Bayesian correction for covariate measurement error: a frequentist evaluation and comparison with regression calibration

Bayesian approaches for handling covariate measurement error are well established, and yet arguably are still relatively little used by researchers. For some this is likely due to unfamiliarity or disagreement with the Bayesian inferential paradigm. For others a contributory factor is the inability of standard statistical packages to perform such Bayesian analyses. In this paper we first give an overview of the Bayesian approach to handling covariate measurement error, and contrast it with regression calibration (RC), arguably the most commonly adopted approach. We then argue why the Bayesian approach has a number of statistical advantages compared to RC, and demonstrate that implementing the Bayesian approach is usually quite feasible for the analyst. Next we describe the closely related maximum likelihood and multiple imputation approaches, and explain why we believe the Bayesian approach to generally be preferable. We then empirically compare the frequentist properties of RC and the Bayesian approach through simulation studies. The flexibility of the Bayesian approach to handle both measurement error and missing data is then illustrated through an analysis of data from the Third National Health and Nutrition Examination Survey

The Emerging Role of Group Medicare Private Fee-for-Service Plans

Examines the legislative and regulatory changes contributing to the rapid growth of enrollment in group Medicare Advantage plans in private fee-for-service plans. Considers projected trends and implications for retirees, employers, and policy makers

Towards the ‘Big Society’: What role for neighbourhood working? Evidence from a comparative European study

Under the New Labour government, the neighbourhood emerged prominently as a site for policy interventions and as a space for civic activity, resulting in the widespread establishment of neighbourhood-level structures for decision-making and service delivery. The future existence and utility of these arrangements is now unclear under the Coalition government's Big Society proposals and fiscal austerity measures. On the one hand, sub-local governance structures might be seen as promoting central-to-local and local-to-community devolution of decision-making. On the other, they might be seen as layers of expensive bureaucracy standing in the way of bottom-up community action. Arguably the current value and future role of these structures in facilitating the Big Society will depend on how they are constituted and with what purpose. There are many local variations. In this paper we look at three case studies, in England, France and the Netherlands, to learn how different approaches to neighbourhood working have facilitated and constrained civic participation and action. Drawing on the work of Lowndes and Sullivan (2008) we show how the achievement of civic objectives can be hampered in structures set up primarily to achieve social, economic and political goals, partly because of (remediable) flaws in civic engagement but partly because of the inherent tensions between these objectives in relation to issues of spatial scale and the constitution and function of neighbourhood structures. The purpose of neighbourhood structures needs to be clearly thought through. We also note a distinction between 'invited' and 'popular' spaces for citizen involvement, the latter being created by citizens themselves. 'Invited' spaces have tended to dominate to date, and the Coalition's agenda suggests a fundamental shift to 'popular' spaces. However we conclude that the Big Society will require neighbourhood working to be both invited and popular. Citizen participation cannot always replace local government - sometimes it requires its support and stimulation. The challenge for local authorities is to reconstitute 'invited' spaces (not to abolish them) and at the same time to facilitate 'popular' spaces for neighbourhood working.Big Society, local government, neighbourhood, neighbourhood management, community

Reducing the risks to health: the role of social protection: report of the Social Protection Task Group for the Strategic Review of Health Inequalities in England post 2010.

We demonstrate that the introduction of social protection systems as well as their generosity and coverage have significant impacts on health. Who receives the benefits within the household affects the health outcomes for the family. The eligibility for and administration of benefits matters. We examine the growth of means testing in the UK and its recent modifications. We find serious difficulties facing those with long term medical conditions who are on the margins of the labour force. Collaboration between the health and social protection systems is poor. We give particular attention to gender and health and the implications this has for the social protection system. We also consider the fate of groups like asylum seekers who are excluded from its normal working.

An automatic adaptive method to combine summary statistics in approximate Bayesian computation

To infer the parameters of mechanistic models with intractable likelihoods, techniques such as approximate Bayesian computation (ABC) are increasingly being adopted. One of the main disadvantages of ABC in practical situations, however, is that parameter inference must generally rely on summary statistics of the data. This is particularly the case for problems involving high-dimensional data, such as biological imaging experiments. However, some summary statistics contain more information about parameters of interest than others, and it is not always clear how to weight their contributions within the ABC framework. We address this problem by developing an automatic, adaptive algorithm that chooses weights for each summary statistic. Our algorithm aims to maximize the distance between the prior and the approximate posterior by automatically adapting the weights within the ABC distance function. Computationally, we use a nearest neighbour estimator of the distance between distributions. We justify the algorithm theoretically based on properties of the nearest neighbour distance estimator. To demonstrate the effectiveness of our algorithm, we apply it to a variety of test problems, including several stochastic models of biochemical reaction networks, and a spatial model of diffusion, and compare our results with existing algorithms

Are changes in neighbourhood perceptions associated with changes in self-rated mental health in adults? A 13 year repeat cross-sectional study, UK

The aim of this study was to examine changes in neighbourhood perceptions on self-rated mental health problems over time, and to explore demographic, geographic and socio-economic factors as determinants of increased or decreased anxiety and depression symptoms. We conducted a repeat cross-sectional study of individuals (N: 4480) living in the same areas of west central Scotland in 1997 and 2010. Individuals were asked to complete a questionnaire at both time-points, containing 14 questions relating to neighbourhood perceptions and the Hospital Anxiety and Depression Scale (HADS). A three-level linear regression model was fitted to HADS scores and changes in neighbourhood perceptions over time; controlling for a number of individual and area-level variables. Overall, area-level mean HADS scores decreased from 1997 to 2010. When adjusted for individual and area-level variables, this decrease did not remain for HADS anxiety. Applying an overall 14-scale neighbourhood perception measure, worsening neighbourhood perceptions were associated with small increases in depression (0.04, 95% confidence interval (CI) 0.01 to 0.07) and anxiety (0.04, 95% CI 0.00 to 0.08) scores over time. This highlights a need for local and national policy to target areas where neighbourhood characteristics are substantially deteriorating in order to ensure the mental health of individuals does not worsen

The Mass-Metallicity Relation for Giant Planets

Exoplanet discoveries of recent years have provided a great deal of new data for studying the bulk compositions of giant planets. Here we identify 47 transiting giant planets ($20 M_\oplus < M < 20 M_{\mathrm{J}}$) whose stellar insolation is low enough ($F_* < 2\times10^8\; \text{erg}\; \text{s}^{-1}\; \text{cm}^{-2}$, or roughly $T_\text{eff} < 1000$) that they are not affected by the hot Jupiter radius inflation mechanism(s). We compute a set of new thermal and structural evolution models and use these models in comparison with properties of the 47 transiting planets (mass, radius, age) to determine their heavy element masses. A clear correlation emerges between the planetary heavy element mass $M_z$ and the total planet mass, approximately of the form $M_z \propto \sqrt{M}$. This finding is consistent with the core accretion model of planet formation. We also study how stellar metallicity [Fe/H] affects planetary metal-enrichment and find a weaker correlation than has been previously reported from studies with smaller sample sizes. We confirm a strong relationship between the planetary metal-enrichment relative to the parent star $Z_{\rm planet}/Z_{\rm star}$ and the planetary mass, but see no relation in $Z_{\rm planet}/Z_{\rm star}$ with planet orbital properties or stellar mass. The large heavy element masses of many planets ($>50$ $M_{\oplus}$) suggest significant amounts of heavy elements in H/He envelopes, rather than cores, such that metal-enriched giant planet atmospheres should be the rule. We also discuss a model of core-accretion planet formation in a one-dimensional disk and show that it agrees well with our derived relation between mass and $Z_{\rm planet}/Z_{\rm star}$.Comment: Accepted to The Astrophysical Journal. This revision adds a substantial amount of discussion; the results are the sam