An iterative self-weighting procedure for fitting straight lines to heteroscedastic data

An iterative, self-weighting procedure is presented for the fitting of straight lines to data with heteroscedastic error-variances in the response variable. The error-variances are assumed to be unknown, even relative to each other. The procedure is compared with the “resistant line” method advocated by Emerson and Hoaglin [Emerson and Hoaglin, 1983], using extensive Monte-Carlo calculations. The proposed method is simple and easily automated, and gives parameter-estimates with smaller variance (higher efficiency) than those resulting from the resistant line technique. A BASIC program to perform the self-weighting fit is given in an appendix     

A Framework for Random-Effects ROC Analysis: Biases with the Bootstrap and Other Variance Estimators

In this article, we analyze the three-way bootstrap estimate of the variance of the reader-averaged nonparametric area under the receiver operating characteristic (ROC) curve. The setting for this work is medical imaging, and the experimental design involves sampling from three distributions: a set of normal and diseased cases (patients), and a set of readers (doctors). The experiment we consider is fully crossed in that each reader reads each case. A reading generates a score that indicates the reader's level of suspicion that the patient is diseased. The distribution of scores for the normal patients is compared to the distribution of scores for the diseased patients via an ROC curve, and the area under the ROC curve (AUC) summarizes the reader's diagnostic ability to separate the normal patients from the diseased ones. We find that the bootstrap estimate of the variance of the reader-averaged AUC is biased, and we represent this bias in terms of moments of success outcomes. This representation helps unify and improve several current methods for multi-reader multi-case (MRMC) ROC analysis.     

Transforming mental health services to address gender disparities in depression risk factors

ABSTRACT

Depression in older women is a significant and growing problem. Women who experience life stressors across the life span are at higher risk for developing depression than their male counterparts. Research has focused primarily on identifying and reducing the symptoms of depression for the general aging population, disregarding gender-specific differences in the foundational causes of depression. This article examines how women’s unique experiences influence the development of depression and highlights how the current mental health system could better meet older women’s needs by moving from a gender-neutral model to one that emphasizes women’s experiences.     

Bayesian and Frequentist Inference in Partially Identified Models

A large‐sample approximation of the posterior distribution of partially identified structural parameters is derived for models that can be indexed by an identifiable finite‐dimensional reduced‐form parameter vector. It is used to analyze the differences between Bayesian credible sets and frequentist confidence sets. We define a plug‐in estimator of the identified set and show that asymptotically Bayesian highest‐posterior‐density sets exclude parts of the estimated identified set, whereas it is well known that frequentist confidence sets extend beyond the boundaries of the estimated identified set. We recommend reporting estimates of the identified set and information about the conditional prior along with Bayesian credible sets. A numerical illustration for a two‐player entry game is provided.     

When I'm 64: Psychological contract breach,work motivation and the moderating roles of future time perspective and regulatory focus

Abstract

There is an increasing need for managers to understand what motivates younger versus older workers to continue work within their company. We believe that this two-wave study among 90 Dutch employees is the first to examine: (1) the cross-lagged relationships between breach of psychological contract (which includes transactional and relational obligations) and intrinsic work motivation, and (2) the moderating role of the age-related variables future time perspective and regulatory focus. Regulatory focus concerns the orientation (either promotion-focused or prevention-focused) by which an individual pursues their goals. Based on psychological contract theory, we expected and found that relational contract breach predicts lower work motivation. Furthermore, based on lifespan developmental and regulatory focus theory, we assumed that this relationship would be stronger when workers experienced an open future time perspective and a promotion focus rather than a prevention focus. The results showed that future time perspective indeed had a strengthening, and prevention focus a reducing moderating effect in the relationship between psychological contract breach and work motivation. However, no significant effects for promotion focus were found. These findings indicate that age-related processes such as future time perspective and regulatory focus are important variables to include in future psychological contract research.     

Households’ preferences for attributes of Conditional Cash Transfer programmes: A choice experiment in Ghana

Conditional cash transfer (CCT) is increasingly being integrated into poverty reduction strategies in developing countries. However, debate remains over key elements of CCT programme design. Using a discrete choice model, this article examines Ghanaian households’ preferences regarding key CCT programme design elements including conditionality, targeting, and payment method. The results revealed a preference for CCT designs that target beneficiaries with limited or no productive capacity and CCT designs that are conditional on beneficiaries either investing in children's human capital or performing communal service, relative to unconditional programmes. Also, direct bank deposit was revealed as the preferred payment mode relative to receipt of cash payments or use of mobile money systems.     

Race‐Based Perceptual Asymmetry in Face Processing Is Evident Early in Life

Adults’ processing of own‐race faces differs from that of other‐race faces. The presence of an “other‐race” feature (ORF) has been proposed as a mechanism underlying this specialization. We examined whether this mechanism, which was previously identified in adults and in 9‐month‐olds, is evident at 3.5 months. Caucasian 3.5‐month‐olds looked longer at a pattern containing a single Asian face among seven Caucasian faces than at a pattern containing a single Caucasian face among seven Asian faces. Homogenous and inverted face control conditions indicated that infants’ preference was not driven by the majority of faces in arrays or by low‐level features. Thus, 3.5‐month‐olds found the presence of an other‐race face among own‐race faces to be more salient than the reverse configuration. This asymmetry suggests sensitivity to an ORF at 3.5 months. Thus, a key mechanism of race‐based processing in adults has an early onset, indicating rapid development of specialization early in life.     

Ellsberg games

In the standard formulation of game theory, agents use mixed strategies in the form of objective and probabilistically precise devices to conceal their actions. We introduce the larger set of probabilistically imprecise devices and study the consequences for the basic results on normal form games. While Nash equilibria remain equilibria in the extended game, there arise new Ellsberg equilibria with distinct outcomes, as we illustrate by negotiation games with three players. We characterize Ellsberg equilibria in two-person conflict and coordination games. These equilibria turn out to be related to experimental deviations from Nash equilibrium play.     

Campaigning in the fourth age of political communication. A multi-method study on the use of Facebook by German and Austrian parties in the 2013 national election campaigns

Starting from the contribution to the discussion on a fourth age of political communication, here we argue that, as a consequence of how the Web 2.0 has changed political campaigns, the theoretical time-bound three-phase models of political campaigning must be reconsidered. We propose four ideal campaign types based on their ideal-typical target audience: partisan-, mass-, target group- and individual-centered campaigns. In reality, each campaign combines elements of all types. To examine this mixture empirically, we apply a most similar systems design and investigate five German and six Austrian parties’ use of Facebook in the 2013 national election campaigns. On the basis of face-to-face interviews with the campaign managers and a quantitative content analysis of the respective parties’ Facebook pages, we analyze how parties used Facebook as a campaigning tool to inform, interact with, and mobilize voters, as well as which target audiences they addressed. We find that, although the campaign managers declare Facebook their most important Web 2.0 campaigning tool, the German and Austrian parties did not make use of Facebook’s interactive and mobilizing potential, rather relying on mass-centered information, possibly due to the framework conditions in both countries. Based on our findings, we conclude that the role of context for election campaigning should be discussed more carefully.