Three estimators for the poisson regression model with measurement errors

We consider two consistent estimators for the parameters of the linear predictor in the Poisson regression model, where the covariate is measured with errors. The measurement errors are assumed to be normally distributed with known error variance σ _u ² . The SQS estimator, based on a conditional mean-variance model, takes the distribution of the latent covariate into account, and this is here assumed to be a normal distribution. The CS estimator, based on a corrected score function, does not use the distribution of the latent covariate. Nevertheless, for small σ _u ² , both estimators have identical asymptotic covariance matrices up to the order of σ _u ² . We also compare the consistent estimators to the naive estimator, which is based on replacing the latent covariate with its (erroneously) measured counterpart. The naive estimator is biased, but has a smaller covariance matrix than the consistent estimators (at least up to the order of σ _u ² ).     

Ready or not: assessing youths' preparedness for independent living

This article discusses the utility of the Ansell-Casey Life Skills Assessment (ACLSA) in assessing life skills necessary for living successfully in the community upon emancipation from out-of-home care. ACLSA, completed by youths and their caregivers, identifies skills that have been mastered and those yet to be learned. Assessment information can be used for goal setting, strength identification, and relationship building, as well as to direct program planning and training in self-sufficiency services.     

Fertility history, health, and health changes in later life: a panel study of British women and men born 1923-49

We investigated associations between later-life health and fertility history for women and men, using the British Household Panel Survey. We modelled health and its rate of change jointly with sample retention over an 11-year period. For women, childlessness is associated with limitation of activity for health reasons and faster acquisition of the limitation. High parity (four or more children) is associated with poorer health for both women and men. For the parous, this association is also found when age at first birth is controlled. Early parenthood is associated with poorer health. For parents of two or more children, a birth interval of less than 18 months is associated with having a health limitation and an accelerated rate of acquiring it. We conclude that biosocial pathways link parenthood careers and the later-life health of both women and men, and that implications of closely spaced births for parents merit further attention.     

Level and change of group-focused enmity in Germany: unconditional and conditional latent growth curve models with four panel waves

In this study, we investigate and explain the level and change of six elements of group-focused enmity (GFE; see Zick et al. in J. Soc. Issues 64(2):363–383, 2008) in Germany between 2002 and 2006: racism, xenophobia, anti-Semitism, homophobia, exclusion of homeless people and support for rights of the established. For the data analysis, a representative 4-year panel study of the adult non-immigrant German population collected during the years 2002–2006 is used, and the development of each GFE component is tested by using an unconditional second-order latent growth curve model (LGM) (with full information maximum likelihood, FIML). We find that the level of 5 of the 6 components (racism, xenophobia, anti-Semitism, homophobia, exclusion of homeless people) displays an increase at the beginning of the observed period followed by a decrease. However, the sixth aspect, rights of the established, displays a continuous linear increase over time. The different developmental pattern stands in contrast to Allport’s (The nature of prejudice. Perseus Books, Cambridge, 1954) hypothesis for the strong link between the components and their development over time. We try to explain this different developmental pattern by several sociodemographic characteristics. This is performed by using a conditional second-order latent growth curve model.     

Exact percentage points for the Kolmogorov test on truncated versions of known continuous distributions with unknown truncation parameters

In this paper we deal with Kolmogorov-Smirnov testson uniformity with completely or partly unknown limits. Tables of exact percentage points are presented or referred using the wellknown determinant formula given by Steck (1971). It is shown that these tables also give the percentage points for the analogous statistics of the test on truncated versions of known continuous distributions with completely or partly unknown truncation limits. We will give some examples of these applications. Among these are the tests on exponentiality and on Pareto distribution with known shape parameter and unknown lower terminal.     

DESIGNING HIGH-CONTACT SERVICE SYSTEMS: APPLICATION TO BRANCHES OF A SAVINGS AND LOAN*

The customer-contact model represents one of the few conceptually based approaches for designing service systems. This paper develops that concept further for high-contact systems, relative to efficiency and effectiveness notions. Four design features (contact technologies, contact training, data bases, and contact roles) are developed and a simple design methodology (built around the four design features) is presented. A demonstration of the design methodology is provided through its applications to branches of a savings and loan. Areas for additional theoretical and practical refinement of the model and the desirability of multidisciplinary research are discussed.     

An evaluation of common methods for dichotomization of continuous variables to discriminate disease status

Dichotomization of continuous variables to discriminate a dichotomous outcome is often useful in statistical applications. If a true threshold for a continuous variable exists, the challenge is identifying it. This paper examines common methods for dichotomization to identify which ones recover a true threshold. We provide mathematical and numeric proofs demonstrating that maximizing the odds ratio, Youden’s statistic, Gini Index, chi-square statistic, relative risk and kappa statistic all theoretically recover a true threshold. A simulation study evaluating the ability of these statistics to recover a threshold when sampling from a population indicates that maximizing the chi-square statistic and Gini Index have the smallest bias and variability when the probability of being larger than the threshold is small while maximizing Kappa or Youden’s statistics is best when this probability is larger. Maximizing odds ratio is the most variable and biased of the methods.     

Modeling Transition Rates Using Panel Current-Status Data: How Serious is the Bias?

Studies of disability dynamics and active life expectancy often rely on transition rates or probabilities that are estimated using panel survey data in which respondents report on current health or functional status. If respondents are contacted at intervals of one or two years, then relatively short periods of disability or recovery between surveys may be missed. Much published research that uses such data assumes that there are no unrecorded transitions, applying event-history techniques to estimate transition rates. In recent years, a different approach based on embedded Markov chains has received growing use. We assessed the performance of both approaches, using as a criterion their ability to reproduce the parameters of a “true” model based on panel data collected at one-month intervals. Neither of the widely used approaches performs particularly well, and neither is uniformly superior to the other.     

Measuring Attitudes Toward Empirically Supported Treatment in Real-World Addiction Services

Mental health workers with favorable attitudes toward empirically supported treatments (ESTs) are more likely to break through implementation barriers. The Evidence-Based Practice Attitude Scale has been shown to be reliable for mental health workers, but it has not been validated with addiction workers. This study investigates the use of the scale with a convenience sample of addiction workers from 4 agencies in 1 city. Results show that compared to mental health providers, addiction workers were more likely to view ESTs favorably if they were mandated and intuitively appealing. They also tended to rely more heavily on practical experience in forming attitudes toward treatment options. These results might help addiction agencies understand which types of workers are more likely to implement ESTs and inform effective engagement approaches specific to addiction workers.