The Box–Cox Transformation and Non‐Iterative Estimation Methods for Ordinal Log‐Linear Models

Recently Beh and Farver investigated and evaluated three non‐iterative procedures for estimating the linear‐by‐linear parameter of an ordinal log‐linear model. The study demonstrated that these non‐iterative techniques provide estimates that are, for most types of contingency tables, statistically indistinguishable from estimates from Newton's unidimensional algorithm. Here we show how two of these techniques are related using the Box–Cox transformation. We also show that by using this transformation, accurate non‐iterative estimates are achievable even when a contingency table contains sampling zeros.     

A note on bias reduction of maximum likelihood estimates for the scalar skew t distribution

The skew t distribution is a flexible parametric family to fit data, because it includes parameters that let us regulate skewness and kurtosis. A problem with this distribution is that, for moderate sample sizes, the maximum likelihood estimator of the shape parameter is infinite with positive probability. In order to try to solve this problem, Sartori (2006) has proposed using a modified score function as an estimating equation for the shape parameter. In this note we prove that the resulting modified maximum likelihood estimator is always finite, considering the degrees of freedom as known and greater than or equal to 2.     

SOS—Satisfied or Stuck,Why Older Rural Residents Stay Put: Aging in Place or Stuck in Place in Rural Utah*

As rural communities undergo substantial demographic and economic changes, understanding the migration intentions and their antecedents of rural elderly persons becomes increasingly important. Using data drawn from a survey of adults from 24 rural Utah communities conducted in 2008, we examine whether rural residents 60 years of age or older plan to remain in their present communities (N= 621). We use structural equation models (SEM) to estimate the relationships between a variety of individual and community-level background measures, including perceptions of local service quality, leaving one's community for health care, Internet use, attachment to and satisfaction with community, and plans to age in place. Results suggest that even as the rural context of economic decline, population loss, and distance to medical services may reduce the viability of staying in a community, a desire to remain in the community is primarily a function of perceptions of the quality of local services and community satisfaction. This research highlights the need to better understand the interplay between the availability of medical services and perceptions of distance as well as to understand the complex relationship between individual and community level characteristics for migration intentions.     

Time series models based on the unrestricted skew-normal process

The standard location and scale unrestricted (or unified) skew-normal (SUN) family studied by Arellano-Valle and Genton [On fundamental skew distributions. J Multivar Anal. 2005;96:93–116] and Arellano-Valle and Azzalini [On the unification of families of skew-normal distributions. Scand J Stat. 2006;33:561–574], allows the modelling of data which is symmetrically or asymmetrically distributed. The family has a number of advantages suitable for the analysis of stochastic processes such as Auto-Regressive Moving-Average (ARMA) models, including being closed under linear combinations, being able to satisfy the consistency condition of Kolmogorov’s theorem and providing the guarantee of the existence of such a SUN stochastic process. The family is able to be represented in a hierarchical form which can be used for the ease of simulation. In addition, it facilitates an EM-type algorithm to estimate the model parameters. The performances and suitability of the proposed model are demonstrated on simulations and using two real data sets in applications.     

Gambling motivations and superstitious beliefs: a cross-cultural study with casino customers

The expansion of legalized commercial gaming in Macau has motivated stakeholders to explore opportunities in other Asian countries. However, there is a lack of research focusing on casino customers in these markets. Thus, the purpose of this study is to explore gambling superstitious beliefs and motivations of those visiting a casino in South Korea, and how these factors are different across four ethnic groups. The researchers surveyed 323 casino customers in the lounge area on the casino floor, including Americans, Chinese, Japanese, and Koreans living abroad. This study found American gamblers could be characterized as more superstitious than Japanese gamblers, while the Chinese and American gamblers exhibited many similarities regarding the pattern of superstitious beliefs that they were most likely to endorse. The findings also suggest the culture and the area around the casino might be more important to Chinese, while novelty to Japanese and winning money to Korean gamblers are seen as most important. This study contributes to gambling literature by examining gamblers’ beliefs and motives in a different setting with more diverse populations than those in previous studies. The findings of this study will help casino operators properly develop and adjust strategies to thrive in the Asian marketplace.     

Utilizing Bayesian predictive power in clinical trial design

The Bayesian paradigm provides an ideal platform to update uncertainties and carry them over into the future in the presence of data. Bayesian predictive power (BPP) reflects our belief in the eventual success of a clinical trial to meet its goals. In this paper we derive mathematical expressions for the most common types of outcomes, to make the BPP accessible to practitioners, facilitate fast computations in adaptive trial design simulations that use interim futility monitoring, and propose an organized BPP-based phase II-to-phase III design framework.     

Heterogeneity in treatment effects across diverse populations

Differences in patient characteristics, including age, sex, and race influence the safety and effectiveness of drugs, biologic products, and medical devices. Here we provide a summary of the topics discussed during the opening panel at the 2018 Johns Hopkins Center for Excellence in Regulatory Science and Innovation symposium on Assessing and Communicating Heterogeneity of Treatment Effects for Patient Subpopulations: Challenges and Opportunities. The goal of this session was to provide a brief overview of FDA-regulated therapeutics, including drugs, biologics and medical devices, and some of the major sources of heterogeneity of treatment effects (HTE) related to patient demographics, such as age, sex and race. The panel discussed the US Food and Drug Administration's role in reviewing and regulating drugs, devices, and biologic products and the challenges associated with ensuring that diverse patient populations benefit from these therapeutics. Ultimately, ensuring diverse demographic inclusion in clinical trials, and designing basic and clinical research studies to account for the intended patient population's age, sex, race, and genetic factors among other characteristics, will lead to better, safer therapies for diverse patient populations.     

What is Sexual Satisfaction? Thematic Analysis of Lay People's Definitions

Sexual satisfaction is an important indicator of sexual health and is strongly associated with relationship satisfaction. However, research exploring lay definitions of sexual satisfaction has been scarce. We present thematic analysis of written responses of 449 women and 311 men to the question “How would you define sexual satisfaction?” The participants were heterosexual individuals with a mean age of 36.05 years (SD = 8.34) involved in a committed exclusive relationship. In this exploratory study, two main themes were identified: personal sexual well-being and dyadic processes. The first theme focuses on the positive aspects of individual sexual experience, such as pleasure, positive feelings, arousal, sexual openness, and orgasm. The second theme emphasizes relational dimensions, such as mutuality, romance, expression of feelings, creativity, acting out desires, and frequency of sexual activity. Our results highlight that mutual pleasure is a crucial component of sexual satisfaction and that sexual satisfaction derives from positive sexual experiences and not from the absence of conflict or dysfunction. The findings support definitions and models of sexual satisfaction that focus on positive sexual outcomes and the use of measures that incorporate items linked to personal and dyadic sexual rewards for both men and women.