A Conditional Item-Fit Index for Rasch Models

Item Consistency Index: An Item-Fit Index for Cognitive Diagnostic Assessment

An item-fit index is a measure of how accurately a set of item responses can be predicted by the test design model. In a diagnostic assessment where items test student mastery on a cognitive model of skills, such an index is needed to determine the alignment between the item responses and skills that each item is designed to measure. In this study, we introduce the Item Consistency Index (ICI),...

A penalty approach to differential item functioning in Rasch models.

A new diagnostic tool for the identification of differential item functioning (DIF) is proposed. Classical approaches to DIF allow to consider only few subpopulations like ethnic groups when investigating if the solution of items depends on the membership to a subpopulation. We propose an explicit model for differential item functioning that includes a set of variables, containing metric as wel...

Evaluation of global testing procedures for item fit to the Rasch model.

Two types of global testing procedures for item fit to the Rasch model were evaluated using simulation studies. The first type incorporates three tests based on first-order statistics: van den Wollenberg's Q(1) test, Glas's R(1) test, and Andersen's LR test. The second type incorporates three tests based on second-order statistics: van den Wollenberg's Q(2) test, Glas's R(2) test, and a non-par...

A Bayesian Nonparametric Model Fit statistic of Item Response Models

Adjusted Rasch person-fit statistics.

Two frequently used parametric statistics of person-fit with the dichotomous Rasch model (RM) are adjusted and compared to each other and to their original counterparts in terms of power to detect aberrant response patterns in short tests (10, 20, and 30 items). Specifically, the cube root transformation of the mean square for the unweighted person-fit statistic, t, and the standardized likelih...