Response style, one common aberrancy in non-cognitive assessments in psychological fields, is problematic in terms of inaccurate estimation of item and person parameters, which leads to serious reliability, validity, and fairness issues (Baumgartner & Steenkamp, 2001; Bolt & Johnson, 2009; Bolt & Newton, 2011). Response style refers to…

Measurement invariance is crucial for an effective and valid measure of a construct. Invariance holds when the latent trait varies consistently across subgroups; in other words, the mean differences among subgroups are only due to true latent ability differences. Differential item functioning (DIF) occurs when measurement invariance is violated.…

Item response functions of the parametric logistic IRT models follow the logistic form which is monotonically increasing. However, item response functions of some real items are nonmonotonic which might lead to examinees with lower proficiency levels receiving higher scores. This study compared three nonparametric IRF estimation methods--the…