Publications by authors named "Peter Halpin"

This paper proposes a method for assessing differential item functioning (DIF) in item response theory (IRT) models. The method does not require pre-specification of anchor items, which is its main virtue. It is developed in two main steps: first by showing how DIF can be re-formulated as a problem of outlier detection in IRT-based scaling and then tackling the latter using methods from robust statistics.

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Purpose: To explore the relationship between activity engagement and dyadic illness perceptions of community-dwelling individuals with stroke and their caregivers.

Methods: We performed a secondary analysis on a cross-sectional study encompassing eight rehabilitation settings. Participants were recruited from June to December 2019 via the distribution of flyers, use of admission databases, and direct onsite interactions.

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Objectives: To investigate whether individuals' poststroke activity engagement is associated with their perceptions of stroke, as well as their perceptions of physical and social environment.

Design: Cross-sectional study.

Setting: Participants were recruited from eight rehabilitation settings in Beijing, China.

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Background: School-based programmes, including hearing screening, provide essential preventive services for rural children. However, minimal evidence on screening methodologies, loss to follow-up, and scarcity of specialists for subsequent care compound rural health disparities. We hypothesised telemedicine specialty referral would improve time to follow-up for school hearing screening compared with standard primary care referral.

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This paper presents a machine learning approach to multidimensional item response theory (MIRT), a class of latent factor models that can be used to model and predict student performance from observed assessment data. Inspired by collaborative filtering, we define a general class of models that includes many MIRT models. We discuss the use of penalized joint maximum likelihood to estimate individual models and cross-validation to select the best performing model.

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Relatively little research has addressed whether conceptual frameworks of early learning generalize across different national contexts. This article reports on a cross-country measurement invariance analysis of the International Development and Early Learning Assessment (IDELA). The IDELA is a direct assessment tool for 3- to 6-year-old children, intended to measure Early Literacy, Early Numeracy, Motor, and Social-Emotional development.

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The social combination theory of group problem solving is used to extend existing psychometric models to collaborative settings. A model for pairwise group work is proposed, the implications of the model for assessment design are considered, and its estimation is addressed. The results are illustrated with an empirical example in which dyads work together on a twelfth-grade level mathematics assessment.

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Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Gulf War Illness (GWI) are debilitating diseases with overlapping symptomology and there are currently no validated tests for definitive diagnosis of either syndrome. While there is evidence supporting the premise that some herpesviruses may act as possible triggers of ME/CFS, the involvement of herpesviruses in the pathophysiology of GWI has not been studied in spite of a higher prevalence of ME/CFS in these patients. We have previously demonstrated that the deoxyuridine triphosphate nucleotidohydrolases (dUTPase) encoded by Epstein-Barr virus (EBV), human herpesvirus-6 (HHV-6), and varicella-zoster virus (VZV) possess novel functions in innate and adaptive immunity.

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Improving children's learning and development in conflict-affected countries is critically important for breaking the intergenerational transmission of violence and poverty. Yet there is currently a stunning lack of rigorous evidence as to whether and how programs to improve learning and development in conflict-affected countries actually work to bolster children's academic learning and socioemotional development. This study tests a theory of change derived from the fields of developmental psychopathology and social ecology about how a school-based universal socioemotional learning program, the International Rescue Committee's Learning to Read in a Healing Classroom (LRHC), impacts children's learning and development.

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Recent research has demonstrated that perceptual ratings aggregated across multiple non-expert listeners can reveal gradient degrees of contrast between sounds that listeners might transcribe identically. Aggregated ratings have been found to correlate strongly with acoustic gold standard measures both when individual raters use a continuous rating scale such as visual analog scaling (Munson et al., 2012) and when individual raters provide binary ratings (McAllister Byun, Halpin, & Szeredi, 2015).

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Background: Maintaining an external direction of focus during practice is reported to facilitate acquisition of non-speech motor skills, but it is not known whether these findings also apply to treatment for speech errors. This question has particular relevance for treatment incorporating visual biofeedback, where clinician cueing can direct the learner's attention either internally (i.e.

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Transfection of transgenes into Drosophila cultured cells is a standard approach for studying gene function. However, the number of transgenes present in the cell following transient transfection or stable random integration varies, and the resulting differences in expression level affect interpretation. Here we developed a system for Drosophila cell lines that allows selection of cells with a single-copy transgene inserted at a specific genomic site using recombination-mediated cassette exchange (RMCE).

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Unlabelled: Blinded listener ratings are essential for valid assessment of interventions for speech disorders, but collecting these ratings can be time-intensive and costly. This study evaluated the validity of speech ratings obtained through online crowdsourcing, a potentially more efficient approach. 100 words from children with /r/ misarticulation were electronically presented for binary rating by 35 phonetically trained listeners and 205 naïve listeners recruited through the Amazon Mechanical Turk (AMT) crowdsourcing platform.

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We apply the Hawkes process to the analysis of dyadic interaction. The Hawkes process is applicable to excitatory interactions, wherein the actions of each individual increase the probability of further actions in the near future. We consider the representation of the Hawkes process both as a conditional intensity function and as a cluster Poisson process.

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We examined and contrasted 129 Canadian-born and immigrant women's experiences of violence and associated structural and interpersonal factors within indoor commercial sex venues. The majority experienced at least one form of structural, interpersonal, or both types of violence, with the attempted removal of a condom during sexual services being cited most frequently. Canadian-born women reported more frequent violent assaults in the survey data.

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The relationship between linear factor models and latent profile models is addressed within the context of maximum likelihood estimation based on the joint distribution of the manifest variables. Although the two models are well known to imply equivalent covariance decompositions, in general they do not yield equivalent estimates of the unconditional covariances. In particular, a 2-class latent profile model with Gaussian components underestimates the observed covariances but not the variances, when the data are consistent with a unidimensional Gaussian factor model.

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A method for selecting between K-dimensional linear factor models and (K + 1)-class latent profile models is proposed. In particular, it is shown that the conditional covariances of observed variables are constant under factor models but nonlinear functions of the conditioning variable under latent profile models. The performance of a convenient inferential method suggested by the main result is examined via data simulation and is shown to have acceptable error rate control when deciding between the 2 types of models.

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Background: A substantial challenge in addressing adolescent tobacco use is that smoking behaviors occur in complex environments that involve the school setting and larger community context.

Purpose: This study provides an integrated description of factors from the school and community environment that affect youth smoking and explains variation in individual smoking behaviors both within and across schools/communities.

Methods: Data were collected from 82 randomly sampled secondary schools in five Canadian provinces (British Columbia, Manitoba, Ontario, Quebec, Newfoundland, and Labrador) during the 2003-2004 school year.

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Introduction: School characteristics may account for some of the variation in smoking prevalence among schools. The purpose of this study was to investigate the relationships between characteristics of school tobacco policies and school smoking prevalence. We also examined the relationship between these characteristics and individual smoking status.

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The application of statistical testing in psychological research over the period of 1940-1960 is examined in order to address psychologists' reconciliation of the extant controversy between the Fisher and Neyman-Pearson approaches. Textbooks of psychological statistics and the psychological journal literature are reviewed to examine the presence of what Gigerenzer (1993) called a hybrid model of statistical testing. Such a model is present in the textbooks, although the mathematically incomplete character of this model precludes the appearance of a similarly hybridized approach to statistical testing in the research literature.

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