Bayesian multivariate mixed-scale density estimation

Although continuous density estimation has received abundant attention in the Bayesian nonparametrics literature, there is limited theory on multivariate mixed scale density estimation. In this note, we consider a general framework to jointly model continuous, count and categorical variables under a nonparametric prior, which is induced through rounding latent variables having an unknown density with respect to Lebesgue measure. For the proposed class of priors, we provide sufficient conditions for large support, strong consistency and rates of posterior contraction. These conditions allow one to convert sufficient conditions obtained in the setting of multivariate continuous density estimation to the mixed scale case. To illustrate the procedure a rounded multivariate nonparametric mixture of Gaussians is introduced and applied to a crime and communities dataset

A Conversation with Shoutir Kishore Chatterjee

Shoutir Kishore Chatterjee was born in Ranchi, a small hill station in India, on November 6, 1934. He received his B.Sc. in statistics from the Presidency College, Calcutta, in 1954, and M.Sc. and Ph.D. degrees in statistics from the University of Calcutta in 1956 and 1962, respectively. He was appointed a lecturer in the Department of Statistics, University of Calcutta, in 1960 and was a member of its faculty until his retirement as a professor in 1997. Indeed, from the 1970s he steered the teaching and research activities of the department for the next three decades. Professor Chatterjee was the National Lecturer in Statistics (1985--1986) of the University Grants Commission, India, the President of the Section of Statistics of the Indian Science Congress (1989) and an Emeritus Scientist (1997--2000) of the Council of Scientific and Industrial Research, India. Professor Chatterjee, affectionately known as SKC to his students and admirers, is a truly exceptional person who embodies the spirit of eternal India. He firmly believes that ``fulfillment in man's life does not come from amassing a lot of money, after the threshold of what is required for achieving a decent living is crossed. It does not come even from peer recognition for intellectual achievements. Of course, one has to work and toil a lot before one realizes these facts.''Comment: Published in at http://dx.doi.org/10.1214/088342306000000565 the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

Employee Heterogeneity and Within-Firm Experience-Earnings Profiles: A Nonparametric Analysis

Abstract Motivated by a priori uncertainty with respect to the parametric specification of the earnings function, I model the earnings function as semiparametric partially linear model and follow the estimation approach described in Robinson (1988). Using data from the personnel records of a large major UK based financial sector employer, I let years of within-firm and pre-firm experience form the nonparametrically modelled component of the earnings function. It is shown that the estimated within-firm experience earnings profiles, which are conditional upon a given number years of pre-firm experience accumulated before entry, converge and even overtake as years of pre-firm experience increases. This result can be explained with the recognition of unobservable explanatory variables, such as the match and individual quality of the employees, both of which are a function of years of within- and pre-firm experience and wages

"Suicide and Life Insurance"

In this paper, we investigate the nexus between life insurance and suicide behavior using OECD cross-country data from 1980 to 2002. Through semiparametric instrumental variable regressions with fixed effects, we find that for the majority of observations, there exists a positive relationship between suicide rate and life insurance density (premium per capita). Since life insurance policies pay death benefits even in suicide cases after the suicide exemption period, the presence of adverse selection and moral hazard suggests an incentive effect that leads to this positive relationship. The novelty of our analysis lies in the use of cross-country variations in the length of the suicide exemption period in life insurance policies as the identifying instrument for life insurance density. Our results provide compelling evidence suggesting the existence of adverse selection and moral hazards in life insurance markets in OECD countries.

Regional Agricultural Endowments and Shifts of Poverty Trap Equilibria: Evidence from Ethiopian Panel Data

We introduce new approaches to research on poverty traps, focusing on changes in patterns of equilibria over time and across regions, applied to the Ethiopia Rural Household Survey. We revisit the incidence of multiple equilibria using new nonparametric techniques; we also emphasize conditions of single equilibria that remain stagnant below the poverty line. We identify a single equilibrium in our initial interval (1994 - 1999) but and evidence that a second, higher equilibrium is emerging in the subsequent (1999 - 2004) interval. One of three major regions exhibits a deeply impoverished equilibrium that does not improve despite a national environment of pro-poor growth.poverty trap, Ethiopia, multiple equilibria, asset dynamics, regional poverty, sequence of equilibria