Of employers,uncles and interpreters: the diverse trajectories of guest workers to the Belgian city of Ghent, 1960–1975

This article addresses a lesser-known part of post-war migration to Europe: the actual trajectories through which guest workers arrived in the countries of destination. Currently, these trajectories are explained through two models: that of large-scale employer recruitment and that of chain migration through personal networks. This article argues, however, that these two explanatory models oversimplify a complex historical reality. First, both models tend to be interpreted rather narrowly. Through an extensive discussion of the many different trajectories of guest workers to the Belgian city of Ghent, this article provides a more diffuse interpretation, focusing on the high degree of complexity within and overlap between them. Second, the existing models do not leave much space for a third category of agents: the so-called migration middlemen. This article places these middlemen in the spotlight, looking at their role as well as at their perception by contemporary actors. By providing a more encompassing picture of the actual migration trajectories of guest workers, of the many actors involved in them, and of the different migration regimes framing them, the article hopes to contribute to a better understanding of the ways in which people move not only in the past but also in the present.     

Evaluating dynamic treatment strategies: does it have to be more costly?

Dynamic treatment strategies are designed to change treatments over time in response to intermediate outcomes. They can be deployed for primary treatment as well as for the introduction of adjuvant treatment or other treatment‐enhancing interventions. When treatment interventions are delayed until needed, more cost‐efficient strategies will result. Sequential multiple assignment randomized (SMAR) trials allow for unbiased estimation of the marginal effects of different sequences of history‐dependent treatment decisions. Because a single SMAR trial enables evaluation of many different dynamic regimes at once, it is naturally thought to require larger sample sizes than the parallel randomized trial. In this paper, we compare power between SMAR trials studying a regime, where treatment boosting enters when triggered by an observed event, versus the parallel design, where a treatment boost is consistently prescribed over the entire study period. In some settings, we found that the dynamic design yields the more efficient trial for the detection of treatment activity. We develop one particular trial to compare a dynamic nursing intervention with telemonitoring for the enhancement of medication adherence in epilepsy patients. To this end, we derive from the SMAR trial data either an average of conditional treatment effects (‘conditional estimator’) or the population‐averaged (‘marginal’) estimator of the dynamic regimes. Analytical sample size calculations for the parallel design and the conditional estimator are compared with simulated results for the population‐averaged estimator. We conclude that in specific settings, well‐chosen SMAR designs may require fewer data for the development of more cost‐efficient treatment strategies than parallel designs. Copyright © 2012 John Wiley & Sons, Ltd.     

Variations of Sexual Scripts Relating to Concurrency by Race,Class, and Gender in South Africa

It is unclear whether higher rates of sexual partner concurrency in Black South Africans are due to socioeconomic or cultural factors. We used a nationally representative sample of 9,728 individuals aged 16 to 55 from a study conducted in 2009 to examine how the norms pertaining to concurrency and the practice of concurrency vary by race, class, and gender. The percentage of men reporting point concurrency was 14%, 6.5%, and 2.5% in Blacks, coloreds, and Whites, respectively (p < 0.001). These percentages increased to 45.7%, 24.7%, and 11.7%, respectively, for those reporting lifetime concurrency (p < 0.001). In all the racial groups, men exhibited more favorable attitudes toward concurrency than women did. For a range of indicators, White men and women had less favorable attitudes toward concurrency than Black men and women. These differences remained after controlling for a range of confounding variables. In the adjusted logistic regression model, reported concurrency in men was associated with a younger age, Black race, being in the lowest income tertile, not being in a stable relationship, and expressing various positive attitudes toward concurrency.