Supervision in the helping professions a practical approach

Abstract

This article is based on an ethnographic study undertaken to explore whether eight people diagnosed with terminal cancer and their families drew on aspects of their cultural identities to make sense of their journey towards death, and if so, how. Ethnographic methods were supplemented by semistructured interviews. Most participants received medical treatments until close to death and invested much effort, time, and hope in these. Consequently, they made little sense of their palliative referrals. Instead, they accommodated the biomedical cultures of treatment-oriented services, thus delaying their own and their family's preparation for death. Only three participants appeared well prepared one month prior to death. An ecological perspective helped to explain the systemic factors involved in this prioritisation. The authors make recommendations for greater involvement of social workers in palliative care, and for more attention to supporting dying people and their families to make culturally meaningful decisions in the journey toward death.     

Fast EM-type implementations for mixed effects models

The mixed effects model, in its various forms, is a common model in applied statistics. A useful strategy for fitting this model implements EM-type algorithms by treating the random effects as missing data. Such implementations, however, can be painfully slow when the variances of the random effects are small relative to the residual variance. In this paper, we apply the 'working parameter' approach to derive alternative EM-type implementations for fitting mixed effects models, which we show empirically can be hundreds of times faster than the common EM-type implementations. In our limited simulations, they also compare well with the routines in S-PLUS® and Stata® in terms of both speed and reliability. The central idea of the working parameter approach is to search for efficient data augmentation schemes for implementing the EM algorithm by minimizing the augmented information over the working parameter, and in the mixed effects setting this leads to a transfer of the mixed effects variances into the regression slope parameters. We also describe a variation for computing the restricted maximum likelihood estimate and an adaptive algorithm that takes advantage of both the standard and the alternative EM-type implementations.     

Hidden three-state survival model for bivariate longitudinal count data

Lifetime Data Analysis - A model is presented that describes bivariate longitudinal count data by conditioning on a progressive illness-death process where the two living states are latent. The...     

Weakly decomposable regularization penalties and structured sparsity

It has been shown in literature that the Lasso estimator, or ?₁‐penalized least squares estimator, enjoys good oracle properties. This paper examines which special properties of the ?₁‐penalty allow for sharp oracle results, and then extends the situation to general norm‐based penalties that satisfy a weak decomposability condition.     

On the equivalence of definitions for regular fractions of mixed-level factorial designs

The notion of regularity for fractional factorial designs was originally defined only for two-level factorial designs. Recently, rather different definitions for regular fractions of mixed-level factorial designs have been proposed by Collombier [1996. Plans d’Expérience Factoriels. Springer, Berlin], Wu and Hamada [2000. Experiments. Wiley, New York] and Pistone and Rogantin [2008. Indicator function and complex coding for mixed fractional factorial designs. J. Statist. Plann. Inference 138, 787–802]. In this paper we prove that, surprisingly, these definitions are equivalent. The proof of equivalence relies heavily on the character theory of finite Abelian groups. The group-theoretic framework provides a unified approach to deal with mixed-level factorial designs and treat symmetric factorial designs as a special case. We show how within this framework each regular fraction is uniquely characterized by a defining relation as for two-level factorial designs. The framework also allows us to extend the result that every regular fraction is an orthogonal array of a strength that is related to its resolution, as stated in Dey and Mukerjee [1999. Fractional Factorial Plans. Wiley, New York] to mixed-level factorial designs.     

A Multivariate Intervention Model for the Dutch Mint Circulation: Estimation and Monte Carlo Simulation

For each of the five Dutch coinage denominations, a transfer-function model is estimated. The output variables are monthly observations of coins in circulation. Two input variables represent transaction flows; all other inputs are step functions, representing the occurrence of interventions. Using the method of cross-correlating the residuals of the individual equations, a multivariate transfer-function model is constructed and estimated. Next Monte Carlo simulation is applied to derive expectations and variances of the yearly addition to the stock of coins until 1996. Our results enlighten on some aspects of a problem situation faced by the Dutch State Mint.     

Modeling Selectivity in Count-Data Models

This article presents a method for modeling endogenous selectivity in count data. As in the case of the switching-regression model, two regimes are distinguished with potentially different data-generating processes. The regime choice is allowed to be correlated with the observed count in each of the regimes. An estimable model is obtained by transforming the underlying processes to the bivariate normal distribution. An empirical application on trip count is provided.     

Design-based analysis of embedded experiments with applications in the Dutch Labour Force Survey

Summary.  Previous research has proposed a design-based analysis procedure for experiments that are embedded in complex sampling designs in which the ultimate sampling units of an on-going sample survey are randomized over different treatments according to completely randomized designs or randomized block designs. Design-based Wald and t -statistics are applied to test whether sample means that are observed under various survey implementations are significantly different. This approach is generalized to experimental designs in which clusters of sampling units are randomized over the different treatments. Furthermore, test statistics are derived to test differences between ratios of two sample estimates that are observed under alternative survey implementations. The methods are illustrated with a simulation study and real life applications of experiments that are embedded in the Dutch Labour Force Survey. The functionality of a software package that was developed to conduct these analyses is described.     

Risk patterns in drug safety study using relative times by accelerated failure time models when proportional hazards assumption is questionable: an illustrative case study of cancer risk of patients on glucose‐lowering therapies

Observational drug safety studies may be susceptible to confounding or protopathic bias. This bias may cause a spurious relationship between drug exposure and adverse side effect when none exists and may lead to unwarranted safety alerts. The spurious relationship may manifest itself through substantially different risk levels between exposure groups at the start of follow‐up when exposure is deemed too short to have any plausible biological effect of the drug. The restrictive proportional hazards assumption with its arbitrary choice of baseline hazard function renders the commonly used Cox proportional hazards model of limited use for revealing such potential bias. We demonstrate a fully parametric approach using accelerated failure time models with an illustrative safety study of glucose‐lowering therapies and show that its results are comparable against other methods that allow time‐varying exposure effects. Our approach includes a wide variety of models that are based on the flexible generalized gamma distribution and allows direct comparisons of estimated hazard functions following different exposure‐specific distributions of survival times. This approach lends itself to two alternative metrics, namely relative times and difference in times to event, allowing physicians more ways to communicate patient's prognosis without invoking the concept of risks, which some may find hard to grasp. In our illustrative case study, substantial differences in cancer risks at drug initiation followed by a gradual reduction towards null were found. This evidence is compatible with the presence of protopathic bias, in which undiagnosed symptoms of cancer lead to switches in diabetes medication. Copyright © 2015 John Wiley & Sons, Ltd.     

Sleep disturbances in shift-workers: A marker for maladaptation syndrome

Abstract

This study aims to examine whether the relationship between overtime and well-being is influenced by the voluntary vs. involuntary (i.e., compulsory) nature of overtime work and by the presence or absence of rewards for overtime. We also explored the prevalence of these types of overtime and how they were related to work and personal characteristics. A survey was conducted among a representative sample of Dutch full-time employees (N=1612). AN(C)OVA was used to compare rewarded and unrewarded, voluntary and involuntary overtime workers on personal and work characteristics, fatigue, and work satisfaction. Most overtime workers were rewarded (62%). About half of the sample (n=814) could be classified as either voluntary or involuntary overtime workers, or as having “mixed reasons” to work overtime. Voluntary and unrewarded overtime workers had a relatively high income and favourable job characteristics. Involuntary overtime work was associated with relatively high fatigue and low satisfaction, especially for involuntary overtime workers without rewards who can be considered a burnout risk group. Voluntary overtime workers were non-fatigued and satisfied, even without rewards. It can be concluded that control over overtime and rewards for overtime are important for well-being. Moderate overtime work may not be a problem if it is done voluntarily. Moreover, the negative effects of compulsory overtime work may be partly offset by fair compensation for the extra work.