LOWER BOUNDS FOR THE DIVERGENCE OF DIRECTIONAL AND AXIAL ESTIMATORS

Consider estimation of a unit vector parameter a in two classes of distributions. In the first, α is a direction. In the second, α is an axis, so that –α and α are equivalent: the aim is to obtain the projector αα^t. In each case the paper uses first principles to define measures of the divergence of such estimators and derives lower bounds for them. These bounds are computed explicitly for the Fisher-Von Mises and Scheidegger-Watson densities on the g-dimensional sphere, ω_q. In the latter case, the tightness of the bound is established by simulations.     

Large sample theory of the Langevin distribution

The Langevin (or von Mises-Fisher) distribution of random vector x on the unit sphere ω_q in $\text{R}$^q has a density proportional to exp κμ'x where μ'x is the scalar product of x with the unit modal vector μ and κ?0 is a concentration parameter. This paper studies estimation and tests for a wide variety of situations when the sample sizes are large. Geometrically simple test statistics are given for many sample problems even when the populations may have unequal concentration parameters.     

Modeling the Impact of the Affordable Care Act and the Individual Mandate on Californians

The Patient Protection and Affordable Care Act (ACA) was designed to provide health insurance to uninsured or underinsured individuals. We used the California Simulation of Insurance Markets (CalSIM) model to predict the experience of consumers in California, who will be faced with new insurance options through Medicaid, employer-sponsored insurance, and the individual market in 2014 and beyond. We explored the response and characteristics of Californians who will and will not secure insurance coverage, with and without the “individual mandate” or minimum coverage requirement (MCR). We found 1.8 million Californians (38 %) of the 4.7 million eligible uninsured will secure coverage by 2019 with the MCR, while only 839,000 (18 % of the eligible uninsured) would obtain coverage without it.     

Re-thinking Transition: Globalism,Gender and Class

This article addresses the questions the ending of the Cold War raises for the understanding of gender and politics. It starts with the surprise that has been caused by the events of transition, and reflects this back to ask how expectations of transition which have consistently not been fulfilled, are produced. Why did feminism not develop in the wake of state socialism in the way many thought that it would? An argument is put forward to show how an idea of the West and of liberal freedom is at stake in the interpretation of the events of postcommunism. The article analyses how an idea of western freedom, which presupposes that identities under democratic and communist regimes are the same, also underpins tensions in West–East transnational feminist debate. A reconceptualization of transition is offered, first through a critique of the Newtonian concept of absolute space that underpins the idea of liberal freedom and the way in which this operates in civil society discourse. Second, a new analytical framework is offered, using the alternative, relativistic, concept of 'curved space'. Unlike the notion of absolute space, 'curved space' cannot be defined in the abstract, but is produced by and produces the specific identities which exist at any given moment in time. Different processes of identity formation in the West and in the East, can thus be related to differences in the curvature of space, that is, to the differences, in communist and democratic regimes, of relations of power. These power relation differences are a reflection of the organization of the economy-state. The article then shows how the hierarchization of citizenship is implied in the state/economy changes being put in place in the former Soviet Bloc. The institutionalization of gender after communism can be seen as part of an historically unprecedented process of social differentiation implicated in the re-introduction of private rights, and in the market economy and class relations which for the first time in history, are being required and instituted by (supra)states.     

‘The Times They Are A Changing’—Post Qualifying Training Needs of Social Work Managers

The article will focus on the changing role of social work managers in the light of recent legislation and policy; the integration agenda; the changing relationship between statutory and voluntary agencies; and the rising expectations of service users and carers. It will link these changes to the ongoing political and societal context in which social work is practised. The importance of effective social work management will be emphasised in the context of the recent enquiries into the deaths and long‐term abuse of service users. It will consider the issues for training and development of social work managers and will conclude by considering the issues for providers of training and development, with particular reference to post qualifying academic social work management courses. It will highlight the types of learning experiences social work managers require, outline consultations with students and agencies, and suggest issues for the future.     

Nearly Optimal Tests When a Nuisance Parameter Is Present Under the Null Hypothesis

This paper considers nonstandard hypothesis testing problems that involve a nuisance parameter. We establish an upper bound on the weighted average power of all valid tests, and develop a numerical algorithm that determines a feasible test with power close to the bound. The approach is illustrated in six applications: inference about a linear regression coefficient when the sign of a control coefficient is known; small sample inference about the difference in means from two independent Gaussian samples from populations with potentially different variances; inference about the break date in structural break models with moderate break magnitude; predictability tests when the regressor is highly persistent; inference about an interval identified parameter; and inference about a linear regression coefficient when the necessity of a control is in doubt.