The randomized concentration-controlled trial:mathematical definitions,a dose-adjusting algorithm,and sample size efficiency

A randomized concentration-controlled trial (RCCT) (Peck 1990) is distinguished from a randomized dose-controlled trial (RDCT) by controlling the plasma concentration and allowing the dose to vary, as opposed to controlling the dose and allowing the concentration to vary. Monte Carlo studies have suggested that the RCCT is more efficient (in terms of sample size) than the more traditional dose-controlled trials. This paper presents a general mathematical defminition and investigates the properties of an RCCT. A Bayesian adjustment algorithm used in an RCCT is presented and discussed. Expressions for the sample-size efficiency of the RCCT relative to the RDCT is found for both Gaussian and Bernoulli efficacy variables. The RCCT is found to be at least as efficient in terms of sample size. The RCCT can be considerably more efficient than the RDCT.     

The use of power transformations for improved entropy estimation

A procedure for using a random sample to estimate the entropy of the sampled distribution is developed. It is based on one or two power transformations to a symmetric distribution which has the maximum entropy in a certain class. The procedure's potential for removing strong negative bias in previously proposed entropy estimators is demonstrated by the results of a Monte Carlo study.     

On A method for selecting a distributional model

A method for selecting a distributional model for a random variable, given a random sample of observations of it, is studied for various cases. The problems considered include those of choosing between the Weibull and lognormal distributions, between the lognormal and gamma distributions, and between the gamma and Weibull distributions, as well as choosing one of the three. Simulation studies were performed to estimate probabilities of correct selection for the method when it is applied to these problems     

Adaptive m estimation of symmetric distribution location

An adaptive M esitmation procedure for using a random sample to estimate the location parameter of an unknown symmetric distribution is developed. The procedure may be applied to samples from distributions with tail lenghts at least as heavy as normal distribution tails. Simulation studies demonstrate the potential of the new estimator for producing good location estimates.     

A study of the impact of environmental surroundings on personal well-being in urban China using a multi-item well-being indicator

We examine the relationship between atmospheric and water pollution, traffic congestion, access to parkland and personal well-being using a survey administered across six Chinese cities in 2007. In contrast to existing studies of well-being determinants by economists which typically employ single-item indicators, we use the Personal Well-being Index (PWI). We also employ the Job Satisfaction Survey (JSS) to measure job satisfaction, which is one of the variables for which we control when examining the relationship between environmental surroundings and personal well-being. Previous research by psychologists has shown the PWI and JSS to have good psychometric properties in western and Chinese samples. A robust finding is that in cities with higher levels of atmospheric pollution and traffic congestion, respondents report lower levels of personal well-being ceteris paribus. Specifically, we find that a one standard deviation increase in suspended particles or sulphur dioxide emissions is roughly equivalent to a 12–13% reduction in average monthly income in the six cities.     

A review of some adaptive statistical techniques

We present several methods for full, partial, and practical adaptation. Selector statistics that are measures of skewness, peakedness, and tailweight are used, primarily in estimating loca-tion in some single-sample situations. We note several practical adaptive techniques in current use, including illustrations in-volving stepwise regression, analysis of variance, ridge regres-sion, and splines. We suggest some areas in which future develop-ment of adaptive methods is needed:density estimation; M, R, and L estimation in regression; and dependent data. There is also a need to develop better selector statistics.     

Using High-Frequency Data in Dynamic Portfolio Choice

This article evaluates the economic benefit of methods that have been suggested to optimally sample (in an MSE sense) high-frequency return data for the purpose of realized variance/covariance estimation in the presence of market microstructure noise (Bandi and Russell, 2005a, 2008). We compare certainty equivalents derived from volatility-timing trading strategies relying on optimally-sampled realized variances and covariances, on realized variances and covariances obtained by sampling every 5 minutes, and on realized variances and covariances obtained by sampling every 15 minutes. In our sample, we show that a risk-averse investor who is given the option of choosing variance/covariance forecasts derived from MSE-based optimal sampling methods versus forecasts obtained from 5- and 15-minute intervals (as generally proposed in the literature) would be willing to pay up to about 80 basis points per year to achieve the level of utility that is guaranteed by optimal sampling. We find that the gains yielded by optimal sampling are economically large, statistically significant, and robust to realistic transaction costs.     

Parenting in poverty: Perspectives of high-risk parents

Parents considered high risk by child protection services commonly are striving to raise children in poverty but are identified as requiring improved parenting skills. Parent perceptions of their own needs are typically not sought or elicited. This longitudinal study of 35 parents over 18 months garnered 115 in-depth interviews focusing on parent views regarding barriers to effective parenting. Analysis indicated that parents uniformly identified poverty as the primary barrier to their capacity to provide adequate care for their children. Themes elicited indicated that financially parents were living precariously close to margins of defeat. Parents accepted personal responsibility for their economic and parental failings, equating no income with bad parenting. Depression and despair associated with poverty were acknowledged to impair parenting and increase self-doubt about parenting capacity. Experiences with social services generally led to low expectations of parenting assistance. The need for improved aid for impoverished parents is discussed.     

Ethical oxymora for risk assessment practitioners

We define working conditions faced by some practitioners of risk assessment that contradict their formal training and career expectations. Panels of expert risk scientists are used to assess the importance of these ethical oxymora. We offer recommendations aimed at helping risk scientists deal with these contradictions.

An oxymoron is a figure of speech combining contradictory ideas into a useful expression (e.g., sweet sorrow, silent thunder). In this paper we argue that some practitioners of quantitative risk assessment face working conditions that strongly contradict their professional ethos. In the first part of the paper, after briefly defining quantitative risk assessment, we describe four ethical oxymora faced by risk analysts. Second, we describe how we used panels of expert risk scientists to assess the importance of these ethical problems. We offer recommendations aimed at helping risk scientists deal with these oxymora in the last part.     

Costs of Treating Depression With Individual Versus Family Therapy

Depression is one of the most common concerns that bring clients to treatment. Although marriage and family therapy has been shown to be an effective treatment, little research exists regarding the cost‐effectiveness of related services. In this study, we examined claims data for 164,667 individuals diagnosed with depression to determine (a) differences in the cost of treating depression according to type of therapy and license type, (b) differences in recidivism rates by age, gender, type of therapy, and type of mental health professional, and (c) differences in cost‐effectiveness by therapy modality and type of professional. The results showed that services provided by marriage and family therapists resulted in the lowest recidivism rate, and family therapy services were the least expensive.