Wealth: Determinants of Savings Net Worth and Housing Net Worth of Pre-Retired Households

The objectives of this study are to determine effects of household members' characteristics, financial resources, and attitude toward intergenerational support on change in savings net worth and change in housing net worth. Subsamples of White respondents, Black respondents, and Hispanic respondents were analyzed to identify the effects of race or ethnicity on the dependent variables. Attitude toward intergenerational support was the intervening variable. Change in labor income had a positive impact on change in savings net worth for all three racial or ethnic groups. An additional child in a household and an older age of the household head were likely to decrease the change in savings net worth. Effects of the remaining variables differed by subsample. The effects of labor and nonlabor income were different for the change in savings net worth but not for the change in housing net worth. Some different effects for variables across the three racial or ethnic groups were noted.     

Risk Analysis: Celebrating the Accomplishments and Embracing Ongoing Challenges

As part of the celebration of the 40th anniversary of the Society for Risk Analysis and Risk Analysis: An International Journal, this essay reviews the 10 most important accomplishments of risk analysis from 1980 to 2010, outlines major accomplishments in three major categories from 2011 to 2019, discusses how editors circulate authors’ accomplishments, and proposes 10 major risk-related challenges for 2020–2030. Authors conclude that the next decade will severely test the field of risk analysis.     

A natural conjugate prior for the nonhomogeneous poisson process with an exponential intensity function

This article presents a natural conjugate prior for the nonhomogeneous Poisson process (NHPP) with an exponential intensity function, for modeling the failure rate of repairable systems. The behavior of the conjugate prior distribution with respect to its parameters is studied, and the use of this prior in Bayesian estimation is compared to two other estimation approaches (the use of independent prior distributions, and the bivariate normal distribution). The use of the conjugate prior proposed here facilitates Bayesian statistical analysis of aging. In particular, the proposed prior allows us to explicitly account for dependence between the initial failure rate and the aging rate. This is a significant improvement over the assumptions made in most prior work (either the assumption that the aging rate is known, or the assumption that the initial failure rate and the aging rate are independent). Monte Carlo simulation shows that Bayesian estimation using the proposed prior generally performs at least as well as Bayesian estimation using independent priors for the initial failure rate and the aging rate,except in the case where the prior distribution underestimates both the initial failure rate and the aging rate.     

The U.S. Nuclear Regulatory Commission Safety Goal Policy: A Critical Review

The most recent U.S. Nuclear Regulatory Commission (NRC) statement of safety goal policy is a significant advance over previous versions. However, some areas of the policy are still in need of refinement, and the resolution of several key questions was deferred pending further review. To clarify some of these issues, this paper presents a critical review of the NRC safety goal policy to date.     

Binary Relations: Finite Characterizations and Computational Complexity

A characterization of a property of binary relations is of finite type if it is stated in terms of ordered T-tuples of alternatives for some positive integer T. The concept was introduced informally by Knoblauch (2005). We give a clear, complete definition below. We prove that a characterization of finite type can be used to determine in polynomial time whether a binary relation over a finite set has the property characterized. We also prove a simple but useful nonexistence theorem and apply it to three examples.