OBJECTIVE To develop an item response theory (IRT)-calibrated spinal cord injury (SCI)-specific Positive Affect and Well-being (PAWB) item bank with flexible options for administration. DESIGN Qualitative feedback from patient and provider focus groups was used to expand on the Neurological Disorders and Quality of Life (Neuro-QOL) positive affect & well-being item bank for use in SCI. New it...

Two versions of a normal and lognormal model for the response times of examinees on test items are investigated. The models have a parameter structure analogous to the 2PL response models in IRT, with a parameter for the speed of each person as well as parameters for the time intensity and discriminating power of each item. It is shown how the parameters can be estimated by a Markov chain Monte...

This introduction to the R package plink is a (slightly) modified version of Weeks (2010), published in the Journal of Statistical Software. The R package plink has been developed to facilitate the linking of mixed-format tests for multiple groups under a common item design using unidimensional and multidimensional IRT-based methods. This paper presents the capabilities of the package in the co...

This study aims to examine the effects of mixture item response theory (IRT) models on parameter estimation and classification accuracy under different conditions. The manipulated variables simulation are set as IRT (Rasch, 2PL, 3PL); sample size (600, 1000); number items (10, 30); latent classes (2, 3); missing data type (complete, at random (MAR) not (MNAR)), percentage (10%, 20%). Data were ...

Item response theory (IRT) is an important method of assessing the validity of measurement scales that is underutilized in the field of psychiatry. IRT describes the relationship between a latent trait (e.g., the construct that the scale proposes to assess), the properties of the items in the scale, and respondents' answers to the individual items. This paper introduces the basic premise, assum...

The main purpose of this paper is to examine the psychometric properties of the original five-point CWEQ II using Item Response Theory (IRT) methods, followed by an examination of the revised three-point CWEQ II. (1) Background: The psychometric properties of the CWEQ II have not been previously assessed using more robust techniques such as IRT. (2) Methods: This is a secondary analysis of base...