Optimal significance levels of prior tests in the presence of multicollinearity

A common approach in estimation is to use the same data to select a model by prior testing as well as to estimate the parameters in the final selection. A problem which arises is that the quadratic risk of such an estimator depends on the significance level of the prior test. The traditional 5 percent level can lead to unacceptably large quadratic risk particularly if the data exhibits high multicollinearity. Two criteria are considered for limiting the quadratic risk. It is shown that these criteria lead to easily calculated and quite accurate rules for determining the critical value of the prior test.     

Location, Location, Location: Does Place of Work Really Matter?

This paper examines the work attitudes of home- and office-based workers. A review of the existing literature finds both pessimistic and optimistic accounts of the impact of homeworking on employee attitudes and behaviours. Drawing on a survey of 749 managerial and professional employees in knowledge-intensive industries, the study finds more support for the optimistic perspective. The findings suggest that homeworking is positively associated with employee well-being and a more balanced work–home relationship. There is no evidence that organizational citizenship behaviours are reduced by homeworking but there is some support for homeworking undermining employees' perception of the organization as supporting their careers and personal development.     

A robust regression methodology via M-estimation

A robust regression methodology is proposed via M-estimation. The approach adapts to the tail behavior and skewness of the distribution of the random error terms, providing for a reliable analysis under a broad class of distributions. This is accomplished by allowing the objective function, used to determine the regression parameter estimates, to be selected in a data driven manner. The asymptotic properties of the proposed estimator are established and a numerical algorithm is provided to implement the methodology. The finite sample performance of the proposed approach is exhibited through simulation and the approach was used to analyze two motivating datasets.     

Optimal composite scores for longitudinal clinical trials under the linear mixed effects model

Clinical trials of chronic, progressive conditions use rate of change on continuous measures as the primary outcome measure, with slowing of progression on the measure as evidence of clinical efficacy. For clinical trials with a single prespecified primary endpoint, it is important to choose an endpoint with the best signal‐to‐noise properties to optimize statistical power to detect a treatment effect. Composite endpoints composed of a linear weighted average of candidate outcome measures have also been proposed. Composites constructed as simple sums or averages of component tests, as well as composites constructed using weights derived from more sophisticated approaches, can be suboptimal, in some cases performing worse than individual outcome measures. We extend recent research on the construction of efficient linearly weighted composites by establishing the often overlooked connection between trial design and composite performance under linear mixed effects model assumptions and derive a formula for calculating composites that are optimal for longitudinal clinical trials of known, arbitrary design. Using data from a completed trial, we provide example calculations showing that the optimally weighted linear combination of scales can improve the efficiency of trials by almost 20% compared with the most efficient of the individual component scales. Additional simulations and analytical results demonstrate the potential losses in efficiency that can result from alternative published approaches to composite construction and explore the impact of weight estimation on composite performance. Copyright © 2016. The Authors. Pharmaceutical Statistics Published by John Wiley & Sons Ltd.     

Saying Meritocracy and Doing Privilege

This article describes the relationship between saying and doing. It argues that focusing on the discrepancy between participants’ accounts and their actions is one of the greatest analytical strengths of ethnography. We make this case by drawing upon an ethnography of an elite boarding school. We also reflect on the way that two ethnographers worked together to better understand the social significance of accounts that are incongruent with situated behavior. We conclude by arguing that qualitative researchers must be more sensitive to the different kinds of claims that can be made with interview versus observational data.     

Reconceptualizing Women's and Men's Undeclared Work: Some Results from a European Union Survey

Recognizing that the current conceptualizations of men's and women's undeclared work derive almost entirely from a limited range of small‐scale studies of specific localities, sectors and occupations, this article begins to resolve this dearth of evidence by reporting the findings of an extensive cross‐national survey of undeclared work conducted in 2007 across 27 European Union (EU) nations. The outcome is fresh and extensive EU‐wide evidence that extends existing conceptualizations of the gender differences in terms of participation, sector, contract type and pay. However, the recognition that undeclared work is conducted for closer social relations and sometimes for motives other than financial gain, is shown to apply not only to women, as previously contended, but to men as well and to constitute most of the undeclared work in the EU. The result is a call for a fundamental reconceptualization of the nature of undeclared work that recognizes the heterogeneous work relations involved.     

Themes on hope and living with a life-threatening illness

Abstract

This article presents a discussion of themes relating to hope and living with a life-threatening illness. Six interwoven themes are identified: configuring goals, enhancing health and survival, getting empowered, relating to fear, orientating to time, and giving life meaning. These themes offer a repertoire of hope and challenge us to develop skills across shifting paradigms.