Two Ph.D. candidates in our Quantitative program have scored a 2025 Psychometric Society Travel Award! Sunbeom Kwon and Trung Le have their fees waived and receive funds to support their travel to the conference.
Kwon's work, which will be presented at the conference, is titled “A copula-based joint model for item responses and response times.” This work proposes a novel methodology that uses copula functions to flexibly model the dependency between item responses and response times. The project aims to improve ability estimation in educational and psychological testing by capturing more accurate and flexible relationships in multivariate data involving latent variables.
Le will be showcasing their work twice during the conference. The award-winning project focuses on using hidden Markov models (HMMs) to evaluate interventions in educational and psychological studies. Specifically, Le wrote mathematical proofs to check for conditions under which the HMMs are identifiable, i.e., when the models provide interpretable and meaningful results. Trung also developed code and software to implement the models and tested them through extensive simulation studies. The second presentation addresses the issue of test fairness through what's called Differential Item Functioning (DIF). Particularly, examining the behavior of the non-compensatory differential item functioning (NCDIF) index and established guidelines for interpreting it as an effect size measure for DIF.