A pattern-mixture odds ratio model for incomplete categorical data

Most models for incomplete data are formulated within the selection model framework. Pattern-mixture models are increasingly seen as a viable alternative, both from an interpretational as well as from a computational point of view (Little 1993, Hogan and Laird 1997, Ekholm and Skinner 1998). Whereas most applications are either for continuous normally distributed data or for simplified categorical settings such as contingency tables, we show how a multivariate odds ratio model (Molenberghs and Lesaffre 1994, 1998) can be used to fit pattern-mixture models to repeated binary outcomes with continuous covariates. Apart from point estimation, useful methods for interval estimation are presented and data from a clinical study are analyzed to illustrate the methods.     

Determinants of Perceived Interfirm Dependence in Industrial Supplier Relations

Studies of industrial buyer-supplier relations mostly focus on structural characteristics of the transactions between parties, and assume a direct relation between these factors and characteristics of the relationships. This paper focuses on the psychological dimension of transaction relations, reflected in perceptions of dependence, from the perspective of an industrial supplier. In the first step of the analysis, three groups of structural determinants of perceived supplier dependence are explored: factors related to goal mediation, factors related to relation-specific assets, and factors related to network embeddedness. After that, the influence of these structural factors and of perceived supplier dependence on the ordering of buyer-supplier relations is investigated. Data come from a study of the micro-electronics assembly industry in the Netherlands. The findings show that sales to a particular buyer as a percentage of the total sales of the supplier and the growth of sales to a particular buyer (two forms of goal mediation) are important determinants of perceived supplier dependence. Human asset specificity is also related to perceived supplier dependence. Network embeddedness variables play only a minor role in explaining perceived supplier and buyer dependence in this study. The data further show that perceived dependence has an effect on the degree of ordering in the relationship, next to structural factors like the extendedness of the relationship beyond the focal transaction and physical asset specificity. The effects of human asset specificity and dedicated assets on ordering are contrary to what was expected on the basis of the literature.     

The Intervening Role of Relational Aggression between Psychological Control and Friendship Quality

This study investigated the associations among psychologically controlling parenting, relational aggression, friendship quality, and loneliness during adolescence. A model was proposed in which relational aggression plays an intervening role in the relations between both parental psychological control and friendship outcomes. In a sample comprised of middle adolescents and their parents, process analyses revealed that psychological control (indexed by parent and adolescent reports) positively predicted adolescents' self-reported relational aggression that, in turn, negatively predicted friendship quality and positively predicted loneliness. The model held for both mothers and fathers and was not moderated by adolescent gender. The discussion focuses on possible mechanisms explaining the relations among psychological control, relational aggression, and friendship outcomes.     

Flexicurity in Belgium: A reform proposal based on economic principles

Belgium's systems of unemployment insurance and employment protection legislation were set up in the context of typically enduring and stable relationships between workers and firms. Economic globalization and rapid technological and organizational change, however, are now demanding more flexibility of both workers and firms. As a result, current labour market institutions are in urgent need of reform to reconcile such increased flexibility with adequate security for workers. Though the call for a “flexicurity” approach is not new, there is no single view of what institutional model the latter implies. This paper proposes a reform explicitly guided by economic principles.     

Estimating the Risks of Smoking, Air Pollution, and Passive Smoke on Acute Respiratory Conditions

Five years of the annual Health Interview Survey, conducted by the National Center for Health Statistics, are used to estimate the effects of air pollution, smoking, and environmental tobacco smoke on respiratory restrictions in activity for adults, and bed disability for children. After adjusting for several socioeconomic factors, the multiple regression estimates indicate that an independent and statistically significant association exists between these three forms of air pollution and respiratory morbidity. The comparative risks of these exposures are computed and the plausibility of the relative risks is examined by comparing the equivalent doses with actual measurements of exposure taken in the homes of smokers. The results indicate that: (1) smokers will have a 55-75% excess in days with respiratory conditions severe enough to cause reductions in normal activity; (2) a 1 microgram increase in fine particulate matter air pollution is associated with a 3% excess in acute respiratory disease; and (3) a pack-a-day smoker will increase respiratory restricted days for a nonsmoking spouse by 20% and increase the number of bed disability days for young children living in the household by 20%. The results also indicate that the estimates of the effects of secondhand smoking on children are improved when the mother's work status is known and incorporated into the exposure estimate.     

Book Reviews

Books reviewed: Alan Walker and Chack‐kie Wong (eds), East Asian welfare regimes in transition: From Confucianism to globalization Robin Lovelock, Karen Lyons and Jackie Powell (eds), Reflecting on Social Work – Discipline and Profession Stephan Leibfried and Michael Zürn, Transformations of the State?     

Seizing the means of reproduction: An illegal feminist abortion collective—How and why it worked

This paper describes an illegal feminist abortion collective [the Service] through whose efforts 11,000 abortions were performed between 1969 and 1973 when abortion was legalized. An analysis of interviews from 32 members of this lay group indicates how and why the collective was so effective in providing what is usually a physician-controlled medical procedure. After describing the structure of the organization and the process by which women obtained the abortion, including pre-abortion counseling and post-abortion follow-up, two sets of reasons for the collective's effectiveness are presented. The first five reasons derive from the interview themselves; they deal with the organization's social and historical context, its illegality, its charismatic leaders, its member satisfaction and its financial self-sufficiency. The next nine reasons deal with factors that make The Service a relatively typical democratic collective organization. The most important of these factors is its lack of concern for organizational survival per se. This account supports the Rothschild-Whitt model for collective democratic organizations. It also suggests that counseling is important both for the providers and for the receivers of abortions.     

Mass Customization in the Automotive Industry: Comparing Interdealer Trading and Reconfiguration Flexibilities in Order Fulfillment

Mass customization has been viewed as desirable but difficult to achieve in the volume automotive sector. Here we consider flexibility in automotive order fulfillment systems to enhance the ability to satisfy customers with their desired vehicle variants within acceptable delivery lead times. Two types of flexibility are compared in a Virtual‐Build‐to‐Order system—reconfiguration in the planning pipeline and interdealer trading. A representative simulation model is used to investigate the impact of the two types of flexibility across a wide spectrum of product variety levels. The impacts on major stakeholders in the system—the producer, dealers, and customers—are considered. The study shows that both types of flexibilities can bring significant benefits in terms of reductions in lead time and inventory holding. The level of product variety strongly influences the observed effects—an important finding in the mass customization context. Upstream reconfiguration flexibility brings greater benefits than downstream trading flexibility. Reconfiguration tends to dominate trading as a fulfillment mechanism when both are in operation. The findings have implications for the design and management of automotive order fulfillment systems in improving their ability to offer mass customization. The study has relevance for companies in other sectors with high levels of variety that seek to combine efficiency, speed, and flexibility in order fulfillment.