Extension of two-sided test to multiple treatment trials

In a two-treatment trial, a two-sided test is often used to reach a conclusion, Usually we are interested in doing a two-sided test because of no prior preference between the two treatments and we want a three-decision framework. When a standard control is just as good as the new experimental treatment (which has the same toxicity and cost), then we will accept both treatments. Only when the standard control is clearly worse or better than the new experimental treatment, then we choose only one treatment. In this paper, we extend the concept of a two-sided test to the multiple treatment trial where three or more treatments are involved. The procedure turns out to be a subset selection procedure; however, the theoretical framework and performance requirement are different from the existing subset selection procedures. Two procedures (exclusion or inclusion) are developed here for the case of normal data with equal known variance. If the sample size is large, they can be applied with unknown variance and with the binomial data or survival data with random censoring.     

A New Model of Trend Inflation

This article introduces a new model of trend inflation. In contrast to many earlier approaches, which allow for trend inflation to evolve according to a random walk, ours is a bounded model which ensures that trend inflation is constrained to lie in an interval. The bounds of this interval can either be fixed or estimated from the data. Our model also allows for a time-varying degree of persistence in the transitory component of inflation. In an empirical exercise with CPI inflation, we find the model to work well, yielding more sensible measures of trend inflation and forecasting better than popular alternatives such as the unobserved components stochastic volatility model. This article has supplementary materials online.     

ANALYSIS OF DOUBLY CENSORED DATA AND THE HIV INCUBATION PERIOD DISTRIBUTION IN WESTERN AUSTRALIA

The paper analyses the distribution of times from HIV seroconversion to the first AIDS defining illness for a subcohort of the Western Australian HIV Cohort Study for whom the seroconversion date is known to fall within a calendar time window. The analysis is based on a generalised gamma model for the incubation times and a piecewise constant distribution for the conditional times of seroconversion given the seroconversion windows. This allows flexible hazard shapes and also allows comparison of goodness of fit of the gamma and Weibull distributions which are often used for modelling incubation times. Computational issues are discussed. In these data, neither age at seroconversion, nor calendar time of seroconversion, nor the identification of a seroconversion illness appears to afFect incubation distributions. The Weibull distribution appears to provide a reasonable fit. The distribution of times from seroconversion to an HIV-related death is also briefly considered.     

Advances in the surgical management of prolapse

Prolapse is an extremely common condition, for which 11% of women will have a surgical procedure at some point in their lives. The recurrence rate after most of the traditional surgical procedures is high and upto 29% of women who have had surgery for prolapse will require a further operation. In order to improve the surgical outcome, there is currently much interest in the use of grafts to augment traditional repairs and new procedures have been developed using specifically developed grafts. These have been combined with minimally invasive surgical techniques in an attempt to reduce surgical morbidity. These procedures may improve the outcome of surgery for prolapse. However, there is currently a lack of long-term data from randomized trials to demonstrate their effectiveness and safety.     

Social Harmony in Hong Kong: Level,Determinants and Policy Implications

This study aims at ascertaining how Hong Kong people perceive Hong Kong as a harmonious society. It also identifies the elements that are most conducive to social harmony in Hong Kong, so that the government could take reference when formulating new policies. 1,062 adults residents were asked to rate their perceived level of social harmony and their satisfaction with 36 items (divided into three dimensions: public governance, society, and economy, family and work) for which the research team believes would be influencing the perceived level of social harmony. Results show that the average rating of social harmony was 5.57 (out of 10), delineating a moderate level of social harmony. Subsequent multivariate factor analysis and regression analysis show that the four extracted factors (from the three dimensions) had significant impacts on the level of social harmony. These were, in order of significance: (a) public governance, (b) social solidarity and respect, (c) economy/family/work and, (d) social tolerance and progressiveness. According to the factor loadings of each significant factor, we identified four core values which we hope the government would consider when formulating new policies, as follows: (1) A Justice Government with Sincerity on Communication, (2) Mutual Support and Respect with Integrity and Dedication, (3) Dedication to One’s Job and Community by Helping the Needed and, (4) Creativity and Progressiveness with Tolerance. Implications for policy making are discussed. The study was conducted under the direction and guidance of the Fostering Social Harmony Task Force of the Hong Kong Professionals and Senior Executives Association (HKPASEA). The authors acknowledge the kind support and assistance provided by the Council Members of HKPASEA and staff members of the Centre for Corporate Governance and Financial Policy at Hong Kong Baptist University. We are also grateful to Prof. Alex Michalos and Prof. P. K. Ip for their comments and suggestions given at the International Conference on National Well-Being held in November 2006 at the National Central University, Taiwan.     

Can We Compare Life Satisfaction Between Nationalities? Evaluating Actual and Imagined Situations

Do differences in reported life satisfaction between societies reflect real differences or do they reflect cultural differences in the way people rate their experiences? Study 1 showed that imagining better or worse life situations affected student respondents’ ratings of their own life satisfaction, as predicted by range–frequency theory. Study 2 investigated how German and Polish students rated their actual life satisfaction and how satisfied they would be under three imagined scenarios. Study 3 similarly compared Danish and Hungarian students. Both studies found significant differences in the rating of the hypothetical situations, and moderate correlations between ratings of satisfaction in the hypothetical situations and reality, but in neither study were national differences in actual satisfaction predicted by differences in hypothetical satisfaction. Overall, the results suggest that national differences in rated life satisfaction are real rather than reflecting differences in how satisfaction is rated.