian peoples into the country. This paper explores the changing dynamics of Asian transnational families over the last two decades, with a special focus on the experiences of young people within these families. In the early 1990s, bi-local families were commonly known as "astronaut" families, in which one or both parents returned to their countries of origin to work, leaving their children to be educated in New Zealand. Over time the structures of these families have changed, as many young migrants relocated back to their former homeland or re-migrated to a third country, while "astronaut parents" rejoined their spouses either in the origin or destination. More recently, the educational migration of international students from countries in Asia has given rise to another form of transnational family, in which young people enter New Zealand as international students and some subsequently become residents. In this paper, the experiences of these young people are explored within the wider context of family strategies for maximising benefits through spatially extended networks on the one hand, and government initiatives and immigration policy changes that have been taking place in New Zealand since the 1990s on the other.     

Consumer-Phase Salmonella enterica serovar Enteritidis Risk Assessment for Egg-Containing Food Products

We describe a one-dimensional probabilistic model of the role of domestic food handling behaviors on salmonellosis risk associated with the consumption of eggs and egg-containing foods. Six categories of egg-containing foods were defined based on the amount of egg contained in the food, whether eggs are pooled, and the degree of cooking practiced by consumers. We used bootstrap simulation to quantify uncertainty in risk estimates due to sampling error, and sensitivity analysis to identify key sources of variability and uncertainty in the model. Because of typical model characteristics such as nonlinearity, interaction between inputs, thresholds, and saturation points, Sobol's method, a novel sensitivity analysis approach, was used to identify key sources of variability. Based on the mean probability of illness, examples of foods from the food categories ranked from most to least risk of illness were: (1) home-made salad dressings/ice cream; (2) fried eggs/boiled eggs; (3) omelettes; and (4) baked foods/breads. For food categories that may include uncooked eggs (e.g., home-made salad dressings/ice cream), consumer handling conditions such as storage time and temperature after food preparation were the key sources of variability. In contrast, for food categories associated with undercooked eggs (e.g., fried/soft-boiled eggs), the initial level of Salmonella contamination and the log10 reduction due to cooking were the key sources of variability. Important sources of uncertainty varied with both the risk percentile and the food category under consideration. This work adds to previous risk assessments focused on egg production and storage practices, and provides a science-based approach to inform consumer risk communications regarding safe egg handling practices.     

HOW DO ELECTORAL SYSTEMS AFFECT FISCAL POLICY? EVIDENCE FROM CANTONAL PARLIAMENTS, 1890–2000

Using a new data set on Swiss cantons since 1890, we analyze how the adoption of proportional representation affects fiscal policy. In line with economic theory, we show that proportional systems shift spending toward broad goods (like education and welfare benefits) but decrease spending on geographically targetable goods (like roads). We find little evidence that proportional representation increases the overall size of government. An analysis of the underlying theoretical mechanisms reveals that proportional representation increases electoral turnout, left‐wing representation, and political fragmentation. These changes in political representation explain a substantial share of the rise in education spending, but a small share of the rise in welfare spending or the decline in road expenditures.     

Daily Variation in Adolescents' Sleep,Activities, and Psychological Well‐Being

The daily diary method was used to examine the daily dynamics of adolescent sleep time, activities, and psychological well‐being among an ethnically diverse sample of over 750 adolescents approximately 14–15 years of age. Studying and stressful demands during the day were modestly but consistently associated with less sleep that evening. Receiving less sleep at night, in turn, was modestly but consistently related to higher levels of anxiety, depressive feelings, and fatigue during the following day. In addition, the daily variability in adolescents' sleep time was notable and just as important for the youths' average levels of daily psychological well‐being as was the average amount of time spent sleeping each night. A small number of ethnic and gender differences emerged in the dynamics of adolescent sleep, activities, and well‐being. Discussion focuses on the importance of examining variability in adolescents' sleep behaviors in order to better understand the implications of sleep for adolescent well‐being and development.     

Top Team Diversity,Internationalization and the Mediating Effect of International Alliances*

This study examines the mediating effect of international alliances for the relationship between TMT (top management team) job‐related diversity (educational, functional background, outside industry experience and international exposure) and firm internationalization. We argue that firms with greater TMT diversity will use more international alliances, resulting in higher firm internationalization. Based on a sample of 226 US firms during the period 1988–1994, we find that international alliances partially mediate the relationship between TMT international exposure diversity and firm internationalization. However, we do not find international alliances to mediate the relationships between other forms of TMT diversity and firm internationalization. We discuss implications and directions for future research.     

Employment and the Risk of Domestic Abuse Among Low‐Income Women

This paper uses data from 2 randomized evaluations of welfare‐to‐work programs—the Minnesota Family Investment Program and the National Evaluation of Welfare‐to‐Work Strategies—to estimate the effect of employment on domestic abuse among low‐income single mothers. Unique to our analysis is the application of a 2‐stage least squares method, in which random assignment enables us to control for omitted characteristics that might otherwise confound the association between employment and domestic abuse. We find that increased maternal employment decreases subsequent reports of domestic abuse in both studies. In the Minnesota Family Investment Program—a program with an enhanced income disregard that allowed welfare mothers to keep a portion of their welfare income as earnings rose—an increase in household incomes appears to have contributed to reductions in reports of domestic abuse.     

FAMILY STRUCTURE, CLOSENESS TO RESIDENTIAL AND NONRESIDENTIAL PARENTS, AND PSYCHOLOGICAL DISTRESS IN EARLY AND MIDDLE ADOLESCENCE

American adolescents currently live in a variety of different family structures, with the vast majority of adolescents living in intact, blended, divorced, and never-married families. Previous research shows that family structure correlates both with the quality of parent–adolescent relationships and adolescent psychological distress. The quality of parent–adolescent relationships also correlates with adolescent distress. This research hypothesizes that the observed differences in adolescent distress across family structure might result from differences in the quality of parent–adolescent relationships across family structure. Analyses, using data on 1,443 youth in early and middle adolescence from the National Longitudinal Survey of Youth (NLSY), indicate that when the variations in both the quality of parent–adolescent relationships and background characteristics across family structure are controlled, the association between family structure and adolescent psychological distress is significantly reduced. Further analyses revealed that the quality of residential parent–adolescent relationships explained the most variation in adolescent psychological distress. The quality of relationships with nonresidential fathers only had a significant association with adolescent psychological distress for adolescents in blended families.