Tree-structured analysis of treatment effects with large observational data

Treatment effect in an observational study of relatively large scale can be described as a mixture of effects among subgroups. In particular, analysis for estimating the treatment effect at the level of an entire sample potentially involves not only differential effects across subgroups of the entire study cohort, but also differential propensities – probabilities of receiving treatment given study subjects’ pretreatment history. Such complex heterogeneity is of great research interest because the analysis of treatment effects can substantially depend on the hidden data structure for effect sizes and propensities. To uncover the unseen data structure, we propose a likelihood-based regression tree method which we call marginal tree (MT). The MT method is aimed at a simultaneous assessment of differential effects and propensity scores so that both become homogeneous within each terminal node of the resultant tree structure. We assess simulation performances of the MT method by comparing it with other existing tree methods and illustrate its use with a simulated data set, where the objective is to assess the effects of dieting behavior on its subsequent emotional distress among adolescent girls.     

Comparison of three-dimensional profiles over time

In this paper, we describe an analysis for data collected on a three-dimensional spatial lattice with treatments applied at the horizontal lattice points. Spatial correlation is accounted for using a conditional autoregressive model. Observations are defined as neighbours only if they are at the same depth. This allows the corresponding variance components to vary by depth. We use the Markov chain Monte Carlo method with block updating, together with Krylov subspace methods, for efficient estimation of the model. The method is applicable to both regular and irregular horizontal lattices and hence to data collected at any set of horizontal sites for a set of depths or heights, for example, water column or soil profile data. The model for the three-dimensional data is applied to agricultural trial data for five separate days taken roughly six months apart in order to determine possible relationships over time. The purpose of the trial is to determine a form of cropping that leads to less moist soils in the root zone and beyond. We estimate moisture for each date, depth and treatment accounting for spatial correlation and determine relationships of these and other parameters over time.     

Embracing risk as a core competence: The case of CEMEX

In this paper we argue that risk management can be an important source of competitive advantage for firms. For this to happen, managers must overcome four deep-seated notions about the management of risk: the myopic conception that risk is a collection of unconnected threats to the survival of a firm, the belief that risk management is largely a financial activity, the idea that risk management is solely a top management team task, and a blind faith that CEOs can continuously anticipate the risks that firms must address on an ongoing basis. Challenging these four misconceptions reveals that risk management can be an activity that is value creating, not just value preserving. Indeed, rather than indiscriminately shedding all types of risks, companies can develop new sources of competitive advantage by embracing those risks that they are relatively better at managing than their rivals. We illustrate our arguments by analyzing the risk management practices at CEMEX, the Mexican cement manufacturer.     

Differing Domains of Actual Sibling Conflict Discussions and Associations with Conflict Styles and Relationship Quality

Four types of sibling conflict were identified in actual adolescent sibling discussions: equality and fairness, invasion of the personal domain, intrinsic harm, and relationships. Older [M = 14.97, standard deviation (SD) = 1.69 years] and younger siblings (M = 12.20, SD = 1.90 years) from 144 dyads discussed conflicts during a semi‐structured conflict task. Trained observers coded the topics discussed, and separate observers rated their conflict styles, whereas siblings rated their relationship quality. The proportion of conflicts of each domain differed by dyadic gender composition. Equality and fairness conflicts (and invasion of the personal domain conflicts for sister–sister pairs) were discussed the most frequently whereas intrinsic harm conflicts were associated with destructive conflict styles. Siblings' discussions of conflicts involving intrinsic harm were associated with older siblings' reports of negative relationship quality. The associations between these conflict topics and negative relationship quality were mediated by the siblings discussing the conflicts in destructive ways.     

Sexual orientation of human offspring may be altered by severe maternal stress during pregnancy

To test the hypotheses that maternal stress during pregnancy may alter the sexual orientation of offspring, 285 women with offspring 19 years of age and older provided retrospective accounts of stressful experiences they had, beginning 12 months prior to pregnancy up to the point of giving birth, and indicated how severe they recalled each event being. When weighted according to severity, stressful experiences helped to predict sexual orientation of male offspring. While most of the variance in sexual orientation remained unexplained, the data suggest that the most critical time in gestation for influencing human sexual orientation of male offspring is during the second trimester, although the first and possibly the third trimesters may be of secondary importance. For female offspring, no significant relationships between maternal stress and sexual orientation were found, although mothers of lesbians did report slightly higher average levels of stress throughout gestation than mothers of female heterosexuals.     

Sociology in the high school: Perceptions of those who teach it

The following research note reports two major findings of a more detailed study of the opinions, training, and practices of teachers of high school sociology in Texas. Two major findings of interest to the discipline emerge from the research: (1) high school teachers are only marginally prepared in the field of sociology itself; (2) teachers generally give sociology's reputation as a discipline a favorable rating, while at the same time showing concerns about whether or not they would recommend sociology as a college major. The implications of teacher attitudes and training for the discipline are explored.     

Did the Military Interventions in the Mexican Drug War Increase Violence?

We analyze publicly available data to estimate the causal effects of military interventions on the homicide rates in certain problematic regions in Mexico. We use the Rubin causal model to compare the post-intervention homicide rate in each intervened region to the hypothetical homicide rate for that same year had the military intervention not taken place. Because the effect of a military intervention is not confined to the municipality subject to the intervention, a nonstandard definition of units is necessary to estimate the causal effect of the intervention under the standard no-interference assumption of stable-unit treatment value assumption (SUTVA). Donor pools are created for each missing potential outcome under no intervention, thereby allowing for the estimation of unit-level causal effects. A multiple imputation approach accounts for uncertainty about the missing potential outcomes.     

Diversity training pitfalls and possibilities: An exploration of small and mid-size US organizations

Abstract

This qualitative, exploratory study examines the development and implementation of diversity training in small and mid-size organizations in a Midwestern region of the United States. The results are contrasted with diversity best practices and found lacking in key elements identified as most likely to yield success. Specifically, the organizations in this study did not provide training beyond awareness level, failed to conduct front-end needs assessment, provided little if any in-depth evaluation of diversity training and showed varying support for diversity endeavors from the leadership and through connecting diversity training with other systemic initiatives. The article concludes with recommendations for additional exploration of adapting effective diversity training practices to minimize pitfalls and maximize possibilities in small and mid-size systems.     

Fishermens blues: Factors related to accidents and safety among Newfoundland fishermen

Abstract

The fisheries is one of the most dangerous industries in Canada. Possible contributory causes of the high rate of injuries are a fatalistic attitude to accidents and safety, and a high level of anxiety and worry among fishermen. These characteristics would be expected to lead to less attention to safety procedures and a consequent greater risk of accidents. The purpose of this study was to explore fishermen's levels of fatalism and anxiety; to consider the relationship of these factors to the frequency of accidents and extent of safety precautions; and to explore fishermen's explanations of and suggested solutions to the high rate of injuries at sea. The study was conducted among a sample of inshore fishermen who fished in the waters around Newfoundland. Fifty-five fishermen completed a questionnaire that requested basic demographic details, information on injuries obtained, safety precautions taken, perceived locus of control over accidents, anxiety, worries and explanations for accidents and possible measures to reduce them. Analysis of their replies revealed that the fishermen reported a high level of anxiety and that those who reported most anxiety reported more injuries and fewer safety precautions.