A Simulation Comparison of Approximate Tests for Fixed Effects in Random Coefficients Growth Curve Models

Often, the response variables on sampling units are observed repeatedly over time. The sampling units may come from different populations, such as treatment groups. This setting is routinely modeled by a random coefficients growth curve model, and the techniques of general linear mixed models are applied to address the primary research aim. An alternative approach is to reduce each subject’s data to summary measures, such as within-subject averages or regression coefficients. One may then test for equality of means of the summary measures (or functions of them) among treatment groups. Here, we compare by simulation the performance characteristics of three approximate tests based on summary measures and one based on the full data, focusing mainly on accuracy of p-values. We find that performances of these procedures can be quite different for small samples in several different configurations of parameter values. The summary-measures approach performed at least as well as the full-data mixed models approach.     

Reports of Conferences,Institutes, and Seminars

Abstract

This column covers several conference sessions from the 14th annual Electronic Resources & Libraries Conference, providing guidance on how to navigate ebook duplication, improving documentation and workflows, implementing OpenAthens, and experiences with Project SILLVR (Streaming Interlibrary Loan Video Resources)and knowledge bases and related tools (KBART) automation. There is also a report from IFLA’s SIG Library Publishing Mid-Term meeting, which was an ideological meeting in nature, discussing community building, resource sharing, and status updates. A report from the 2018 Charleston Conference is also included.     

Reordering Spatial and Social Relations: A Case Study of Professional and Managerial Flexworkers

Research on flexible work practices has focused primarily on social relationships, individual identity, work/work–life balance experience and performance. This paper aims to add another dimension by focusing on space and, specifically, the performance of space by professional flexworkers as they reorder their home and work lives through the process of becoming flexworkers. Drawing on Law's ‘modes of ordering’ and Latourian actor network theory, as well as on Beyes and Steyaert's recent contribution on ‘performing space’, the paper considers how flexworkers themselves reorganize space(s) as an ongoing accomplishment. The purpose and contribution is to offer an alternative to the view that the home and work are rigid containers fixed in social structure, to one that views them as self‐referential space(s), reordered by flexworkers as they seek to ‘keep the social moving’. The paper is based on an empirical study of employees in a Canadian subsidiary of a large hi‐tech multinational corporation. It examines organizational policy documents and interviews with managerial and non‐managerial flexworkers to identify how social and spatial relations are reordered and performed.     

Will the Truth Set Us Free? An Exploration of CSR Motive and Commitment

This article examines why firms engage in Corporate Social Responsibility (CSR). Specifically, it investigates the relationship between a firm's motivation to engage in CSR and the depth of its commitment. I propose that the enduring debate over CSR and financial performance is misaligned, and that scholars should instead focus on the underlying components of CSR engagement. This research sheds light on the motivational antecedents of a firm's engagement in CSR and their effect on CSR commitment. Despite calls for scientific investigation of this linkage, it has received scant attention in the literature. Pursuing this area of research requires the construction of measures of CSR motivation and CSR commitment, as prior work generally lacks objective analysis. I present measures and a research methodology that test hypotheses about how CSR motivation relates to different levels of CSR commitment. The results of this research both validate and challenge current theory. This refined understanding of CSR engagement may enhance firm transparency and accountability to stakeholders. It may reduce the uncertainty in both internal and external assessments of firm CSR and the potential for social and financial impact.     

The Negotiation of Child Care and Employment Demands Among Low-Income Parents

Low-income working mothers face significant child care challenges. These challenges are particularly salient in an era of welfare reform, when welfare recipients are under increased pressure to find a job. The current study examines how child care demands are negotiated for an urban sample of low-income mothers. The sample includes a racially and ethnically diverse group of 57 respondents with and without welfare experience who are mothering children under 13 years of age and working in entry-level jobs. Findings suggest that respondents seek arrangements that are affordable, convenient, and safe, and informal arrangements may be most compatible with convenience and cost considerations. Informal care is not universally available, however, andmay be less reliable. Implications for child care policy are discussed.     

Health-Based Population Forecasting: Effects of Smoking on Mortality and Fertility

A microsimulation model, allowing one to forecast short- and long-term population changes conditional on the prevalence of a risk factor in a population, is presented. In this model, population changes result from the aggregation of changes in individual event histories, which, in turn, result from mortality and infertility rates recalculated in accordance with their known relative risks in population groups exposed to a risk factor. Smoking, being the most widespread and influential preventable public health risk factor, is chosen to demonstrate the abilities of the model to forecast the population effects of different hypothetical smoking prevalences. The demographic and population health effects on 20-, 50-, and 100-year projections with the current, hypothetically doubled, and hypothetically halved the current smoking prevalence are analyzed in detail. The model predicts an increase in life expectancy (0.99 year for males and 0.64 years for females), and an increase in population size (2.2-7.5% dependent on the age group) if smoking prevalence is reduced by half. Sensitivity analyses of all findings are performed. The generalization of the model to account for multiple risk factors (e.g., the simultaneous effects of alcohol consumption, obesity, and smoking) and effects on medical expenditures are discussed.     

The swine flu vaccine and Guillain-Barré syndrome. A case study in relative risk and specific causation

Epidemiologic methods were developed to prove general causation: identifying exposures that increase the risk of particular diseases. Courts often are more interested in specific causation: On balance of probabilities, was the plaintiff's disease caused by exposure to the agent in question? Some authorities have suggested that a relative risk greater than 2.0 meets the standard of proof for specific causation. Such a definite criterion is appealing, but there are difficulties. Bias and confounding are familiar problems; individual differences must be considered too. The issues are explored in the context of the swine flu vaccine and Guillain-Barré syndrome. THE CONCLUSION: There is a considerable gap between relative risks and proof of specific causation.     

Interaktion des <Emphasis Type="Italic">als ob</Emphasis>: Privatanleger und Anlageberater

Since the late nineties, stock market investments have become an attractive option for many who want to secure or improve their standard of living, although ?stocks“ are an obscure subject for most of them. They have to rely on investment consultants in banks. Until the stock market crash, there was no reason to complain about the consulting process — shares kept going up in value.But it is remarkable that following the crash, which caused many investors to lose a large amount of money, the relationship between private investors and investment consultants does not seem to have been damaged.In our paper we first show the legal requirements for investment consulting and how these requirements are implemented by banks, and we identify considerable discrepancies between the theoretical and the actual fulfillment of these legal requirements.We then show that it is impossible to meet these requirements in reality because they rely on unrealistic assumptions regarding a consulting process that both adequately covers investment options and addresses the needs of investors. We argue that both sides are more or less satisfied with the situation because they operate on an as if basis: consultant and client talk and behave as if they understood each other.As if the consultant had really informed the client and as if the client had really understood the consultant. This as if which both parties are aware of but which is not openly discussed is the condition of a successful consultancy process and for making the business happen.