Extracting a revised labor supply theory from Becker's model of the household

Conflicting assumptions about labor supply behavior lie at the nexus of ideological and theoretical debates regarding the reality of involuntary unemployment, the efficacy of Keynesian macro-policy, and the appropriate nature of welfare policy. This can in part be attributed to the fact that orthodox theory is effectively predicated upon describing the behavior of individuals whose level of affluence enables them to voluntarily withhold their labor from the market. Ironically, a means of resolution appears if we extend Gary Becker's utility producing model of the household to recognize two latent behavioral concerns: (1) the ‘need’ of households for money income in order to produce utility, and (2) the presence of work activity in the home. The resulting generalized labor supply model extends Becker's analysis to explicitly encompass both the behavior of the affluent, and the behavior of the poor who need to work in order to sustain their existence.     

Prediction based classification for longitudinal biomarkers

Assessment of circulating CD4 count change over time in HIV-infected subjects on antiretroviral therapy (ART) is a central component of disease monitoring. The increasing number of HIV-infected subjects starting therapy and the limited capacity to support CD4 count testing within resource-limited settings have fueled interest in identifying correlates of CD4 count change such as total lymphocyte count, among others. The application of modeling techniques will be essential to this endeavor due to the typically non-linear CD4 trajectory over time and the multiple input variables necessary for capturing CD4 variability. We propose a prediction based classification approach that involves first stage modeling and subsequent classification based on clinically meaningful thresholds. This approach draws on existing analytical methods described in the receiver operating characteristic curve literature while presenting an extension for handling a continuous outcome. Application of this method to an independent test sample results in greater than 98% positive predictive value for CD4 count change. The prediction algorithm is derived based on a cohort of n = 270 HIV-1 infected individuals from the Royal Free Hospital, London who were followed for up to three years from initiation of ART. A test sample comprised of n = 72 individuals from Philadelphia and followed for a similar length of time is used for validation. Results suggest that this approach may be a useful tool for prioritizing limited laboratory resources for CD4 testing after subjects start antiretroviral therapy.     

Multiple Co-occurring Behaviours among Gamblers in Treatment: Implications and Assessment

A substantial portion of gamblers in treatment may have co-occurring mental health disorders including substance use disorders, especially alcohol dependency, personality disorders, affective disorders, anxiety disorders and impulse control disorders. Co-occurring mental health disorders affect treatment seeking, the treatment process and its outcome, quality of life and functioning in many mental health disorders. Participants in this study were 78 adults enrolled in state-supported out-patient services for pathological gambling and current Gamblers Anonymous attendees. The majority of participants (76.6%) had co-occurring behaviours; 55.8% had multiple co-occurring behaviours. Participants with multiple co-occurring behaviours were more likely to report that a co-occurring behaviour increased the severity of their gambling symptoms. A dose/response relationship between number of co-occurring behaviours and severity of gambling problems was found. Co-occurring behaviours can interact with gambling behaviour. Brief, validated screening instruments are available for screening and diagnosing co-occurring behaviours among gamblers presenting for treatment.     

Automatic locally adaptive smoothing for tree-based set estimation

Tree-based methods similar to CART have recently been utilized for problems in which the main goal is to estimate some set of interest. It is often the case that the boundary of the true set is smooth in some sense, however tree-based estimates will not be smooth, as they will be a union of ‘boxes’. We propose a general methodology for smoothing such sets that allows for varying levels of smoothness on the boundary automatically. The method is similar to the idea underlying support vector machines, which is applying a computationally simple technique to data after a non-linear mapping to produce smooth estimates in the original space. In particular, we consider the problem of level-set estimation for regression functions and the dyadic tree-based method of Willett and Nowak [Minimax optimal level-set estimation, IEEE Trans. Image Process. 16 (2007), pp. 2965–2979].     

Reflections on Changes in the Library and Serials Literature

Abstract

Johnson describes changes in library journal literature topics over the past one hundred years, with a focus on the period between her first Balance Point column in 2003 and this one, her last. She reminisces on her experience as a Balance Point column editor.     

An examination of sexual strategies used by urban southern and rural Midwestern university women

The purposes of this study were (a) to determine whether women's use of persuasion, non‐physical coercion, and physical force strategies to obtain sex from a man varied between U.S. women from an urban Southern and rural Midwestern university and (b) to determine if sexual behavior history and early courtship behavior affected the use of these strategies (or not using any strategy). Women from the Midwest and the South did not differ in their use of sexual strategies. There were, however, other variables that accounted for differences in women's use of sexual strategies. Women who used persuasion strategies had fewer lifetime sexual partners than women who used any other strategy. Women who used physical force strategies reported a lower age at first intercourse and more early courtship behaviors than all others. Overall, the results indicated that sexual strategies are related to sexual behavior history and early courtship behaviors rather than cultural setting or demographics.