The Legalization of Abortion and Subsequent Youth Homicide: A Time Series Analysis

In this article, we examine the association between the legalization of abortion with the 1973 Roe v. Wade decision and youth homicide in the 1980s and 1990s. An interrupted time series design was used to examine the deaths of all U.S. 15- to 24-year-olds that were classified as homicides according to the International Classification of Diseases (codes E960-969) from 1970 to 1998. The legalization of abortion is associated over a decade later with a gradual reduction in the homicides of White and non-White young men. The effect on the homicides of young women is minimal. We conclude that the 1990s decline in the homicide of young men is statistically associated with the legalization of abortion. Findings are not consistent with several alternative explanations, such as changes in the crack cocaine drug market. It is almost inconceivable that in the United States of today, policies affecting the choice to have children would be justified as a means to control crime. Yet, if the legalization of abortion had this unintended effect, the full range of policy implications needs to be discussed.     

The logical reconstruction of pure exchange economics: Another alternative

Theory and Decision -     

Political confrontation over fiscal processes: The impact of the U.S. Congressional Budget Act

In July 1974 the U.S. Congressional Budget Act was signed into law. This legislation was the result of a heavily fought political confrontation between President Nixon and Congress over who controlled the Federal budget. In addition to the issue of control, the Act was prompted by dissatisfaction with the procedures used by Congress to determine Federal receipts and expenditures. The purpose of this paper is to assess the impact this legislation had on the U.S. economy in its early years.The first section of the paper sets up a simple modeling framework. The model is specified so as to illustrate how a change in the budget process resulting from the Congressional Budget Act could potentially produce changes in the level of total output. This section also explains the derivation of a tax and expenditure series used in the model's empirical testing. The second section addresses some of the theoretical issues, and presents the results of simulations based on the Chase, Wharton, and Data Resources econometric models. Broad conclusions are gathered in the final section.     

World Development and the Restructuring of the Industrial Economies

This paper reports on the joint SPM/CRANEC Catholic University of Milan symposium on “World Development and the Restructuring of Industrial Economies” held at Bellagio, Lake Como, Italy during the week of 10–15 September 1979. The symposium was organized to discuss the adjustments required by the industrialized economies when adapting to the changes inherent in present world development trends, as well as to help define national and international policy measures that might be used to facilitate the restructuring process. This report reviews the key issues, alternative strategies for restructuring, and policy measures for restructuring discussed at the symposium. It also offers some conclusions based on the results of the symposium.     

Three-stage designs for monitoring clinical trials

Optimal three-stage designs with equal sample sizes at each stage are presented and compared to fixed sample designs, fully sequential designs, designs restricted to use the fixed sample critical value at the final stage, and to modifications of other group sequential designs previously proposed in the literature. Typically, the greatest savings realized with interim analyses are obtained by the first interim look. More than 50% of the savings possible with a fully sequential design can be realized with a simple two-stage design. Three-stage designs can realize as much as 75% of the possible savings. Without much loss in efficiency, the designs can be modified so that the critical value at the final stage equals the usual fixed sample value while maintaining the overall level of significance, alleviating some potential confusion should a final stage be necessary. Some common group sequential designs, modified to allow early acceptance of the null hypothesis, are shown to be nearly optimal in some settings while performing poorly in others. An example is given to illustrate the use of several three-stage plans in the design of clinical trials.     

When Adaptations Go Awry: Functional and Dysfunctional Aspects of Social Anxiety

Adaptations are psychological and behavioral mechanisms designed through evolution to serve specific purposes ultimately related to reproductive success. Although adaptations are inherently functional, in some cases their operation can nevertheless cause personal and social dysfunction. We describe a theoretical framework for understanding, predicting, and reducing the dysfunctional consequences of psychological adaptations. We discuss three general sources of dysfunction: a) the existence of adaptive tradeoffs, b) mismatches between current environments and ancestral environments, and c) individual differences. The paper applies this framework primarily to the topic of social anxiety, a psychological phenomenon marked by concerns pertaining to social rejection and embarrassment. Although social anxiety can serve useful functions, it can also involve excessive worry, negative affect, and avoidance of social situations, leading to significant distress and social impairment. We consider sources of dysfunction in social anxiety and discuss implications for policy, including recommendations for psychological, situational, and biological interventions. We also discuss broader applications of this theoretical framework to other areas of social life.     

设计之都,一个新观点

作为世界制造中心,深圳被联合国教科文组织授予"设计之都"的称号是理所应当的,而这一殊荣又能帮助深圳提高国际知名度.对于深圳来讲,要成为世界领先的设计之都,实际上可以采取很多种途径.     

Estimating treatment effects on the marginal recurrent event mean in the presence of a terminating event

In biomedical studies where the event of interest is recurrent (e.g., hospitalization), it is often the case that the recurrent event sequence is subject to being stopped by a terminating event (e.g., death). In comparing treatment options, the marginal recurrent event mean is frequently of interest. One major complication in the recurrent/terminal event setting is that censoring times are not known for subjects observed to die, which renders standard risk set based methods of estimation inapplicable. We propose two semiparametric methods for estimating the difference or ratio of treatment-specific marginal mean numbers of events. The first method involves imputing unobserved censoring times, while the second methods uses inverse probability of censoring weighting. In each case, imbalances in the treatment-specific covariate distributions are adjusted out through inverse probability of treatment weighting. After the imputation and/or weighting, the treatment-specific means (then their difference or ratio) are estimated nonparametrically. Large-sample properties are derived for each of the proposed estimators, with finite sample properties assessed through simulation. The proposed methods are applied to kidney transplant data.