Publications by authors named "Ruoyi Zhu"

Evaluating items for potential differential item functioning (DIF) is an essential step to ensuring measurement fairness. In this article, we focus on a specific scenario, namely, the continuous response, severely sparse, computerized adaptive testing (CAT). Continuous responses items are growingly used in performance-based tasks because they tend to generate more information than traditional dichotomous items.

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Repeated measure data design has been used extensively in a wide range of fields, such as brain aging or developmental psychology, to answer important research questions exploring relationships between trajectory of change and external variables. In many cases, such data may be collected from multiple study cohorts and harmonized, with the intention of gaining higher statistical power and enhanced external validity. When psychological constructs are measured using survey scales, a fundamental psychometric challenge for data harmonization is to create commensurate measures for the constructs of interest across studies.

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Article Synopsis
  • The study aimed to evaluate how accurately cognitive functions are measured in participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI), focusing on those with normal cognition, mild cognitive impairment, and Alzheimer's disease.
  • Using data from participant visits, researchers analyzed scores for memory, executive function, language, and visuospatial skills while calculating the standard errors of measurement for each cognitive domain.
  • Results showed that participants with normal cognition scored the highest, those with mild cognitive impairment scored in the middle, and those with Alzheimer's scored the lowest, with varying measurement precision across cognitive domains, particularly less precise for memory.
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Differential item functioning (DIF) analysis refers to procedures that evaluate whether an item's characteristic differs for different groups of persons after controlling for overall differences in performance. DIF is routinely evaluated as a screening step to ensure items behave the same across groups. Currently, the majority DIF studies focus predominately on unidimensional IRT models, although multidimensional IRT (MIRT) models provide a powerful tool for enriching the information gained in modern assessment.

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