Higher Order Properties of Gmm and Generalized Empirical Likelihood Estimators

In an effort to improve the small sample properties of generalized method of moments (GMM) estimators, a number of alternative estimators have been suggested. These include empirical likelihood (EL), continuous updating, and exponential tilting estimators. We show that these estimators share a common structure, being members of a class of generalized empirical likelihood (GEL) estimators. We use this structure to compare their higher order asymptotic properties. We find that GEL has no asymptotic bias due to correlation of the moment functions with their Jacobian, eliminating an important source of bias for GMM in models with endogeneity. We also find that EL has no asymptotic bias from estimating the optimal weight matrix, eliminating a further important source of bias for GMM in panel data models. We give bias corrected GMM and GEL estimators. We also show that bias corrected EL inherits the higher order property of maximum likelihood, that it is higher order asymptotically efficient relative to the other bias corrected estimators.     

Efficient Semiparametric Estimation via Moment Restrictions

Conditional moment restrictions can be combined through GMM estimation to construct more efficient semiparametric estimators. This paper is about attainable efficiency for such estimators. We define and use a moment tangent set, the directions of departure from the truth allowed by the moments, to characterize when the semiparametric efficiency bound can be attained. The efficiency condition is that the moment tangent set equals the model tangent set. We apply these results to transformed, censored, and truncated regression models, e.g., finding that the conditional moment restrictions from Powell's (1986) censored regression quantile estimators can be combined to approximate efficiency when the disturbance is independent of regressors.     

What does youth-led participatory budgeting reveal about youth priorities? Ideas,votes, and decisions

Youth involvement in community decision-making is considered a core principle of both youth advocacy and progressive governance. Yet, in many communities formal roles for youth remain limited. This paper presents data from a youth-led participatory budgeting process in Boston, Massachusetts (US). The City of Boston has institutionalized a formal process through which numerous youth can contribute ideas and vote on capital projects to receive city funding. A smaller group of youth are engaged in even greater depth. They are trained and work to facilitate submission of ideas, turn ideas into proposals, and encourage youth voting. We use data to identify concerns expressed by youth, their ideas for solutions, and the movement from ideas to funded projects. Implications for further development of participatory budgeting as a mechanism for youth civic engagement are discussed.     

Cultivating Positive LGBTQA Identities: An Intervention Study with College Students

A brief intervention exercise focusing on positive experiences of lesbian, gay, bisexual, transgender, and queer or questioning young adults and their young adult allies (LGBTQA) was hypothesized to increase positive LGBTQA identity, collective self-esteem, and individual self-esteem. Participants (N = 52) completed pretest, listened to a presentation on positive LGBTQA identities, and wrote personal narratives related to their own positive identity experiences. They then completed posttest and one-month follow-up surveys. Findings indicated that scores on all three outcomes significantly increased between the pre- and posttest but returned to baseline levels when reassessed one month later. Future research should explore ways to enhance the long-term impact of exposure to positive identity interventions on LGBTQA well-being in the current heteronormative cultural environment.     

The reliability of environmental measures of the college alcohol environment

Much of what we know about students' drinking patterns and problems related to alcohol use is based on survey research. Although local and national survey data are important to alcohol-prevention projects, they do not sufficiently capture the complexity of the alcohol environment. Environmental prevention approaches to alcohol-related problems have been shown to be effective in community settings and researchers have begun to study and adapt such approaches for use on college campuses. Many environmental approaches require systematic scanning of the campus alcohol environment. This study assessed the inter-rater reliability of two environmental scanning tools (a newspaper content analysis form and a bulletin analysis form) designed to identify alcohol-related advertisements targeting college students. Inter-rater reliability for these forms varied across different rating categories and ranged from poor to excellent. Suggestions for future research are addressed.     

Brave New Worlds: Philosophy,Politics, and Science in Human Biotechnology

Advances in biotechnology have important applications to the core demographic concerns of human reproduction and longevity, raising a number of difficult ethical issues. In the debate over those issues, however, the voices of demographers and other social scientists are nearly silent. In the United States the dominant bioethical arguments currently heard come from a conservative political and ideological position, represented, for example, by the President's Council on Bioethics and in particular by its chairman, Leon Kass. A critical discussion of Kass's writings identifies the philosophical roots of that position and highlights its logic and limits. Kass's specific arguments on cloning can be challenged by applying them to an earlier and revolutionary technology, birth control; his views on death and dying would argue for curtailing investment in life‐extending technology. Conservatism of this kind ignores social science perspectives and forecloses opportunities for social change.     

Population planning in Asia in the 1970s

Summary To what extent is family planning integrated with broader population planning in the countries of East Asia and South Asia? To what degree do these countries combine population planning with economic and social planning in their development plans? An attempt to answer these questions suggests that, despite variability from country to country in development goals and policy implementation, family planning has been largely separated from economic planning, and birth control programmes have often been substituted for intermediate and long-range population planning. Demographic factors have been treated as exogenous variables rather than as integral parts of social-economic-demographic plans. Such comprehensive planning is difficult for both technical and political reasons, but in any case is unlikely to be achieved so long as family planning and population planning continue to be confused.     

Electrophysiological Brain Responses of Six‐Month‐Old Low Risk Premature Infants

This study sought to examine the electrophysiological correlates of visual perceptual priming in a sample of low risk preterm infants. We compared the ERP data of 20 healthy preterm infants at the age of 6 months (corrected age: 4 months) to those of 20 six‐month‐old and 20 four‐month‐old full term infants. The comparison groups represented the preterm infants' chronological and corrected ages respectively. The results showed that the brain responses of the preterm infants at the age of 6 months, specifically the topography and the latency of the Nc component, are more similar to those of their corrected age peers than to those of the chronological age controls.