A note on Marshallian and von Neumann-Morgenstern utility

The curvature of a decision maker's utility function is often used to measure his risk preference. In order to comprehensively describe an individual's decision making behaviour, however, it would also seem desirable to measure the gain in utility from an increase in wealth or income before accounting for risk. If a small increase in wealth leads to a large utility gain, then it could be said that the individual's aspiration to achieve the wealth increase would be high. This aspiration, however, may be more than offset by the risk involved in obtaining this extra wealth and the individual's attitude towards risk. In the following paper it is shown how the marginal utility of Marshall can be used in a measure of aspiration with this measure then combined with the usual measure of risk preference to explain the shape of any individuals utility curve. Using these measures, a general utility curve for all income or wealth classes is postulated.The author would like to thank Professor I. Horowitz for providing the inspiration that led to his note. Any errors are the responsibility of the author.     

Exploratory Study on Drug Users’ Perspectives on Quality of Life: More than Health-Related Quality of Life?

In drug treatment outcome literature, a focus on objective and socially desirable indicators of change (e.g. no drug use) has predominated, while outcome indicators that are important for drug users themselves (e.g. quality of life, satisfaction with treatment) have largely been neglected. Nonetheless, Quality of Life (QoL) has become an important concept to evaluate effectiveness of treatment in mental health care research and disability studies. Given the almost exclusive focus on Health-related Quality of Life (HRQOL) in substance abuse research and the neglect of clients’ perspectives in this field, we explore in this study the concept of QoL as perceived by drug users. Focus group discussions (n = 9) were organised in various treatment settings and community services for drug users in the region of Ghent, Belgium to identify important dimensions of QoL and their interpretation by drug users. Data were clustered and analysed based on the theoretical framework of Robert Schalock (Quality of life. Volume 1: Conceptualization and measurement, 1996). The domains ‘personal relationships’, ‘social inclusion’ and ‘self-determination’ were discussed most frequently by the participants. They stressed the importance of a supportive social network in particular. It can be concluded that QoL is not primarily associated by drug users with health and it involves much more than the aspects typically represented in measures of HRQOL.     

Estimation of the cumulative incidence function under multiple dependent and independent censoring mechanisms

Competing risks occur in a time-to-event analysis in which a patient can experience one of several types of events. Traditional methods for handling competing risks data presuppose one censoring process, which is assumed to be independent. In a controlled clinical trial, censoring can occur for several reasons: some independent, others dependent. We propose an estimator of the cumulative incidence function in the presence of both independent and dependent censoring mechanisms. We rely on semi-parametric theory to derive an augmented inverse probability of censoring weighted (AIPCW) estimator. We demonstrate the efficiency gained when using the AIPCW estimator compared to a non-augmented estimator via simulations. We then apply our method to evaluate the safety and efficacy of three anti-HIV regimens in a randomized trial conducted by the AIDS Clinical Trial Group, ACTG A5095.     

The Gamma-count distribution in the analysis of experimental underdispersed data

Event counts are response variables with non-negative integer values representing the number of times that an event occurs within a fixed domain such as a time interval, a geographical area or a cell of a contingency table. Analysis of counts by Gaussian regression models ignores the discreteness, asymmetry and heteroscedasticity and is inefficient, providing unrealistic standard errors or possibly negative predictions of the expected number of events. The Poisson regression is the standard model for count data with underlying assumptions on the generating process which may be implausible in many applications. Statisticians have long recognized the limitation of imposing equidispersion under the Poisson regression model. A typical situation is when the conditional variance exceeds the conditional mean, in which case models allowing for overdispersion are routinely used. Less reported is the case of underdispersion with fewer modeling alternatives and assessments available in the literature. One of such alternatives, the Gamma-count model, is adopted here in the analysis of an agronomic experiment designed to investigate the effect of levels of defoliation on different phenological states upon the number of cotton bolls. Data set and code for analysis are available as online supplements. Results show improvements over the Poisson model and the semi-parametric quasi-Poisson model in capturing the observed variability in the data. Estimating rather than assuming the underlying variance process leads to important insights into the process.     

On the significance of social control: Treatment‐entry pressures,self‐choice and alcohol and drug dependence criteria one year after treatment

Storbjörk J. On the significance of social control: treatment‐entry pressures, self‐choice and alcohol and drug dependence criteria one year after treatment This article explores how self‐choice and treatment‐entry pressures are associated with one‐year treatment outcome (dependence symptoms, 0–6, 12 months) among alcohol and drug misusers, respectively. Informal pressures (from family and friends), formal pressures (related to work, healthcare, social services, social allowances, child custody) and legal pressures (related to the police, criminal justice system, compulsory treatment) were analysed. A sample (N= 1,210) representative of the addiction treatment system of Stockholm County was interviewed when starting a new treatment episode and after one year. Regression analyses indicated that self‐choice and pressures are associated with outcome among alcohol misusers but not among drug misusers when controlling for background factors and severity. Self‐choice (without pressures) correlated with a good outcome (a lower number of dependence criteria). Pressures were generally associated with poorer outcome. Alcohol misusers who had experienced threats regarding child custody did better in comparison with those not experiencing such pressure. The difference in results by drug type and implications were discussed.     

Using a “child's‐eye view” of social success to understand the importance of school readiness at the transition to formal schooling

Recent research into school readiness has highlighted the importance of not only children's cognitive and socio‐emotional skills, but also the degree to which they have family support in the home. The current study examines the association between social success upon school entry and teacher‐ratings of school readiness as assessed by the Brief Early Skills and Support Index (BESSI), controlling for language ability. Importantly, social success was assessed using a “child's‐eye view” with peer‐reported assessments of both social preference and reciprocated friendships. A total of 244 children (131 boys, M_age = 61 months, SD = 4.78 months) in their first year of formal schooling participated. Child school readiness was found to be important for social preference, with the association being more marked for boys versus girls. Family support was the only independent predictor of children's reciprocated friendships. The use of the BESSI, with its broad scope compared to other measures of school readiness, highlights the importance of focusing both on a child's cognitive and socio‐emotional skills at school entry and their family support when exploring the association of school readiness to children's social success at the transition to formal schooling.     

‘Speak roughly to your little boy’? Sex Differences in the Relations Between Parenting and Preschoolers’ Understanding of Mind

The present study explores relations between young children's understanding of mind and parental emotional expression and disciplinary style, along with gender differences in these relations. Participants were recruited from a study of 125 same-sex twin-pairs (58% female; group mean age 5 43 months, SD 5 1 month). Each child received a comprehensive set of theory-of-mind tasks, and was filmed at home for 20 minutes in dyadic interactions with the primary caregiver, who was also interviewed about disciplinary strategies. Ratings of discipline and positive and negative parental affect and control were made from direct observation, from the interview, and from the videoed interactions. Strong correlations were found between family SES, parenting measures, and child verbal IQ and theory-of-mind score. However, regression analyses showed that parental behaviours were significant predictors of children's theory-of-mind performance, even when sex, verbal IQ and family SES were taken into account. Sex differences in these relations were also identified; parental affect was especially salient for understanding of mind in girls, while discipline was more salient for boys. Taken together, these findings highlight the importance of individual differences in the proximal processes associated with early understanding of mind, and suggest that development in mental-state awareness is associated with distinct aspects of parenting for girls and boys.