Asymptotic properties of the maximum smoothed partial likelihood estimator in the change-plane Cox model

The change-plane Cox model is a popular tool for the subgroup analysis of survival data. Despite the rich literature on this model, there has been limited investigation into the asymptotic properties of the estimators of the finite-dimensional parameter. Particularly, the convergence rate, not to mention the asymptotic distribution, has not been fully characterized for the general model where classification is based on multiple covariates. To bridge this theoretical gap, this study proposes a maximum smoothed partial likelihood estimator and establishes the following asymptotic properties. First, it shows that the convergence rate for the classification parameter can be arbitrarily close to $n^{-1}$ up to a logarithmic factor under a certain condition on covariates and the choice of tuning parameter. Given this convergence rate result, it also establishes the asymptotic normality for the regression parameter.     

The romance of leadership: Rekindling the fire through replication of Meindl and Ehrlich

Given changes in business and society, the romance of leadership theory, which describes a glorification of the perceived influence of leaders on organizational outcomes, is arguably more relevant than at its conception over thirty years ago. This paper presents four studies aimed to replicate Meindl and Ehrlich (1987) early experiment on the romance of leadership, specifically considering the effect of leadership attributions on company evaluations. Studies 1 and 2 are close replications, whereas Studies 3 and 4 provide a conceptual replication drawing from a broader sample in age and work experience and include additional experimental conditions. These conditions vary the gender of the leader and including both success and failure situations, as well as including additional outcomes variables of participants’ behavioral intentions to support, invest, seek employment, or purchase from the company. Taken together, these studies do not support Meindl and Ehrlich’s findings that organizations are viewed more favorably when such outcomes are attributed to leadership. We discuss implications for the romance of leadership theory.     

Approximate exchangeability and de Finetti priors in 2022

This is a review paper, beginning with de Finetti's work on partial exchangeability, continuing with his approach to approximate exchangeability, and then his (surprising) approach to assigning informative priors in nonstandard situations. Recent progress on Markov chain Monte Carlo methods for drawing conclusions is supplemented by a review of work by Gerencsér and Ottolini on getting honest bounds for rates of convergence. The paper concludes with a speculative approach to combining classical asymptotics with Monte Carlo. This promises real speed-ups and makes a nice example of how theory and computation can interact.     

Regression analysis of multivariate current status data under a varying coefficients additive hazards frailty model

This article discusses regression analysis of multivariate current status failure time data for which the observation time may be related to the underlying survival time. A local partial likelihood technique is used to estimate the varying coefficient covariate effect functions under the additive hazards frailty model. The asymptotic properties of the proposed estimators are established. An extensive simulation study is conducted for the evaluation of the proposed procedure, the results of which indicate that the proposed method works well in practice. Also, a real data study is provided to illustrate the performance of the proposed method.