A random-effects model for cycle viability in fertility studies

The authors describe a random-effects fertility model based upon the assumption that the menstrual cycle viability probability varies from couple to couple according to a beta distribution. An EM algorithm is used to fit the model. The proposed estimating procedure is fully expandable to allow covariate effects on the beta variate. The method can be applied generally whenever dependency among Bernoulli trials is induced by a susceptibility state and the outcomes can be observed only in the aggregate. Based upon data from a cohort of 221 couples with no known fertility problems who were attempting pregnancy, cycle viability was found to be heterogeneous among couples. Stratification on the presence or absence of prenatal exposure of the woman to her mother's cigarette smoking revealed a statistically significant difference in the two-cycle viability distributions. Differences are discussed in the interpretation of the beta model compared to the marginal approach based upon generalized estimating equations.     

Engaging physicians in cost savings initiatives. Eliminating medication cost bias in the selection of inpatient medications

Higher cost medications pose a serious question for physician executives. Learn how common administrative databases can provide clinical resource utilization and identify success factors and barriers to devising cost-effective medical management strategies.     

Umhlaba 1913–2013

This essay argues that the violent explosion at Marikana is an indication that ordinary South Africans are rapidly losing faith in the democratic institutions and social contract arrangements that underpin the 1994 post-apartheid South African democratic social contract, whether Parliament, the collective bargaining system, or the National Economic Development and Labour Council (Nedlac). Similarly, “legitimate” institutions, such as political parties, trade unions and civic organisations – the organisations which pre-date 1994 – are also increasingly experienced by their members and supporters as not responsive, relevant or accountable. Marikana shows that if democratic institutions and “legitimate” institutions do not become more responsive, accountable and democratic quickly, ordinary people will increasingly look to new ones, including populists ones, or seek answers in violence. The essay concludes that although there are still many democratic and “legitimate” institutions which generate high levels of trust and enjoy widespread credibility and legitimacy, South Africa may have to renew aspects of its democratic social contract, institutions and rules, and in some cases, even create new, more relevant ones.