The Prevalence and Prevention of Crosstalk: A Multi-Institutional Study

It is a common problem in psychology subject pools for past study participants to inform future participants of key experimental details (also known as crosstalk). Previous research (Edlund, Sagarin, Skowronski, Johnson, & Kutter, 2009) demonstrated that a combined classroom and laboratory treatment could significantly reduce crosstalk. The present investigation tested a laboratory-only treatment for the prevention of crosstalk at five universities, along with institutional-level moderators of crosstalk. Results indicated the presence of crosstalk at all universities and that the laboratory-based treatment was effective in reducing crosstalk. Importantly, crosstalk rates were higher (but successfully neutralized) in research pools with higher research credit requirements. Therefore, this research provides valuable guidance regarding crosstalk prevalence and its minimization by researchers.     

大数据时代背景下的医学思考*--转化医学新趋势前瞻

作为21世纪最具活力的医学发展模式,转化医学为基础和临床构建了交流沟通的高效平台,当前正朝着多学科、多领域、多系统的方向迈进。随着信息技术与生命科学的交叉融合,生物医学已经迈入大数据时代。大数据既保证了医学实践的深度,有深度才能洞悉本质;又保证了医学实践的高度,有高度才能总揽全局。因此,大数据的出现为深陷还原论泥潭的现代医学提供了有效的解决途径。大数据浪潮对医学基础研究和医疗实践的深远影响,必将为转化医学发展带来新的发展机遇。     

Longitudinal Dynamics of Substance Use and Psychiatric Symptoms in Count Data with Zero Inflation

We examine the dynamics of substance use and psychiatric symptoms from childhood to adolescence using a longitudinal study of Mexican-origin families (N = 674). We present a longitudinal model capturing the trajectories of substance use and psychiatric symptoms (depression, conduct disorder), as well as the interrelations between these trajectories over time. Such a model is an extension of latent change score models designed to account for the occurrence of psychiatric symptoms while also accommodating a large amount of zeros for nonoccurrence and characterizing the changes over time in the count data. We compare this model with a more traditional approach based on a log transformation of the data. We describe differences between these approaches and highlight the benefits of using the two-part model when the data include a large amount of zeros for nonoccurrence of the behavior.     

Thurstonian Scaling of Compositional Questionnaire Data

To prevent response bias, personality questionnaires may use comparative response formats. These include forced choice, where respondents choose among a number of items, and quantitative comparisons, where respondents indicate the extent to which items are preferred to each other. The present article extends Thurstonian modeling of binary choice data to “proportion-of-total” (compositional) formats. Following the seminal work of Aitchison, compositional item data are transformed into log ratios, conceptualized as differences of latent item utilities. The mean and covariance structure of the log ratios is modeled using confirmatory factor analysis (CFA), where the item utilities are first-order factors, and personal attributes measured by a questionnaire are second-order factors. A simulation study with two sample sizes, N = 300 and N = 1,000, shows that the method provides very good recovery of true parameters and near-nominal rejection rates. The approach is illustrated with empirical data from N = 317 students, comparing model parameters obtained with compositional and Likert-scale versions of a Big Five measure. The results show that the proposed model successfully captures the latent structures and person scores on the measured traits.     

A Comparison of Two-Stage Approaches for Fitting Nonlinear Ordinary Differential Equation Models with Mixed Effects

Several approaches exist for estimating the derivatives of observed data for model exploration purposes, including functional data analysis (FDA; Ramsay &; Silverman, 2005 Ramsay, J. O., &; Silverman, B. W. (2005). Functional data analysis (2nd ed.). New York, NY: Springer-Verlag. [Google Scholar]), generalized local linear approximation (GLLA; Boker, Deboeck, Edler, &; Peel, 2010 Boker, S. M., Deboeck, P. R., Edler, C., &; Peel, P. K. (2010). Generalized local linear approximation of derivatives from time series. In S. Chow, E. Ferrer, &; F. Hsieh (Eds.), Statistical methods for modeling human dynamics: An interdisciplinary dialogue (pp. 161–178). New York, NY: Taylor &; Francis. [Google Scholar]), and generalized orthogonal local derivative approximation (GOLD; Deboeck, 2010 Deboeck, P. R. (2010). Estimating dynamical systms: Derivative estimation hints from Sir Ronald A. Fisher. Multivariate Behavioral Research, 45, 725–745. doi:10.1080/00273171.2010.498294[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]). These derivative estimation procedures can be used in a two-stage process to fit mixed effects ordinary differential equation (ODE) models. While the performance and utility of these routines for estimating linear ODEs have been established, they have not yet been evaluated in the context of nonlinear ODEs with mixed effects. We compared properties of the GLLA and GOLD to an FDA-based two-stage approach denoted herein as functional ordinary differential equation with mixed effects (FODEmixed) in a Monte Carlo (MC) study using a nonlinear coupled oscillators model with mixed effects. Simulation results showed that overall, the FODEmixed outperformed both the GLLA and GOLD across all the embedding dimensions considered, but a novel use of a fourth-order GLLA approach combined with very high embedding dimensions yielded estimation results that almost paralleled those from the FODEmixed. We discuss the strengths and limitations of each approach and demonstrate how output from each stage of FODEmixed may be used to inform empirical modeling of young children’s self-regulation.     

Using Marginal Structural Modeling for Grade Retention Effects

Vandecandelaere, Vansteelandt, De Fraine, and Van Damme (this issue) described marginal structural modeling (MSM) and used it to estimate the effects of a time-varying intervention, retention (holding back) in school grades, on students' math achievement. This commentary supplements Vandecandelaere et al. (this issue) and discusses several topics in retention studies and MSM. First, we discuss the importance of equating time-varying confounders in retention studies. Second, we discuss same-grade and same-age comparisons in retention studies. Third, we discuss one important section in the authors' overview of MSM: why standard methods (e.g., ANCOVA, propensity score analysis) cannot properly adjust for time-varying confounders. Finally, using the grade retention analyses in Vandecandelaere et al. (this issue) as an example, we provide our insights on four aspects of MSM: (a) covariate selection, (b) estimation of weights, (c) evaluation of balance properties, and (d) missing data handling.     

缺失数据的结构方程建模:全息极大似然估计时辅助变量的作用

本研究通过蒙特卡洛模拟考查了采用全息极大似然估计进行缺失数据建模时辅助变量的作用。具体考查了辅助变量与研究变量的共缺机制、共缺率、相关程度、辅助变量数目与样本量等因素对参数估计结果精确性的影响。结果表明,当辅助与研究变量共缺时:(1)对于完全随机缺失的辅助变量,结果更容易出现偏差;(2)对于MAR-MAR组合机制,纳入单个辅助变量是有益的;对于MAR-MCAR或MAR-MNAR组合机制,纳入多于一个辅助变量的效果更好;(3)纳入与研究变量低相关的辅助变量对结果也是有益的。     

Adult Missing Persons: Can an Investigative Framework be Generated Using Behavioural Themes?

There is a limited amount of research in the area of missing persons, especially adults. The aim of this research is to expand on the understanding of missing people, by examining adults' behaviours while missing and determining if distinct behavioural themes exist. Based on previous literature it was hypothesised that three behavioural themes will be present; dysfunctional, escape, and unintentional. Thirty‐six behaviours were coded from 362 missing person police reports and analysed using smallest space analysis (SSA). This produced a spatial representation of the behaviours, showing three distinct behavioural themes. Seventy percent of the adult missing person reports were classified under one dominant theme, 41% were ‘unintentional’, 18% were ‘dysfunctional’, and 11% were ‘escape’. The relationship between a missing person's dominant behavioural theme and their assigned risk level and demographic characteristics were also analysed. A significant association was found between the age, occupational status, whether they had any mental health issues, and the risk level assigned to the missing person; and their dominant behavioural theme. The findings are the first step in the development of a standardised checklist for a missing person investigation. This has implications on how practitioners prioritise missing adults, and interventions to prevent individuals from going missing. Copyright © 2016 John Wiley & Sons, Ltd.     

Personality change via work: A job demand–control model of Big-five personality changes

Based on the job demand–control model and Gray's biopsychological theory of personality, the author proposed a model to suggest that time demand and job control can drive changes in Big-five personality traits, especially neuroticism and extroversion, by shaping an individual's stress experiences at work. Five waves of data from 1814 employees over a five-year period from the Household, Income and Labor Dynamics in Australia Survey were analyzed. Time demand, job control and job stress were measured in all five waves, and Big-five personality was assessed in the first and last waves. The results showed that time demand and job control shaped job stress positively and negatively at a given time; and over time, an increase in time demand predicted an increase in job stress, which subsequently predicted an increase in neuroticism and a decrease in extroversion and conscientiousness. Results also showed that an increase in job control predicted an increase in agreeableness, conscientiousness, and openness directly, but did not predict change in neuroticism and extroversion. Finally, the buffering effect of job control on the association between time demand and job stress was only observed in two of five waves and such buffering effect was not observed in a change process. The implications on personality development and work design research are discussed.