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Children differ in their sensitivity to positive and negative environmental influences, which can be measured with the Highly Sensitive Child (HSC) scale. The present study introduces the HSC-21, an adaptation of the original 12 item scale with new items and factor structure that are meant to be more informative than the original ones. The psychometric properties of the HSC-21 were investigated in 1,088 children across Belgium and the Netherlands, including child and mother reports. Results showed evidence for (a) bifactor model with a general sensitivity factor and two specific factors (i.e., Ease of Excitation-Low Sensory Threshold and Aesthetic Sensitivity); (b) (partial) measurement invariance across gender, developmental stage, country, and informants; (c) moderate child-mother agreement; (d) good reliability; (e) normally distributed item scores; and (f) meaningful associations with personality and temperament across both samples. No evidence was found for HSC-21 as a moderator in the relationship between parenting and problem behaviors. ispartof: Assessment vol:29 issue:4 pages:1-23 ispartof: location:United States status: Published online

Massive open online courses (MOOCs) generate learners' performance data that can be used to understand learners' proficiency and to improve their efficiency. However, the approaches currently used, such as assessing the proportion of correct responses in assessments, are oversimplified and may lead to poor conclusions and decisions because they do not account for additional information on learner, content, and context. There is a need for theoretically grounded data-driven explainable educational measurement approaches for MOOCs. In this conceptual paper, we try to establish a connection between psychometrics, a scientific discipline concerned with techniques for educational and psychological measurement, and MOOCs. First, we describe general principles of traditional measurement of learners' proficiency in education. Second, we discuss qualities of MOOCs which hamper direct application of approaches based on these general principles. Third, we discuss recent developments in measuring proficiency that may be relevant for analyzing MOOC data. Finally, we draw directions in psychometric modeling that might be interesting for future MOOC research. ispartof: PSYCHOLOGICA BELGICA vol:60 issue:1 pages:115-131 ispartof: location:England status: published

The methodology of single-case experimental designs (SCED) has been expanding its efforts toward rigorous design tactics to address a variety of research questions related to intervention effective...

In meta-analysis, study participants are nested within studies, leading to a multilevel data structure. The traditional random effects model can be considered as amodel with a randomstudy effect, but additional random effects can be added in order to account for dependent effects sizes within or across studies. The goal of this systematic review is three-fold. First, we will describe how multilevel models with multiple random effects (i.e., hierarchical three-, four-, five-level models and cross-classified random effects models) are applied in meta-analysis. Second, we will illustrate how in some specific three-level meta-analyses, a more sophisticated model could have been used to deal with additional dependencies in the data. Third and last, we will describe the distribution of the characteristics of multilevel meta-analyses (e.g., distribution of the number of outcomes across studies or which dependencies are typically modeled) so that future simulation studies can simulate more realistic conditions. Results showed that four- or five-level or cross-classified randomeffects models are not often used although theymight account better for the meta-analytic data structure of the analyzed datasets. Also, we found that the simulation studies done on multilevel metaanalysis with multiple random factors could have used more realistic simulation factor conditions. The implications of these results are discussed, and further suggestions are given. ispartof: Behavior Research Methods vol:52 issue:5 pages:2031-2052 ispartof: location:United States status: published

The focus of the current study is on handling the dependence among multiple regression coefficients representing the treatment effects when meta-analyzing data from single-case experimental studies. We compare the results when applying three different multilevel meta-analytic models (i.e., a univariate multilevel model avoiding the dependence, a multivariate multilevel model ignoring covariance at higher levels, and a multivariate multilevel model modeling the existing covariance) to deal with the dependent effect sizes. The results indicate better estimates of the overall treatment effects and variance components when a multivariate multilevel model is applied, independent of modeling or ignoring the existing covariance. These findings confirm the robustness of multilevel modeling to misspecifying the existing covariance at the case and study level in terms of estimating the overall treatment effects and variance components. The results also show that the overall treatment effect estimates are unbiased regardless of the underlying model, but the between-case and between-study variance components are biased in certain conditions. In addition, the between-study variance estimates are particularly biased when the number of studies is smaller than 40 (i.e., 10 or 20) and the true value of the between-case variance is relatively large (i.e., 8). The observed bias is larger for the between-case variance estimates compared to the between-study variance estimates when the true between-case variance is relatively small (i.e., 0.5). ispartof: BEHAVIOR RESEARCH METHODS vol:52 issue:5 pages:2008-2019 ispartof: location:United States status: published

Not much is known regarding underlying biological pathways to adolescents' loneliness. Insight in underlying molecular mechanisms could inform intervention efforts aimed at reducing loneliness. Using latent growth curve modeling, baseline levels and development of loneliness were studied in two longitudinal adolescent samples. Genes (OXTR, OXT, AVPR1A, AVPR1B) were examined using SNP-based, gene-based, and polygenic risk score (PRS) approaches. In both samples, SNP- and gene-based tests showed involvement of the OXTR gene in development of loneliness, though, significance levels did not survive correction for multiple testing. The PRS approach provided no evidence for relations with loneliness. We recommend alternative phenotyping methods, including environmental factors, to consider epigenetic studies, and to examine possible endophenotypes in relation to adolescents' loneliness. ispartof: Journal Of Research On Adolescence vol:30 issue:S2 pages:333-348 ispartof: location:United States status: published

Adolescents differ in their degree of Environmental Sensitivity, that is, the ability to perceive and process information about their environment. The present study aimed to investigate the psychometric properties of the Highly Sensitive Child scale (HSC), a self-report measure of Environmental Sensitivity, in two Belgian and UK samples with a total of 3056 adolescents. First, the factor structure, internal consistency, dimensionality, and construct validity of the HSC scale were examined. Second, measurement invariance of the HSC scale across developmental stage, gender, and country was tested. Results supported a bifactor model with a general sensitivity factor and three group factors: Ease of Excitation (EOE), Low Sensory Threshold (LST), and Aesthetic Sensitivity (AES). Cronbach’s alpha and McDonalds’s (hierarchical) omega indicated that the HSC scale is a reliable measure of Environmental Sensitivity, except for AES. Furthermore, AES was associated with different personality traits than EOE and LST. Second, the HSC scale was partially measurement invariant across developmental stage, gender, and country. The results provide important insights in the psychometrics of a first measurement of Environmental Sensitivity in early to late adolescents. Implications for further research are discussed. ispartof: Current Psychology vol:40 issue:7 pages:3309-3325 status: published

Objectives: This study used a two-wave design to examine whether (dis)agreement between mothers and adolescents and between fathers and adolescents in reports of on parenting (i.e., support, proactive control, punishment, harsh punishment, and psychological control) was associated with adolescent Externalizing Problem Behavior (EPB; i.e., aggression and rule-breaking behavior) 1 year later. Methods: Adolescents (N = 1,116, Mage = 13.79) reported on EPB and parenting across both parents, whereas mothers (N = 841) and fathers (N = 724) reported on EPB and their own parenting. As suggested by Laird and De Los Reyes (2013), we used moderated polynomial regressions to investigate informant discrepancy. Results: Results indicated that agreement between mothers and adolescents concerning psychological control positively predicted EPB. Furthermore, there were linear and curvilinear associations between adolescent-reported parenting and EPB. Conclusions: Our findings indicated that the inclusion of multiple informants, and more specifically, the agreement between two informants was important in predicting adolescent problem behavior. Furthermore, it provided support for including both mothers and fathers in future research or clinical programs. Finally, the link between some parenting practices and externalizing problem behavior may be more complex than suggested by previous studies. Concerning clinical implications, the present study provides support for tailoring prevention/intervention programs for the different members of the family.

Research has indicated that a strictly dimensional or parental style approach does not capture the full complexity of parenting. To better understand this complexity, the current study combined these two approaches using a novel statistical technique, i.e., subspace K-means clustering. Four objectives were addressed. First, the study tried to identify meaningful groups of parents in longitudinal adolescent reports on parenting behaviour. Second, the dimensional structure of every cluster was inspected to uncover differences in parenting between and within clusters. Third, the parenting styles were compared on several adolescent characteristics. Fourth, to examine the impact of change in parenting style over time, we looked at the cluster membership over time. Longitudinal questionnaire data were collected at three annual waves, with 1,116 adolescents (mean age = 13.79 years) at wave 1. Based on five parenting dimensions (support and proactive, punitive, psychological and harsh control), subspace K-means clustering, analysed per wave separately, identified two clusters (authoritative and authoritarian parenting) in which parenting dimensions were interrelated differently. Authoritative parenting seemed to be beneficial for adolescent development (less externalising problem behaviour and higher self-concept). Longitudinal data revealed several parenting group trajectories which showed differential relations with adolescent outcomes. Change in membership from the authoritative cluster to the authoritarian cluster was associated with a decrease in self-concept and an increase in externalising problem behaviour, whereas changes from the authoritarian cluster to the authoritative cluster were associated with an increase in self-concept and a decrease in externalising problem behaviour. ispartof: European Child and Adolescent Psychiatry vol:29 issue:3 pages:327-342 ispartof: location:Germany status: published

© 2018, Psychonomic Society, Inc. Electronic learning systems have received increasing attention because they are easily accessible to many students and are capable of personalizing the learning environment in response to students’ learning needs. To that end, using fast and flexible algorithms that keep track of the students’ ability change in real time is desirable. Recently, the Elo rating system (ERS) has been applied and studied in both research and practical settings (Brinkhuis & Maris, 2009; Klinkenberg, Straatemeier, & van der Maas in Computers & Education, 57, 1813–1824, 2011). However, such adaptive algorithms face the cold-start problem, defined as the problem that the system does not know a new student’s ability level at the beginning of the learning stage. The cold-start problem may also occur when a student leaves the e-learning system for a while and returns (i.e., a between-session period). Because external effects could influence the student’s ability level during the period, there is again much uncertainty about ability level. To address these practical concerns, in this study we propose alternative approaches to cold-start issues in the context of the e-learning environment. Particularly, we propose making the ERS more efficient by using an explanatory item response theory modeling to estimate students’ ability levels on the basis of their background information and past trajectories of learning. A simulation study was conducted under various conditions, and the results showed that the proposed approach substantially reduces ability estimation errors. We illustrate the approach using real data from a popular learning platform. ispartof: Behavior Research Methods vol:51 issue:2 pages:895-909 ispartof: location:United States status: published

Objectives Adolescents face multiple changes in their social environment, which makes them more vulnerable to developing internalizing problems with strong interpersonal components, such as feelings of loneliness, social anxiety, and depressive symptoms. Given the widespread tacit assumption that these internalizing problems represent distinct concepts, research on these internalizing problems has evolved relatively independently. However, this assumption of distinctiveness has not often been empirically tested, especially not in adolescence. In order to check whether it is valid to examine loneliness, social anxiety, and depressive symptoms independently, the current study empirically tested whether these internalizing problems reflect a single latent construct or whether they are better represented by three distinct latent constructs. Methods Three large samples of Flemish adolescents were used (i.e., N= 549, Mage = 14.82 in Sample 1; N= 1,116, Mage = 13.79, in Sample 2, and N= 1,423, Mage = 13.58 in Sample 3) in which adolescents filled out well-established and validated self-report questionnaires tapping into the three types of internalizing problems. Confirmatory factor analysis was conducted in each sample separately. Adolescents filled out well-established and validated self-report questionnaires. Results The results contribute to the literature on the co-occurrence of loneliness, social anxiety, and depressive symptoms by showing that these internalizing problems can be best represented as interrelated, but distinguishable constructs. Conclusions Based on our findings, examining loneliness, social anxiety, and depressive symptoms in separate research lines seems justified. Statistical techniques examining co-development over time for these internalizing problems can be used with confidence in future research. ispartof: Journal of Child and Family Studies vol:28 issue:5 pages:1-11 status: Published online

Research on memory reconsolidation has been booming in the last two decades, with numerous high-impact publications reporting promising amnestic interventions in rodents and humans. However, our own recently-published failed replication attempts of reactivation-dependent amnesia for fear memories in rats suggest that such amnestic effects are not always readily found and that they depend on subtle and possibly uncontrollable parameters. The discrepancy between our observations and published studies in rodents suggests that the literature in this field might be biased. The aim of the current study was to gauge the presence of publication bias in a well-delineated part of the reconsolidation literature. To this end, we performed a systematic review of the literature on reactivation-dependent amnesia for contextual fear memories in rodents, followed by a statistical assessment of publication bias in this sample. In addition, relevant researchers were contacted for unpublished results, which were included in the current analyses. The obtained results support the presence of publication bias, suggesting that the literature provides an overly optimistic overall estimate of the size and reproducibility of amnestic effects. Reactivation-dependent amnesia for contextual fear memories in rodents is thus less robust than what is projected by the literature. The moderate success of clinical studies may be in line with this conclusion, rather than reflecting translational issues. For the field to evolve, replication and non-biased publication of obtained results are essential. A set of tools that can create opportunities to increase transparency, reproducibility and credibility of research findings is provided. Fil: Schroyens, Natalie. Katholikie Universiteit Leuven; Bélgica. Leuven Brain Institute; Bélgica Fil: Sigwald D'alesio, Eric Luca. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; Argentina. Katholikie Universiteit Leuven; Bélgica Fil: Van Den Noortgate, Wim. Katholikie Universiteit Leuven; Bélgica Fil: Beckers, Tom. Katholikie Universiteit Leuven; Bélgica. Leuven Brain Institute; Bélgica Fil: Luyten, Laura. Leuven Brain Institute; Bélgica. Katholikie Universiteit Leuven; Bélgica

Cognitive load plays an important role during learning and working, as it has been linked to well-functioning cognitive processes, performance, burnout and depression. Nonetheless, attempts to assess cognitive load in real-time by means of physiological data have been proven difficult, and interpreting these data remains challenging. The aim of this study is to examine whether and how well experienced cognitive load can be measured through psycho-physiological data. The approach of this study is rather unique, for a combination of reasons. First, this study takes a multimodal approach, monitoring EDA (electrodermal activity), EEG (electroencephalography) and EOG (electrooculography). Second, this study is based on a relatively intensive data collection (N = 46) in a controlled lab setting in which varying cognitive load levels are deliberately induced. Finally, not only focussing on statistical significance but also on the size of the association gives insights into how suitable physiological markers are to measure cognitive load. Results from a multilevel analysis suggest that the following physiological markers might be related to cognitive load, for example, in an industrial context: the rate and the duration of skin conductance responses, the alpha power, the alpha peak frequency and the eye blink rate. About 22.8% of the variance in self-reported cognitive load can be explained using these five measures.

In meta-analysis, primary studies often include multiple, dependent effect sizes. Several methods address this dependency, such as the multivariate approach, three-level models, and the robust variance estimation (RVE) method. As for today, most simulation studies that explore the performance of these methods have focused on the estimation of the overall effect size. However, researchers are sometimes interested in obtaining separate effect size estimates for different types of outcomes. A recent simulation study (Park & Beretvas, 2019) has compared the performance of the three-level approach and the RVE method in estimating outcome-specific effects when several effect sizes are reported for different types of outcomes within studies. The goal of this paper is to extend that study by incorporating additional simulation conditions and by exploring the performance of additional models, such as the multivariate model, a three-level model that specifies different study-effects for each type of outcome, a three-level model that specifies a common study-effect for all outcomes, and separate three-level models for each type of outcome. Additionally, we also tested whether the a posteriori application of the RV correction improves the standard error estimates and the 95% confidence intervals. Results show that the application of separate three-level models for each type of outcome is the only approach that consistently gives adequate standard error estimates. Also, the a posteriori application of the RV correction results in correct 95% confidence intervals in all models, even if they are misspecified, meaning that Type I error rate is adequate when the RV correction is implemented. ispartof: BEHAVIOR RESEARCH METHODS vol:53 issue:2 pages:702-717 ispartof: location:United States status: published

The relationships between children with severe or profound intellectual disabilities (ID) and their parents may fulfil attachment functions, such as regulating emotional responses to stress. This study examined the extent to which children with severe or profound ID differentiate between their parents and a stranger as a resource for stress-regulation. A home-based experimental paradigm was conducted and video-recorded in 38 families. Children (1–8 years) were exposed to four naturalistic stressors followed by comfort, randomly provided by the parents or the stranger. Emotional behaviour (arousal and valence) and the skin conductance level were simultaneously recorded. With regard to both emotional behaviour and skin conductance, children significantly differentiated between their parents as attachment figures and the stranger during stress and comfort, despite their impairments on various developmental domains. Behavioural observation and physiology show complementary manifestations of parent-child attachment in this population. ispartof: Attachment & Human Development vol:22 issue:4 pages:425-447 ispartof: location:England status: published

Previous research has introduced several effect size measures (ESMs) to quantify data aspects of single-case experimental designs (SCEDs): level, trend, variability, overlap, and immediacy. In the current article, we extend the existing literature by introducing two methods for quantifying consistency in single-case A-B-A-B phase designs. The first method assesses the consistency of data patterns across phases implementing the same condition, called CONsistency of DAta Patterns (CONDAP). The second measure assesses the consistency of the five other data aspects when changing from baseline to experimental phase, called CONsistency of the EFFects (CONEFF). We illustrate the calculation of both measures for four A-B-A-B phase designs from published literature and demonstrate how CONDAP and CONEFF can supplement visual analysis of SCED data. Finally, we discuss directions for future research. ispartof: Behavior Modification vol:44 issue:4 pages:518-551 ispartof: location:United States status: published

INTRODUCTION: Empathy consists of a cognitive and an affective component, of which it is thought that there are gender differences. Previous studies also suggest that maternal and paternal support play a more prominent role in the development of an adolescent's affective and cognitive empathy, respectively. Besides the environmental factor, that is parenting, adolescent personality, and more specifically, agreeableness, is closely linked to both empathy and support, but this interplay was not extensively investigated longitudinally. The present study investigated the transactional associations among parental support, adolescent agreeableness, and adolescent empathy. More specifically, we examined (a) whether maternal/paternal support is differentially associated with cognitive/affective empathy, while taking into account adolescent agreeableness and (b) whether adolescent agreeableness still predicts empathy, while taking into account parental support. METHODS: Data from 993 Belgian adolescents (MageT1 = 13.96 years; [12.6-18.4]) and their parents across four time points were used in a random intercept cross-lagged panel model. RESULTS: At the between-person level, maternal support was associated with affective, but not cognitive empathy, whereas agreeableness was associated with maternal and paternal support as well as with both types of empathy. At the within-person level, affective empathy predicted cognitive empathy one wave later. CONCLUSIONS: At a population level, agreeableness and support are both important in adolescent empathy development with limited evidence for the differential roles of mothers and fathers. Within participants, affective empathy, and not parental support or agreeableness, predicted cognitive empathy. ispartof: JOURNAL OF ADOLESCENCE vol:85 pages:21-31 ispartof: location:England status: published

Background.Social anxiety symptoms (SAS) are among the most common mental health problems during adolescence, and it has been shown that parenting influences the adolescent’s level of social anxiety. In addition, it is now widely assumed that most mental health problems, including social anxiety, originate from a complex interplay between genes and environment. However, to date, gene–environment (G × E) interactions studies in the field of social anxiety remain limited. In this study, we have examined how 274 genes involved in different neurotransmission pathways interact with five aspects of perceived parenting as environmental exposure (i.e., support, proactive control, psychological control, punitive control, and harsh punitive control) to affect SAS during adolescence.Methods.We have applied an analytical technique that allows studying genetic information at the gene level, by aggregating data from multiple single-nucleotide-polymorphisms within the same gene and by taking into account the linkage disequilibrium structure of the gene. All participants were part of the STRATEGIES cohort of 948 Flemish adolescents (mean age = 13.7), a population-based study on the development of problem behaviors in adolescence. Relevant genes were preselected based on prior findings and neurotransmitter-related functional protein networks.Results.The results suggest that genes involved in glutamate (SLC1A1), glutathione neurotransmission (GSTZ1), and oxidative stress (CALCRL), in association with harsh punitive parenting, may contribute to social anxiety in adolescence. Isolated polymorphisms in these genes have been related to anxiety and related disorders in earlier work.Conclusions: Taken together, these findings provide new insights into possible biological pathways and environmental risk factors involved in the etiology of social anxiety symptoms’ development.Conclusions.Taken together, these findings provide new insights into possible biological pathways and environmental risk factors involved in the etiology of social anxiety symptoms’ development.

The development of divergent thinking (DT) in school-age children and adolescents has received considerable attention in the educational psychology literature since the 1970s. A body of research has outlined the existence of slumps (i.e., temporary declines) in this development with, however, conflicting findings concerning the magnitude and timing of these slumps. This study is the first to meta-analyze prior research findings regarding DT development from Grades 1 to 12, with a particular emphasis on the widely controversial fourth-grade slump. A total of 2139 standardized means from 41 studies involving 40,918 subjects were analyzed using a meta-analytic three-level model. The findings showed an overall upward developmental trend of DT across grade levels, with some discontinuities. Specifically, there was no evidence of a general fourth-grade slump; rather, evidences for a seventh-grade slump were found. Moderator analyses indicated that a fourth-grade slump might be observed depending on DT test, task content domain, intellectual giftedness, and country of study. The existence of the seventh-grade slump was also moderated by DT test, task content domain, and gender. Together, this study deciphers a longstanding debate regarding DT development, a prerequisite knowledge to support age-appropriate educational strategies that encourage creativity development. Implications of these findings for creativity research and practice are discussed.

Sexual minority youth report poorer mental health than heterosexual youth. According to the minority stress framework, this results from sexual minority individuals being societally marginalized, which for sexual minority youth may include being poorly integrated in the peer context. A sociometric approach was used to test whether peer relationships, measured broadly as friendship, acceptance, disliking, and bullying relationships, mediated the link between a sexual minority orientation and depressive symptoms in adolescence. Analyses were conducted across three samples from the Netherlands and Belgium (N = 352; N = 1848; N = 263). Sexual minority respondents reported higher levels of depressive symptoms than heterosexual respondents, yet sexual orientation differences in peer relationships were small. Moreover, no link between peer relationships and depressive symptoms was found. Consequently, indirect effects were small too.

Massive open online courses (MOOCs) are increasingly popular among students of various ages and at universities around the world. The main aim of a MOOC is growth in students’ proficiency. That is why students, professors, and universities are interested in the accurate measurement of growth. Traditional psychometric approaches based on item response theory (IRT) assume that a student’s proficiency is constant over time, and therefore are not well suited for measuring growth. In this study we sought to go beyond this assumption, by (a) proposing to measure two components of growth in proficiency in MOOCs; (b) applying this idea in two dynamic extensions of the most common IRT model, the Rasch model; (c) illustrating these extensions through analyses of logged data from three MOOCs; and (d) checking the quality of the extensions using a cross-validation procedure. We found that proficiency grows both across whole courses and within learning objectives. In addition, our dynamic extensions fit the data better than does the original Rasch model, and both extensions performed well, with an average accuracy of .763 in predicting students’ responses from real MOOCs. ispartof: Behavior Research Methods vol:51 issue:1 pages:332-341 ispartof: location:United States status: published

BACKGROUND: When developmental disabilities researchers use multiple-baseline designs they are encouraged to delay the start of an intervention until the baseline stabilizes or until preceding cases have responded to intervention. Using ongoing visual analyses to guide the timing of the start of the intervention can help to resolve potential ambiguities in the graphical display; however, these forms of response-guided experimentation have been criticized as a potential source of bias in treatment effect estimation and inference. AIMS AND METHODS: Monte Carlo simulations were used to examine the bias and precision of average treatment effect estimates obtained from multilevel models of four-case multiple-baseline studies with series lengths that varied from 19 to 49 observations per case. We varied the size of the average treatment effect, the factors used to guide intervention decisions (baseline stability, response to intervention, both, or neither), and whether the ongoing analysis was masked or not. RESULTS: None of the methods of responding to the data led to appreciable bias in the treatment effect estimates. Furthermore, as timing-of-intervention decisions became responsive to more factors, baselines became longer and treatment effect estimates became more precise. CONCLUSIONS: Although the study was conducted under limited conditions, the response-guided practices did not lead to substantial bias. By extending baseline phases they reduced estimation error and thus improved the treatment effect estimates obtained from multilevel models. ispartof: RESEARCH IN DEVELOPMENTAL DISABILITIES vol:79 pages:77-87 ispartof: location:United States status: published

This paper presents a review of the literature on the measurement of creativity. Creativity definitions are discussed as a starting point for understanding the nature of this con-struct. The four major approaches to measuring creativity (process, person, product and press) are reviewed, pointing out commonly used instruments as well as the advantages and weaknesses of each approach. This review reveals that the measurement of creativity is an unsettled issue, and that the existing instruments purporting to measure creativity suffer from serious conceptual and psychometric shortcomings. Research gaps and suggestions for future research are discussed. ispartof: Creativity. Theories-Research-Applications vol:4 issue:2 pages:238-275 status: published

This paper presents a unilevel and multilevel approach for the analysis and meta-analysis of single-case experiments (SCEs). We propose a definition of SCEs and derive the specific features of SCEs’ data that have to be taken into account when analyzing and meta-analyzing SCEs. We discuss multilevel models of increasing complexity and propose alternative and complementary techniques based on probability combining and randomization test wrapping. The proposed techniques are demonstrated with real-life data and corresponding R code. ispartof: Brain Impairment vol:19 issue:1 pages:33-58 status: published

Deze studie onderzocht hoe leerkracht-leerlingrelaties, peerstatus, en gedragsmatige betrokkenheid onderling samenhangen in het secundair onderwijs. Hierbij werd er onderscheid gemaakt tussen een positieve en negatieve dimensie in de leerkracht-leerlingrelatie en tussen twee aspecten van peerstatus, namelijk acceptatie en populariteit. De onderzoeksgroep bestond uit 1116 Vlaamse adolescenten uit het eerste, tweede, en derde leerjaar van het secundair onderwijs. Tijdens jaarlijkse metingen werden peernominaties van leerkracht-leerlingrelaties en peerstatus, en zelfrapportages van gedragsmatige betrokkenheid afgenomen. Uit cross-lagged analyses bleek dat positieve leerkracht-leerlingrelaties meer betrokkenheid en negatieve leerkracht-leerlingrelaties minder betrokkenheid voorspelden over de tijd. Daarnaast hingen zowel acceptatie als populariteit in de peergroep negatief samen met latere gedragsmatige betrokkenheid. Gedragsmatige betrokkenheid was niet voorspellend voor leerkracht-leerlingrelaties of peerstatus. Resultaten toonden aan dat relaties met leerkrachten en leeftijdsgenoten onafhankelijk van elkaar een belangrijke rol spelen in de ontwikkeling van gedragsmatige betrokkenheid van adolescenten. ispartof: Kind en Adolescent vol:38 issue:3 pages:148-167 status: published

Research on peer-related loneliness in adolescence has paid insufficient attention to the distinction between intimate loneliness (i.e., in a dyadic relationship with a friend) and relational loneliness (i.e., in the broader peer group). This study examined the correlations among a broad set of loneliness scales. A sample of adolescents from Belgium (n = 282; 60% female) completed 8 subscales of 6 established loneliness measures. Results revealed high correlations among these measures. At the same time, confirmatory factor analysis revealed the two expected factors, reflecting intimate and relational loneliness. Furthermore, it was found that boys experienced on average more intimate loneliness than girls, and girls experienced on average more relational loneliness than boys. As different types of loneliness are related to problems in different domains, and adolescents may experience one type of loneliness but not the other, it is essential to know which loneliness measure taps into which type of loneliness. The present study not only provides evidence for the distinction between intimate and relational loneliness, but also shows which type is covered by which of six commonly used loneliness measures. Based on these findings, researchers can now make a more deliberate selection of scales for future research, and can better interpret and integrate findings from previous studies that used different loneliness measures. ispartof: Journal of Child and Family Studies vol:26 issue:8 pages:2059-2069 status: published

© 2017 Elsevier Ltd Background Progress in diagnostic assessment made it possible to diagnose ASD at a young age. Concurrently, intervention research for toddlers with ASD has increased since the past decade. Method In this study, we report on a five-level meta-analysis of 34 single-subject experimental studies, intended to offer a better insight into what types of interventions are effective for toddlers under the age of three with or at risk for ASD. Results The analysis revealed a significant positive overall effect size. We found that interventions at home were significantly more effective compared to those in other settings. Other significant moderators regarding intervention characteristics were the agent of intervention and duration in weeks. No moderator effects of study and child characteristics were found. Conclusions On average, interventions for toddlers with or at risk for ASD are successful. publisher: Elsevier articletitle: Interventions for toddlers with autism spectrum disorder: A meta-analysis of single-subject experimental studies journaltitle: Research in Autism Spectrum Disorders articlelink: http://dx.doi.org/10.1016/j.rasd.2017.01.010 content_type: article copyright: © 2017 Elsevier Ltd. All rights reserved. ispartof: Research in Autism Spectrum Disorders vol:36 pages:79-92 status: published

This study investigated (1) reciprocal links among parental psychological control, peer rejection, and adolescent externalizing (aggressive and rule-breaking behaviour), and (2) the moderating effect of an adolescent genetic factor (biologically informed polygenic score for dopamine signalling). Three-year longitudinal data from 1,116 adolescents (51% boys; M age = 13.79) and their parents included psychological measures (adolescent-reported psychological control, peer-reported rejection, and parent-reported aggressive and rule-breaking behaviour). Cross-lagged analyses showed bidirectional effects between psychological control and both aggressive and rule-breaking behaviour and a unidirectional effect of peer rejection on both forms of problem behaviour over time. Multigroup structural equation modelling revealed genetic moderation only for rule-breaking behaviour: for adolescents with intermediate levels of dopamine signalling significant environmental effects were present, whereas adolescent effects of rule-breaking behaviour on psychological control were significant for adolescents with both intermediate and high profiles and effects on peer rejection only for adolescents with high dopamine profiles. Statement of contribution What is already known on this subject? Parental psychological control is related to adolescent externalizing problems. Experiencing peer rejection reinforces aggressive and rule-breaking behaviour. Single-gene studies show that dopaminergic genes influence externalizing problems directly or in interaction with the environment. What does this study add? Parental psychological control and adolescent aggressive and rule-breaking behaviour exacerbate one another longitudinally. Longitudinal associations between peer rejection and both subtypes of externalizing behaviour are unidirectional. With a polygenic approach, dopaminergic moderation is present for rule-breaking behaviour only.

This study used a person-centered approach to identify adolescents' peer status profiles and examined how these profiles differed regarding the development of school engagement and loneliness. A sample of 794 adolescents was followed from Grades 7 to 11 (MageWave1 = 13.81 years). Measures included peer nominations of peer status, and student reports of school engagement and peer-related loneliness. Latent class growth analysis identified three profiles: popular-liked, unpopular-disliked, and normative. The popular-liked class revealed the lowest levels of behavioral engagement and loneliness. The unpopular-disliked class had higher levels of behavioral engagement, less steep increases in behavioral disaffection, and showed more loneliness. The normative class revealed moderate trajectories of engagement and loneliness. Moreover, boys and girls differed in their academic and psychosocial development. Implications of the findings for school practitioners are discussed. ispartof: Learning and Individual Differences vol:75 pages:1-14 status: published

This study explored transactional associations among adolescent personality (i.e., conscientiousness, agreeableness), parental control (i.e., proactive, punitive, psychological control), and externalizing problem behavior (i.e., aggressive or rule-breaking behavior). A three-wave longitudinal study across a two-year time span provided questionnaire data from 1,116 adolescents (Mage Wave 1 = 13.79, 51% boys), 841 mothers, and 724 fathers that was used in random intercept cross-lagged panel models. At the between-person level, adolescent personality, parental control, and externalizing problem behavior were significantly associated. Concerning the within-person level, conscientiousness showed reciprocal associations with externalizing problem behavior (negative), with agreeableness (positive) and punitive control (negative). Our findings observed a reciprocity between adolescent personality and externalizing problem behavior, but also suggest a role for parental control in this interplay.

© 2018 Psychonomic Society, Inc. It is common for the primary studies in meta-analyses to report multiple effect sizes, generating dependence among them. Hierarchical three-level models have been proposed as a means to deal with this dependency. Sometimes, however, dependency may be due to multiple random factors, and random factors are not necessarily nested, but rather may be crossed. For instance, effect sizes may belong to different studies, and, at the same time, effect sizes might represent the effects on different outcomes. Cross-classified random-effects models (CCREMs) can be used to model this nonhierarchical dependent structure. In this article, we explore by means of a simulation study the performance of CCREMs in comparison with the use of other meta-analytic models and estimation procedures, including the use of three- and two-level models and robust variance estimation. We also evaluated the performance of CCREMs when the underlying data were generated using a multivariate model. The results indicated that, whereas the quality of fixed-effect estimates is unaffected by any misspecification in the model, the standard error estimates of the mean effect size and of the moderator variables’ effects, as well as the variance component estimates, are biased under some conditions. Applying CCREMs led to unbiased fixed-effect and variance component estimates, outperforming the other models. Even when a CCREM was not used to generate the data, applying the CCREM yielded sound parameter estimates and inferences. ispartof: Behavior Research Methods vol:51 issue:3 pages:1286-1304 ispartof: location:United States status: published

Adaptive learning systems have received an increasing attention as they enable to provide personalized instructions tailored to the behaviors and needs of individual learners. In order to reach this goal, it is desired to have an assessment system, monitoring each learner's ability change in real time. The Elo Rating System (ERS), a popular scoring algorithm for paired competitions, has recently been considered as a fast and flexible method that can assess learning progress in online learning environments. However, it has been argued that a standard ERS may be problematic due to the multidimensional nature of the abilities embedded in learning materials. In order to handle this issue, we propose a system that incorporates a multidimensional item response theory model (MIRT) in the ERS. The basic idea is that instead of updating a single ability parameter from the Rasch model, our method allows a simultaneous update of multiple ability parameters based on a compensatory MIRT model, resulting in a multidimensional extension of the ERS ("M-ERS"). To evaluate the approach, three simulation studies were conducted. Results suggest that the ERS that incorrectly assumes unidimensionality has a seriously lower prediction accuracy compared to the M-ERS. Accounting for both speed and accuracy in M-ERS is shown to perform better than using accuracy data only. An application further illustrates the method using real-life data from a popular educational platform for exercising math skills. ispartof: FRONTIERS IN PSYCHOLOGY vol:10 issue:MAR ispartof: location:Switzerland status: published

Previous studies often assumed that parenting practices are similar across families. This assumption is difficult to hold, especially throughout adolescence, a period of major change for both adolescents and their parents. By combining a person-centered and a variable-centered approach, the present study adds to the literature by identifying trajectory classes in parenting behaviors and assessing their associations with externalizing problem behavior. The study aimed (a) to examine the existence of subgroups with different trajectories for five parenting dimensions (i.e., support, proactive control, punitive control, harsh punitive control, psychological control) in mothers and fathers separately, and (b) to assess whether membership of a subgroup is associated with the development of rule-breaking and aggressive behavior, respectively. The current study used four waves of data, with adolescents’ age ranging from 12 to 18 years. Mothers ( N = 747) and fathers ( N = 645) reported on their own parenting behavior, whereas adolescent ( N = 1,116) reported on externalizing problem behavior. Latent class growth analyses per parenting dimension showed that trajectory classes could be distinguished for support, proactive, punitive, and psychological control, but not harsh punitive control, and this for both mother and father. Conditional growth models per parenting dimension and per parent did not show different trajectories for aggressive and rule-breaking behavior across adolescence for the distinct parenting trajectories. However, analyses indicated that depending on the parenting trajectory, there was a difference in initial (Age 12) levels of problem behavior. Suggestions for additional research on longitudinal heterogeneity of parenting among mothers and fathers of adolescents are outlined. ispartof: Developmental Psychology vol:55 issue:3 pages:653-673 ispartof: location:United States status: published

The Torrance Test of Creative Thinking-Verbal (TTCT-Verbal) is a commonly used measure of creative potential. The present study examined the factor structure, measurement invariance, and latent mean differences across gender, year of study, and academic major for the Arabic version of the TTCT-Verbal. Data were collected among 621 Egyptian undergraduate students. The results supported a bifactor structure for the TTCT-Verbal scores, in which a general divergent thinking factor coexisted alongside six activity-specific factors. Strict invariance was supported for this structure across gender, year of study, and academic major. Latent means were found to significantly differ by year of study, but not by gender or academic major. In contrast, comparisons of observed means showed significant differences by year of study and academic major, but not by gender. Implications of these findings for creativity measurement and development as well as directions for future research are discussed.

This study investigates three methods to handle dependency among effect size estimates in meta-analysis arising from studies reporting multiple outcome measures taken on the same sample. The three-level approach is compared with the method of robust variance estimation, and with averaging effects within studies. A simulation study is performed, and the fixed and random effect estimates of the three methods are compared with each other. Both the robust variance estimation and three-level approach result in unbiased estimates of the fixed effects, corresponding standard errors and variances. Averaging effect sizes results in overestimated standard errors when the effect sizes within studies are truly independent. Although the robust variance and three-level approach are more complicated to use, they have the advantage that they do not require an estimate of the correlation between outcomes, and they still result in unbiased parameter estimates.

This study investigated the effects of student and classroom characteristics on math self-confidence, perceived usefulness, and enjoyment of mathematics as multiple outcomes. A sample of 7th-grade students from 78 classes of 49 schools was studied. The data were collected using, among other instruments, an attitude questionnaire. The results of the multivariate multilevel analysis showed that the variance of the 3 indicators was situated mostly at the student level, and that the indicators correlated strongly at the class level. Higher prior mathematics achievement and positive parental beliefs and attitudes were significant predictors of higher scores across the 3 indicators. Each of the baseline indicators was significantly associated with its corresponding final indicator. At the classroom level, classroom assessment was significantly associated with less endorsement of all 3 indicators, higher levels of classroom modeling with greater endorsement of perceived usefulness of mathematics, and cla...

Interpersonal theories of depression postulate that depressed individuals’ experience of social isolation is attributable, in part, to their tendency to behave in ways that elicit rejection from others. Depression contagion has been implicated as a factor that may account for the rejection of depressed individuals. In the current study, we revisit this hypothesis by using a controlled, but realistically motivated, setting: speed dating. Approximately 2 weeks before the speed-dating event, participants’ depression levels were assessed. During the event, participants had 4-min “dates” with opposite-sex partners. After each date, they responded to items that measured their affect and romantic attraction. At the end of the evening, participants indicated which partners they wanted to see again. Our results did not support depression contagion: After 4 min of interaction with partners with high levels of depressive symptoms, participants did not experience increased negative affect; instead, they experienced reduced positive affect, which led to the rejection of these partners.

This article reports on a Monte Carlo simulation study, evaluating two approaches for testing the intervention effect in replicated randomized AB designs: two-level hierarchical linear modeling (HLM) and using the additive method to combine randomization test p values (RTcombiP). Four factors were manipulated: the mean intervention effect, the number of cases included in a study, the number of measurement occasions for each case, and the between-case variance. Under the simulated conditions, Type I error rate was under control at the nominal 5% level for both HLM and RTcombiP. Furthermore, for both procedures, a larger number of combined cases resulted in higher statistical power, with many realistic conditions reaching statistical power of 80% or higher. Smaller values for the between-case variance resulted in higher power for HLM. A larger number of data points resulted in higher power for RTcombiP. peerreview_statement: The publishing and review policy for this title is described in its Aims & Scope. aims_and_scope_url: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=vjxe20 ispartof: Journal of Experimental Education vol:85 issue:2 pages:175-196 status: published

The impact of misspecifying covariance matrices at the second and the third levels of the three-level model on inferences regarding the overall treatment effect and (co)variances estimates is evaluated by means of a simulation study and an empirical illustration is given. The results indicate that ignoring an existing covariance has no effect on the treatment effect estimate. In addition, the between-case variance estimates are unbiased and well estimated either when covariance is modeled or ignored. If the research interest lies in the between-study variance estimate, including at least 30 studies is warranted to get unbiased and precise estimates. Modeling covariance does not result in less biased and more precise between-study variance estimates as the between-study covariance estimate is extremely biased. As a consequence, single-case researchers can use either the model ignoring or modeling covariance when the research interest lies in the overall treatment effect estimate and/or the between-case variance. In addition, when the research interest lies on the between-case covariance, the model including covariance results in unbiased between-case variance estimates. The three-level model appears to be less appropriate to estimate the between-study variance if less than 30 studies are included. peerreview_statement: The publishing and review policy for this title is described in its Aims & Scope. aims_and_scope_url: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=vjxe20 ispartof: Journal of Experimental Education vol:84 issue:3 pages:473-509 status: published

The Verbal Torrance Test of Creative Thinking (Verbal TTCT) is one of the most frequently used instruments in creativity research. However, its factor structure is still debated and mostly assessed in western contexts. The purpose of the current study was to provide new insights into the factor structure underlying this instrument, with a particular focus on an Arabic context. A sample of 621 undergraduate students from Egypt completed an Arabic version of the Verbal TTCT (Form B). Exploratory and confirmatory factor analyses based on classical test theory were performed, followed by a confirmatory multidimensional item response theory analysis. The findings suggested a novel bifactor structure comprising a general factor in addition to six activity-specific factors. Further support for the bifactor structure was provided by subsequent analyses of residual correlations, empirical reliability, item fit, and item parameters. Theoretical and applied implications of these findings are discussed. ispartof: Thinking Skills and Creativity vol:35 status: published

Across cultures, intergroup contact – positive interpersonal interaction with out-group members – was found to reduce prejudice. Contact research was criticized, however, for bypassing intergroup (in)equality in the wider society. We propose a cultural psychology approach grounding people’s contact experiences in culturally afforded ways of relating to out-groups. Extending Allport’s (1954) equal-status hypothesis to the culture level we hypothesized that contact would be most effective in egalitarian cultures and less effective in more hierarchical cultures. To test this hypothesis, we revisited Pettigrew and Tropp’s (2005, 2006) influential meta-analysis of contact studies and augmented it with culture-level measures of equality and hierarchy values. Our meta-analysis of intergroup contact and prejudice in 660 original samples across 36 cultures confirmed that egalitarianism predicted more effective contact. Cultural hierarchy values and social-dominance orientation attenuated contact effects. Cultures of (in)equality made a difference over and above equal status in the contact situation. ispartof: Social Psychological and Personality Science vol:9 issue:8 pages:887-895 status: published

The synthesis of standardized regression coefficients is still a controversial issue in the field of meta-analysis. The difficulty lies in the fact that the standardized regression coefficients belonging to regression models that include different sets of covariates do not represent the same parameter, and thus their direct combination is meaningless. In the present study, a new approach called concealed correlations meta-analysis is proposed that allows for using the common information that standardized regression coefficients from different regression models contain to improve the precision of a combined focal standardized regression coefficient estimate. The performance of this new approach was compared with that of two other approaches: (1) carrying out separate meta-analyses for standardized regression coefficients from studies that used the same regression model, and (2) performing a meta-regression on the focal standardized regression coefficients while including an indicator variable as a moderator indicating the regression model to which each standardized regression coefficient belongs. The comparison was done through a simulation study. The results showed that, as expected, the proposed approach led to more accurate estimates of the combined standardized regression coefficients under both random- and fixed-effect models. ispartof: Behavior Research Methods vol:51 issue:1 pages:316-331 ispartof: location:United States status: published

The current article presents a systematic review of consistency in single-case ABAB phase designs. We applied the CONsistency of DAta Patterns (CONDAP) measure to a sample of 460 data sets retrieved from 119 applied studies published over the past 50 years. The main purpose was to (a) identify typical CONDAP values found in published ABAB designs and (b) develop interpretational guidelines for CONDAP to be used for future studies to assess the consistency of data patterns from similar phases. The overall distribution of CONDAP values is right-skewed with several extreme values to the right of the center of the distribution. The B-phase CONDAP values fall within a narrower range than the A-phase CONDAP values. Based on the cumulative distribution of CONDAP values, we offer the following interpretational guidelines in terms of consistency: very high, 0 ≤ CONDAP ≤ 0.5; high, 0.5 < CONDAP ≤ 1; medium, 1 < CONDAP < 1.5; low, 1.5 < CONDAP ≤ 2; very low, CONDAP > 2. We give examples of combining CONDAP benchmarks with visual analysis of single-case ABAB phase designs and conclude that the majority of data patterns (41.2%) in published ABAB phase designs is medium consistent. ispartof: Behavior Modification pages:1-30 status: Published online

When (meta-)analyzing single-case experimental design (SCED) studies by means of hierarchical or multilevel modeling, applied researchers almost exclusively rely on the linear mixed model (LMM). This type of model assumes that the residuals are normally distributed. However, very often SCED studies consider outcomes of a discrete rather than a continuous nature, like counts, percentages or rates. In those cases the normality assumption does not hold. The LMM can be extended into a generalized linear mixed model (GLMM), which can account for the discrete nature of SCED count data. In this simulation study, we look at the effects of misspecifying an LMM for SCED count data simulated according to a GLMM. We compare the performance of a misspecified LMM and of a GLMM in terms of goodness of fit, fixed effect parameter recovery, type I error rate, and power. Because the LMM and the GLMM do not estimate identical fixed effects, we provide a transformation to compare the fixed effect parameter recovery. The results show that, compared to the GLMM, the LMM has worse performance in terms of goodness of fit and power. Performance in terms of fixed effect parameter recovery is equally good for both models, and in terms of type I error rate the LMM performs better than the GLMM. Finally, we provide some guidelines for applied researchers about aspects to consider when using an LMM for analyzing SCED count data. ispartof: Behavior Research Methods vol:51 issue:6 pages:2477-2497 ispartof: location:United States status: published

The classical view of emotion hypothesizes that certain emotion categories have a specific autonomic nervous system (ANS) "fingerprint" that is distinct from other categories. Substantial ANS variation within a category is presumed to be epiphenomenal. The theory of constructed emotion hypothesizes that an emotion category is a population of context-specific, highly variable instances that need not share an ANS fingerprint. Instead, ANS variation within a category is a meaningful part of the nature of emotion. We present a meta-analysis of 202 studies measuring ANS reactivity during lab-based inductions of emotion in nonclinical samples of adults, using a random effects, multilevel meta-analysis and multivariate pattern classification analysis to test our hypotheses. We found increases in mean effect size for 59.4% of ANS variables across emotion categories, but the pattern of effect sizes did not clearly distinguish 1 emotion category from another. We also observed significant variation within emotion categories; heterogeneity accounted for a moderate to substantial percentage (i.e., I2 ≥ 30%) of variability in 54% of these effect sizes. Experimental moderators epiphenomenal to emotion, such as induction type (e.g., films vs. imagery), did not explain a large portion of the variability. Correction for publication bias reduced estimated effect sizes even further, increasing heterogeneity of effect sizes for certain emotion categories. These findings, when considered in the broader empirical literature, are more consistent with population thinking and other principles from evolutionary biology found within the theory of constructed emotion, and offer insights for developing new hypotheses to understand the nature of emotion. (PsycINFO Database Record

© 2016 Taylor & Francis. In this article, multiple-baseline across participants designs were used to evaluate the impact of a precision teaching (PT) program, within a Tier 2 Response to Intervention framework, targeting fluency in foundational reading skills with at risk kindergarten readers. Thirteen multiple-baseline design experiments that included participation from 35 kindergarten students were included in the current analysis. By combining data from a series of multiple-baseline studies using a multilevel model, we analyzed outcomes to determine an estimated treatment effect. The results indicate that across participants and across studies, PT showed an average increase of 15 correct responses in foundational reading skills per minute. This immediate influence on rates of core reading skills was statistically significant. Moreover, the treatment had a significant positive effect on the time trend indicating that rates in foundational reading skills increased more across time during the treatment phase compared to the baseline phase. The study provides evidence that the obtained rates in foundational reading skills at the end of the intervention were retained after removing the intervention. From the outcomes of the multilevel model, PT can be considered as a promising Tier 2 intervention to increase reading fluency with individuals who are at risk of reading failure. ispartof: Exceptionality vol:26 issue:3 pages:137-161 status: published

Loneliness is an adverse phenomenon that tends to peak during adolescence. As loneliness is a subjective state, it is different from the objective state of being alone. People’s attitudes toward being alone can be more or less negative or positive. Cultures differ in the form and meaning of social behavior, interpersonal relationships, and time spent alone. However, for cross-cultural comparisons to be meaningful, measurement invariance of the measure should be established. The present study examined measurement invariance of the Loneliness and Aloneness Scale for Children and Adolescents (LACA) in a sample of 218 Belgian and 190 Chinese early adolescents, aged 11–15 years. Using nested multigroup confirmatory factor analyses, measurement invariance of the LACA across Belgium and China was established. More specifically, evidence was found for configural, metric, and partial scalar invariance. Because partial scalar invariance was established, the two cultural groups could be compared. No significant differences were found for peer-related loneliness. Regarding the attitudes toward aloneness, Belgian adolescents were more negative and less positive toward being alone than Chinese adolescents. The present study is encouraging for researchers who want to use the LACA for cross-cultural comparisons, in that we found evidence for measurement invariance across two disparate cultural groups speaking completely different languages. ispartof: Journal of Child and Family Studies vol:25 issue:5 pages:1408-1415 status: published

Results from single-case studies are being synthesized using three-level models in which repeated observations are nested in participants, which in turn are nested in studies. We examined the performance of these models under conditions in which the errors associated with the repeated observations (the Level-1 errors) were assumed to be first-order autoregressive. Monte Carlo methods were used to examine conditions in which the first-order autoregressive assumption was accurate, conditions in which it represented an overspecification because the errors were actually independent, and conditions in which it represented a misspecification because the errors were generated on the basis of a moving-average model. Conditions also varied the series lengths, the numbers of participants per study, the numbers of studies per meta-analysis, the variances between the participants within studies, and the variances between studies. Fixed effects (e.g., the average treatment effect for the intervention and the average treatment effect for the trend) tended to be unbiased, and confidence intervals for the fixed effects tended to be accurate even when the error covariance model was overspecified or misspecified. The variance components, particularly at Levels 2 and 3, showed substantial bias.

In special education, multilevel models of single-case research have been used as a method of estimating treatment effects over time and across individuals. Although multilevel models can accurately summarize the effect, it is known that if the model is misspecified, inferences about the effects can be biased. Concern with the potential for model misspecification motivates our method for evaluating multilevel models of single-case data. This method is based on the visual analysis of graphs that have the model-implied individual trajectories superimposed on plots of the raw data. Through the reanalysis of a published study, we show how this visual analysis approach can identify model misspecifications and motivate the consideration of alternative model specifications that lead to better fit.

This study extends previous gene-by-environment (G × E) research through design and methodological advances and examines alternative hypotheses of diathesis stress, vantage sensitivity, and differential susceptibility. In a sample of 984 adolescents and their parents, we examined whether effects of parental support, proactive, punitive, harsh punitive, and psychological control on externalizing problem behavior are moderated by adolescents' genotype for the dopamine transporter (DAT1) or receptor D4 (DRD4) gene. Results provided evidence for main effects of parenting behavior and DRD4, and multiple interaction effects of which one survived Bonferroni correction. Adolescents carrying a long DRD4 variant were more susceptible to the effects of parental proactive control on aggression, for better and for worse. Critical considerations were made regarding the complexity of G × E research. ispartof: Journal of Research on Adolescence vol:27 issue:2 pages:278-297 ispartof: location:United States status: published