On a test of dimensionality in redundancy analysis

Lazraq and Cléroux (Psychometrika, 2002, 411–419) proposed a test for identifying the number of significant components in redundancy analysis. This test, however, is ill-conceived. A major problem is that it regards each redundancy component as if it were a single observed predictor variable, which cannot be justified except for the rare situations in which there is only one predictor variable. Consequently, the proposed test leads to drastically biased results, particularly when the number of predictor variables is large, and it cannot be recommended for use. This is shown both theoretically and by Monte Carlo studies.The work reported in this paper was supported by Grant A6394 to the first author from the Natural Sciences and Engineering Research Council of Canada.     

Age-related effects of practice experience on collective behaviours of football players in small-sided games

The purpose of this study was to examine whether offensive and defensive collective behaviours emerging in six-a-side football games (GK+5 vs. 5+GK) varied according to age-related practice experience of young, male players (U16, U17 and U19 yrs). Players’ were not instructed to implement specific tactical plans and their movement trajectories (2D analyses) were recorded using 10 GPS units. Four common measures of team dispersion investigated in previous research (surface area, stretch index, length and width of a team) were used to analyse team performance behaviours. After recording these collective variables, we used sample entropy (SampEn) and cross-sample entropy (Cross-SampEn) measures to assess the regularity and synchronization of participant actions in teams. Results demonstrated clear age-related variations in effects on the collective performance measures analysed. In attacking phases, older and more experienced players occupied a greater surface area and displayed higher values of team width and stretch index. In defensive phases, significant differences were observed in team length and stretch index. Cross-SampEn analysis demonstrated a greater synchronization between offensive and defensive surface areas and team width in older age groups (U17 and U19 yrs). Data suggest how coaches can manipulate practice task constraints to enhance development of team tactical performance behaviours in developing footballers between 16 and 19 yrs of age.     

Inferring salesperson capability using stochastic frontier analysis

This paper proposes an easy-to-implement econometric method for inferring salesperson capability from archival panel data, namely stochastic frontier (SF) analysis. We demonstrate this method with a sample of salespersons provided by a life insurance company. Using the proposed SF model, we are able to estimate each salesperson’s capability. Furthermore, we examine the relationship between the estimated salesperson capability and three future outcomes (i.e. future sales performance, future customer attrition, and future salesperson turnover) under different time horizons. We find that, in general, the estimated salesperson capability has a stronger explanatory power for the near than for the more distant future. Since an individual salesperson’s capability cannot be directly observed by researchers (and thus is typically omitted), traditional analyses of sales performance suffer from an omitted-variable problem that can lead to biased estimates of focal variables. The SF model can significantly mitigate this omitted-variable problem. Statistical tests indicate that our sales performance model with estimated salesperson capability results in a statistically significant improvement in model fit. Of note, our model differs methodologically from SF models previously used in the marketing literature in that it is based on a three-component model that disentangles unobserved individual heterogeneity, efficiency, and random shocks.     

Shopping destination choice in Tehran: An integrated choice and latent variable approach

Integrated choice and latent variable (ICLV) models are increasingly considered in many fields as a means to gain a deeper understanding into the decision process of individuals as well as to potentially improve predictive ability. Literature has shown that the application of ICLV in context of shopping destination choice has not been conducted yet. This study uses data collected from the city of Tehran, Iran on shopping destination choice of 812 individuals. Then these attitudinal questions are used for the development of latent variables regarding the attitude and lifestyle of the participants. By including one latent variable (LV) reflecting the attitudes of clothing and lifestyle’s of grocery travelers the structural model reveals a sample distribution of this LV conditional on fundamental socio-economic characteristics. The results of our latent variable model clearly confirm that personal attitude toward clothing shopping center and lifestyle indeed impact destination choice. The results show that our experiment and the expanded hybrid choice model (HCM) allow appropriately identifying and investigating the effects of mixtures of latent attitudes on the intention shopping destination choice.     

第二类有中介的调节模型

心理学研究常用有中介的调节模型揭示调节作用通过中介变量间接实现的现象。介绍了第二类有中介的调节模型(meMO-II)的概念及优势; 将meMO-II与其它中介调节混合模型进行了辨析; 给出了meMO-II的建模方法和分析流程, 并用一个实例演示; 介绍了基于潜变量的meMO-II的分析方法、meMO-II建模方法的新进展以及meMO-II的变式。研究有助于推动调节机制研究的发展。     

Model Implied Instrumental Variables (MIIVs): An Alternative Orientation to Structural Equation Modeling

Few dispute that our models are approximations to reality. Yet when it comes to structural equation models (SEMs), we use estimators that assume true models (e.g. maximum likelihood) and that can create biased estimates when the model is inexact. This article presents an overview of the Model Implied Instrumental Variable (MIIV) approach to SEMs from Bollen (1996). The MIIV estimator using Two Stage Least Squares (2SLS), MIIV-2SLS, has greater robustness to structural misspecifications than system wide estimators. In addition, the MIIV-2SLS estimator is asymptotically distribution free. Furthermore, MIIV-2SLS has equation-based overidentification tests that can help pinpoint misspecifications. Beyond these features, the MIIV approach has other desirable qualities. MIIV methods apply to higher order factor analyses, categorical measures, growth curve models, dynamic factor analysis, and nonlinear latent variables. Finally, MIIV-2SLS permits researchers to estimate and test only the latent variable model or any other subset of equations. In addition, other MIIV estimators beyond 2SLS are available. Despite these promising features, research is needed to better understand its performance under a variety of conditions that represent empirical applications. Empirical and simulation examples in the article illustrate the MIIV orientation to SEMs and highlight an R package MIIVsem that implements MIIV-2SLS.     

The effects of self-disclosure on the communicative interaction between a person who stutters and a normally fluent speaker

PurposeThe purpose of this study was to investigate the effects of self-disclosure on the self-perception of stuttering severity, comfort, cognitive effort, and anxiety in a structured conversational interaction with a normally fluent speaker. The benefit of self-disclosure from the perspective of the person who stutters in a self-disclosed and in a non-disclosed condition was also studied. The total syllables produced and percent syllables stuttered were measured in both experimental conditions in order to evaluate the effects on the amount of speech produced and verbal fluency.MethodsTwenty-five adults who stutter were recruited in Philadelphia and New Jersey, through social media, university clinics, and National Stuttering Association (NSA) self-help groups. The participants engaged in a conversational task with a normally fluent speaker (NFS). The cognitive-affective variables (self-perception of stuttering severity, comfort, cognitive effort, anxiety and benefit) were measured using self-report questionnaires completed after each condition. The percent syllables stuttered and total syllables in each condition were also transcribed and analyzed.ResultsFrequency distributions of Likert Scale ratings indicated a slight preference for self-disclosure over non-disclosure, but there was a non-significant difference on the benefit variable for the disclosed and non-disclosed conditions. There were correlations between total syllables produced and percent syllables stuttered and comfort, in the non-disclosed state only. Other findings included non-significant differences for the cognitive-affective variables across conditions.ConclusionFrom the perspective of the person who stutters, self-disclosure at the outset of the communicative interaction did not have a decisive impact on the cognitive-affective or speech variables.     

Understanding the social emotional practices of therapists

Emotions are central to the therapy process and skilful use by therapists of client emotion is an essential catalyst to client change. However, the contribution of emotion to the therapy process and how therapists’ social emotional skills are incorporated into psychological practice is still unclear. Using a statistical method for mapping psychological constructs, therapists’ social emotional skills were transformed into a “map” with three spatial dimensions, which was supported by comparative reliability checks. The nature of social emotional skills was further investigated by administering a Q-Sort of emotional practice items to 47 therapists. Ten highly applicable clusters of social emotional skills across seven style patterns with therapists were identified. Tentative links were drawn between demographic data and both clusters and therapist styles. These findings suggest therapists’ social emotional skills can be organised into meaningful clusters and that therapists can be styled according to their responses across these clusters. Furthermore, gaps identified in the model suggest possible “blind spots” in the literature. The implications of these findings are significant for training and practice.     

小学儿童CVS策略的发展及其对教育的启示

CVS策略是国外不少研究者正深入研究的一种学习策略,关于它的研究得出了许多有价值的结论。本文首先分析了CVS的概念、研究方法和研究意义,然后对当前的研究结论进行了梳理,从五大方面详细分析了小学儿童CVS策略的发展特点,最后又从四个发面提出了这些研究对当前教育的启示。     

Alcohol use among adults in Kenya: Results from the National Non-Communicable Diseases Risk Factor survey, 2015

The aim of this study was to assess the prevalence and correlates of alcohol use among Kenyan adults. We analysed data from the Kenya cross-sectional national Non-Communicable Diseases Risk Factor survey, 2015. The survey sampled 4 469 adults (median age 38.0 years, interquartile range = 23, age range of 18–69 years). Results indicate that 6.7% were hazardous or harmful alcohol users and 12.8% past month binge-drinkers. In adjusted logistic regression analysis, being male, middle aged, belonging to the Luhya or Kalenjin ethic group, tobacco use, and having hypertension increased the odds for hazardous or harmful alcohol use. Socio-demographic and health factors appear to influence risk for hazardous or harmful alcohol use among adults in Kenya.