The influence function of penalized regression estimators

To perform regression analysis in high dimensions, lasso or ridge estimation are a common choice. However, it has been shown that these methods are not robust to outliers. Therefore, alternatives as penalized M-estimation or the sparse least trimmed squares (LTS) estimator have been proposed. The robustness of these regression methods can be measured with the influence function. It quantifies the effect of infinitesimal perturbations in the data. Furthermore, it can be used to compute the asymptotic variance and the mean-squared error (MSE). In this paper we compute the influence function, the asymptotic variance and the MSE for penalized M-estimators and the sparse LTS estimator. The asymptotic biasedness of the estimators make the calculations non-standard. We show that only M-estimators with a loss function with a bounded derivative are robust against regression outliers. In particular, the lasso has an unbounded influence function.     

Mental Needs of Aboriginal Foster Parents

Aboriginal foster parents were surveyed about their mental needs. Each was asked “What do you need mentally to be a good foster parent?”. A total of 58 unique responses were made. They were grouped together by participants and the grouping data were analyzed using multidimensional scaling and cluster analysis. Seven concepts resulted from the analysis. The concepts included: knowledge, breaks, recognition, optimism, discipline, patience and determination. Results were compared and contrasted with the fostering literature.     

Learning (to) taste: food,aesthetics, and education in early modern France

ABSTRACT

This paper explores the intersection between taste and education in the early modern period. The first part investigates the close connection between the sense of taste and the sin of gluttony, highlighting taste’s close association with food disorders in the late Middle Ages and early modernity. Silencing taste was by then a key aspect of the education of the body, which needed to be learned from the earliest age, at home as well as at school. The second part charts the rise of a moderate and honest gourmandise from the late seventeenth and eighteenth centuries onward, accompanied by the invention of the polite bon goût and later the aesthetic taste of beauty, which contributed to a new social valorization of taste, while also complicating contemporary practices of learning (to) taste. Using a wide variety of early modern printed sources, including conduct books, religious and moral treatises, books of emblems, and treatises on the senses and on taste in particular, as well as aesthetic works, this paper sheds light on the multiple ways in which taste – of the body as much as of the mind – was used, learned, and displayed, hence revealing a transformation of the experience and understanding of taste throughout the early modern period, as well as its impact on educational practices.     

Hedging and accounting-based RPE contracts for powerful CEOs

Several firms prohibit their CEOs from trading in the stock of peer firms. This is puzzling since hedging by the CEO through private trading in the capital market can reduce the CEO’s exposure to systematic compensation risk. When the CEO’s incentive contract comprises relative performance evaluation, we find that the firm might want to disallow private hedging even though there are no technological interdependencies or strategic interactions to peer firms. In the analysis, we highlight two frequently observed characteristics of incentive contracts. First, the use of accounting benchmarks is widespread in compensation contracts for CEOs. Second, empirical and anecdotal evidence suggests that powerful CEOs have influence on the process of designing their own compensation. We find that in the presence of a powerful CEO, the firm can benefit from disallowing private hedging. In particular, the firm’s decision to allow or to disallow private hedging depends on the characteristics of the accounting benchmarks and the characteristics of the peer firms.