An Estimator for Some Binary-Outcome Selection Models Without Exclusion Restrictions

This article provides a new maximum-likelihood estimator forselection models with dichotomous dependent variables when identicalfactors affect the selection equation and the equation of interest.Such situations arise naturally in game-theoretic models whereselection is typically nonrandom and identical explanatory variablesinfluence all decisions under investigation. When identicalexplanatory variables influence selection and a subsequent outcomeof interest, the commonly used Heckman-type estimators identifyfrom distributional assumptions about the residuals alone. Whenits own identifying assumption is reasonable, the new estimatorallows the researcher to avoid the painful choice between identifyingfrom distributional assumptions alone and adding a theoreticallyunjustified variable to the selection equation in a mistakenattempt to "boost" identification. The article uses Monte Carlomethods to compare the small-sample properties of the estimatorwith those of the Heckman-type estimator and ordinary probit.     

Contraceptive behavior in adolescence: A decision-making perspective

The contraceptive behavior of adolescent girls was viewed from a decision-making perspective. A semistructured interview protocol was used in interviewing 120 girls aged 12–19 in three clinics (Teen Family Planning, Prenatal, Pediatric Acute Care) at Michael Reese Hospital and Medical Center on (1) demographic in formation; (2) sexual and obstetric history; (3) contraceptive and sexual knowledge, attitudes, and practices; (4) environmental pressures; (5) personality factors; and (6) decision-making style. We found that the girls were generally poor contraceptors. They viewed the costs of contraception (in terms of safety) to be high; and they positively valued physical intimacy, opportunities for which come up unexpectedly and sporadically. These factors, along with their ambivalent views toward pregnancy and childbearing seemed to encourage their risk-taking behavior. Once pregnancy occurred, it was carried to term because of the strong internal and external pressures they felt to have and keep the baby. The peer-led intervention program that we are developing based on the survey findings will focus on (1) the teenagers' lack of accurate and complete knowledge about birth control and conception, (2) their limited sense of options concerning birth control and pregnancy outcomes, and (3) their poor understanding of and lack of insight into what motivates their behavior.This study is part of the investigation being conducted by the YADMAC (Young Adult and Adolescent Decision Making About Contraception) Project at Michael Reese Hospital and Medical Center, 2959 South Cottage Grove, Chicago, Illinois 60616. The authors are all members of the YADMAC research team.Received Ph.D. from the University of Chicago. Current interests are human sexuality and reproductive behavior. Currently at Department of Psychology, St. Xavier College.Received M.D. from the University of Michigan. Current interests are liaison child psychiatry and adolescent sexuality.Received Ph.D. from the University of Chicago. Current interests are early adolescent development issues.Current interests are puberty and sex differences.B. A. candidate in social work, Roosevelt University. Current interests are adolescent sexuality and contraceptive behavior.     

Thinking like a lawyer/acting like a professional: communities of practice as a means of challenging orthodox legal education

Increasingly, there is pressure upon law schools, in Australia and elsewhere, to impress upon students the significance of the ethical and professional obligations of legal practice. The recent Carnegie Report explicitly looked to law schools “to initiate novice practitioners to think, to perform, and to conduct themselves (that is, to act morally and ethically) like professionals”. Many law students, however, have little appreciation of legal ethics and any concept they may have of professionalism tends to be envisaged as applying only after graduation. In this paper, we explore the idea of a “community of practice”. Lave and Wenger, who coined the phrase, contend that “learning is conceived as a trajectory in which learners move from legitimate peripheral participant to core participant of the community of practice”. We will argue that law students should appreciate that they are entering the legal profession's community of practice and that all aspects of their conduct relevant to professionalism – not only academic integrity, but matters such as time management, teamwork, relationships with peers and staff – relate to this transition into a legal professional community. Such an approach may not only serve to impress upon students the significance of “professionalism” and ethics, but inculcate in them a sense of belonging to a professional community.