Efficient nonparametric approaches for estimating the operating characteristics of discrete item responses

Rationale and the actual procedures of two nonparametric approaches, called Bivariate P.D.F. Approach and Conditional P.D.F. Approach, for estimating the operating characteristic of a discrete item response, or the conditional probability, given latent trait, that the examinee's response be that specific response, are introduced and discussed. These methods are featured by the facts that: (a) estimation is made without assuming any mathematical forms, and (b) it is based upon a relatively small sample of several hundred to a few thousand examinees.Some examples of the results obtained by the Simple Sum Procedure and the Differential Weight Procedure of the Conditional P.D.F. Approach are given, using simulated data. The usefulness of these nonparametric methods is also discussed.This research was mostly supported by the Office of Naval Research (N00014-77-C-0360, N00014-81-C-0569, N00014-87-K-0320, N00014-90-J-1456).     

Regression Mixture Models: Does Modeling the Covariance Between Independent Variables and Latent Classes Improve the Results?

Regression mixture models are increasingly used as an exploratory approach to identify heterogeneity in the effects of a predictor on an outcome. In this simulation study, we tested the effects of violating an implicit assumption often made in these models; that is, independent variables in the model are not directly related to latent classes. Results indicate that the major risk of failing to model the relationship between predictor and latent class was an increase in the probability of selecting additional latent classes and biased class proportions. In addition, we tested whether regression mixture models can detect a piecewise relationship between a predictor and outcome. Results suggest that these models are able to detect piecewise relations but only when the relationship between the latent class and the predictor is included in model estimation. We illustrate the implications of making this assumption through a reanalysis of applied data examining heterogeneity in the effects of family resources on academic achievement. We compare previous results (which assumed no relation between independent variables and latent class) to the model where this assumption is lifted. Implications and analytic suggestions for conducting regression mixture based on these findings are noted.     

Dealing with Multiple Solutions in Structural Vector Autoregressive Models

Structural vector autoregressive models (VARs) hold great potential for psychological science, particularly for time series data analysis. They capture the magnitude, direction of influence, and temporal (lagged and contemporaneous) nature of relations among variables. Unified structural equation modeling (uSEM) is an optimal structural VAR instantiation, according to large-scale simulation studies, and it is implemented within an SEM framework. However, little is known about the uniqueness of uSEM results. Thus, the goal of this study was to investigate whether multiple solutions result from uSEM analysis and, if so, to demonstrate ways to select an optimal solution. This was accomplished with two simulated data sets, an empirical data set concerning children's dyadic play, and modifications to the group iterative multiple model estimation (GIMME) program, which implements uSEMs with group- and individual-level relations in a data-driven manner. Results revealed multiple solutions when there were large contemporaneous relations among variables. Results also verified several ways to select the correct solution when the complete solution set was generated, such as the use of cross-validation, maximum standardized residuals, and information criteria. This work has immediate and direct implications for the analysis of time series data and for the inferences drawn from those data concerning human behavior.     

Time-Varying Treatments in Observational Studies: Marginal Structural Models of the Effects of Early Grade Retention on Math Achievement

One of the main objectives of many empirical studies in the social and behavioral sciences is to assess the causal effect of a treatment or intervention on the occurrence of a certain event. The randomized controlled trial is generally considered the gold standard to evaluate such causal effects. However, for ethical or practical reasons, social scientists are often bound to the use of nonexperimental, observational designs. When the treatment and control group are different with regard to variables that are related to the outcome, this may induce the problem of confounding. A variety of statistical techniques, such as regression, matching, and subclassification, is now available and routinely used to adjust for confounding due to measured variables. However, these techniques are not appropriate for dealing with time-varying confounding, which arises in situations where the treatment or intervention can be received at multiple timepoints. In this article, we explain the use of marginal structural models and inverse probability weighting to control for time-varying confounding in observational studies. We illustrate the approach with an empirical example of grade retention effects on mathematics development throughout primary school.     

A Note on Recurring Misconceptions When Fitting Nonlinear Mixed Models

Nonlinear mixed-effects (NLME) models are used when analyzing continuous repeated measures data taken on each of a number of individuals where the focus is on characteristics of complex, nonlinear individual change. Challenges with fitting NLME models and interpreting analytic results have been well documented in the statistical literature. However, parameter estimates as well as fitted functions from NLME analyses in recent articles have been misinterpreted, suggesting the need for clarification of these issues before these misconceptions become fact. These misconceptions arise from the choice of popular estimation algorithms, namely, the first-order linearization method (FO) and Gaussian-Hermite quadrature (GHQ) methods, and how these choices necessarily lead to population-average (PA) or subject-specific (SS) interpretations of model parameters, respectively. These estimation approaches also affect the fitted function for the typical individual, the lack-of-fit of individuals’ predicted trajectories, and vice versa.     

Relational spirituality and depression among married couples in Antigua

The World Health Organization indicates depression is the leading cause of disability worldwide. At the same time researchers have found religion/spirituality is inversely associated with depression. However, the mechanisms by which spirituality/religion impacts mental health have not been clearly identified particularly in non-western populations. Relational spirituality is a concept that focuses attention on the ways people relate to the sacred. This study examines whether different ways of relating to the sacred are implicated in levels of depression and whether marital partners affect each other’s level of relational spirituality and depression. Ninety-one (n?=?91) married heterosexual couples in the Caribbean Island of Antigua completed measures of relational spirituality and depression. Data were analysed using path analysis and through Actor Partner Interdependence Model methods. Results of the analysis showed wives’ and husbands’ depression scores covaried (COV?=?6.59, Pearson r?=?.28, p?β?=??.24, unstandardised B?=??3.23, se?=?1.30), and higher instability scores (β?=?.49, unstandardised B?=?5.46, se?=?.96). The husbands’ disappointment (β?=?.21, unstandardised B?=?2.17, se?=?.95) and instability (β?=?.54, unstandardised B?=?4.65, se?=?.72) were positively related to their depression scores. The results demonstrate relational spirituality is a useful framework for addressing depression in individuals as well as married couples.     

Expertise in soccer teams: A thematic inquiry into the role of Shared Mental Models within team chemistry

AimsThe purpose of the current study was to establish a conceptual framework of team chemistry components in sport with an emphasis on Shared Mental Models (SMM).MethodElite soccer coaches (n = 6) and players (n = 3) were interviewed using a semi-structured interview guide. An inductive thematic analysis was employed to analyze the data.ResultsFour themes related to team chemistry components were identified: (1) members' characteristics (i.e., demographic data, on-field characteristics, and member's ego), (2) coach–players interactions (i.e., professional interaction and emotional intelligence of coaches), (3) interactions among the players (i.e., professional understanding, efficacy beliefs, team cohesion, players' emotional intelligence, team roles, and goals), and (4) interactions with environmental factors (i.e., owners, management, fans, and media).ConclusionsThe cognitive components of the team chemistry model were clustered to establish a conceptual framework of SMM. Furthermore, the cognitive-affective-social-behavioral linkage of team chemistry and athletic performance is examined in light of the emerged model and conceptual framework. Implications and future directions are also discussed.     

Children's and Mothers' Contribution to Joint Reminiscing in Different Sociocultural Contexts: Who Speaks and What is Said

The study compares mothers' conversation with their 4‐year‐old children about two past events in two autonomy‐oriented (35 German and 42 Swedish families), one relatedness‐oriented (22 Cameroonian Nso families) and one autonomy‐relatedness oriented (38 Estonian families) contexts. German mothers were rather similar to Swedish mothers in talking a lot, providing a lot of information and engaging children into conversation, but they differed from Swedish mothers by talking more about social content. Swedish children were more independent conversational partners to their mothers than other children, including German children. Estonian mothers' contribution to conversation was similar to Cameroonian Nso mothers, except that they asked a lot of open‐ended questions to engage children in conversations. Estonian children did not differ from Swedish and German children in their contribution to conversations. Compared to Swedish mothers, past event talk of Estonian mothers was characterized by a bigger proportion of talk devoted to social content, but also to the child, mental states and non‐social content. It was characteristic of Cameroonian Nso mothers that they focused more on other people and actions, and their conversational dominance was larger. Differences in reminiscing were consistent with different cultural models of self and the type of autonomy – psychological or action – promoted. Copyright © 2015 John Wiley & Sons, Ltd.