Category Distinguishability and Observer Agreement

It is common in the medical, biological, and social sciences for the categories into which an object is classified not to have a fully objective definition. Theoretically speaking the categories are therefore not completely distinguishable. The practical extent of their distinguishability can be measured when two expert observers classify the same sample of objects. It is shown, under reasonable assumptions, that the matrix of joint classification probabilities is quasi-symmetric, and that the symmetric matrix component is non-negative definite. The degree of distinguishability between two categories is defined and is used to give a measure of overall category distinguishability. It is argued that the kappa measure of observer agreement is unsatisfactory as a measure of overall category distinguishability.     

Halfway There? Policy,Politics and Outcomes in Community Care

The community care reforms which followed the 1989 White Paper "Caring for People"were apparently focused on addressing the needs of people requiring long-term care, and on achieving improved outcomes and better quality of life.
The agenda set out by the White Paper was for community care in the next decade and beyond. Half way through this decade, we question the extent to which the objectives of promoting choice and independence for users and carers have been achieved. The paper draws particularly on a programme of monitoring conducted jointly by the Nuffield Institute for Health and the King's Fund, based on national and local focus groups meeting over a two-year period. It proposes a framework for evaluation which consists of four components: the definition of desired outcomes; specification of service systems necessary to deliver such outcomes; promotion of access to services; and the development of supporting operational policies and resource allocation mechanisms.
This framework offers a substantial step beyond much of the monitoring of the community care reforms which has taken place to date. This has assessed progress largely in terms of the establishment of new systems and processes. We conclude that such changes were essential building blocks for delivering better-quality community care services, and in the short term it may have been legitimate to view their establishment as proxies for progress towards delivering user-centred services. However, monitoring and evaluation should now be increasingly oriented towards ensuring that these changes are in fact producing the desired service outputs and urn outcomes. We propose that our framework offers one such way forward.     

伦理学视野下的当代英国少数族裔现状分析——以《偶发空缺》为例

J·K·罗琳的新作《偶发空缺》反映了英国当下少数族裔的生存现状。基于伦理学的视野,通过对从地女孩克里斯塔尔悲剧故事的分析,透析了资本主义社会在貌似公平友爱的社会福利制度下,中产阶级谋求话语权而排斥少数族裔以及少数族裔为身份、尊严而苦苦挣扎的现状,以期引起读者的深思。     

Dynamic network analysis of contact diaries

Analyzing two-mode networks linking actors to events they attend may help to uncover the structure and evolution of social networks. This classic social network insight is particularly valuable in the analysis of data extracted from contact diaries where contact events produce — and at the same time are the product of relations among participants. Contact events may comprise any number of actors meeting at a specific point in time. In this paper we recall the correspondence between two-mode actor–event networks and hypergraphs, and propose relational hyperevent models (RHEM) as a general modeling framework for networks of time-stamped multi-actor events in which the diarist (“ego”) simultaneously meets several of her alters. RHEM can estimate event intensities associated with each possible subset of actors that may jointly participate in events, and test network effects that may be of theoretical or empirical interest. Examples of such effects include preferential attachment, prior shared activity (familiarity), closure, and covariate effects explaining the propensity of actors to co-attend events. Statistical tests of these effects can uncover processes that govern the formation and evolution of informal groups among the diarist’s alters. We illustrate the empirical value of RHEM using data comprising almost 2000 meeting events of former British Prime Minister Margaret Thatcher with her cabinet ministers, transcribed from contact diaries covering her first term in office (1979–1983).     

Hepatitis C psychoeducation curriculum topics generated by group members

ABSTRACT

Educational programs for hepatitis C (HCV) have been created by professionals. There has not been a focus on whether what clients want to know about HCV differs from what providers want patients to know. This study addresses this gap by examining topics selected by participants in an education/support group model. Data were collected as part of a randomized psychoeducation trial for patients with HCV. Topics were systematically generated by the members uniquely for each group. Topics and rank order for each group were generated and a combined variable was created. Twenty-eight different topics were identified across 12 groups. The total number of topics was 102, averaging 8.5 per group. Topics are divided into three separate conceptual groups, members’ personal relationship to HCV, medical aspects of HCV, and unique concerns. A patient-centered approach that addresses the needs of HCV patients first provides an optimal starting point to discuss HCV disease management.     

An Exploration of Sexual Minority Stress Across the Lines of Gender and Sexual Identity

Despite growing evidence to suggest that gays, lesbians, and bisexuals experience a range of stressors and consequences related to their sexual minority status, no known studies to date have employed focus group discussion to explore and document their perceptions of sexual minority stress. In this exploratory study, we present focus group data on a range of sexual minority stressors as described by 43 gay men, lesbians, and bisexual men and women. We explore gender and sexual identity differences in the respondents' perceptions of heteronormativity, disclosure issues in different social settings, sources of support, and strategies for coping with stress. Respondents reported that women's same-sex relationships were eroticized and distorted to accommodate heterosexual male desire, while men were negatively depicted as sexually promiscuous and deviant. These differing stereotypes held important consequences for disclosure decisions and affected men's and women's social interactions with heterosexual men. Bisexual respondents reported unique strategies to cope with exclusion and isolation associated with misunderstandings about their sexual identities. Directions for future research on sexual minority stress are discussed.     

Book Reviews

Books reviewed:
M Hollander and D Wolfe, Nonparametric Statistical Methods
T Leonard and J.S.J Hsu, Bayesian Methods     

Gibbs sampling for marginal posterior expectations

In earlier work (Gelfand and Smith, 1990 and Gelfand et al, 1990) a sampling based approach using the Gibbs sampler was offered as a means for developing marginal posterior densities for a wide range of Bayesian problems several of which were previously inaccessible. Our purpose here is two-fold. First we flesh out the implementation of this approach for calculation of arbitrary expectations of interest. Secondly we offer comparison with perhaps the most prominent approach for calculating posterior expectations, analytic approximation involving application of the LaPlace method. Several illustrative examples are discussed as well. Clear advantages for the sampling based approach emerge.     

Sensitivity analysis for two control groups

In many experiments where data have been collected at two points in time (pre-treatment and post-treatment), investigators wish to determine if there is a difference between two treatment groups. In recent years it has been proposed that an appropriate statistical analysis to determine if treatment differences exist is to use the post-treatment values as the primary comparison variables and the pre-treatment values as covariates. When there are several outcome variables, we propose new tests based on residuals as alternatives to existing methods and investigate how the powers of the new and existing tests are affected by various choices of covariates. The limiting distribution of the test statistic of the new test based on residuals is given. Monte Carlo simulations are employed in the power comparisons.     

Predictive inference for linear and multivariate linear models with ma(1) error processes

The prediction distributions of future responses from the linear and multivariate linear models with errors having a first order moving average (MA(1)) process have been derived. First, we obtained the marginal likelihood function for the moving average parameter 6 and from this likelihood function we estimate the maximum likelihood estimates (MLE) of θ. Using the estimated value θ, we have derived the prediction distributions as well as prediction regions for the future responses. An example has been included.