PURPOSE To further refine the Adult Strabismus 20 (AS-20) health-related quality of life (HRQOL) questionnaire using Rasch analysis. METHODS Rasch analysis was performed independently on the original AS-20 using the following steps: dimensionality, response ordering, local dependence, infit and outfit analyses, differential item functioning, subject targeting, and confirmatory dimensionality....

BACKGROUND The Center for Epidemiologic Studies Depression Scale (CES-D; Radloff, 1977) is a commonly used freely available self-report measure of depressive symptoms. Despite its popularity, several recent investigations have called into question the robustness and suitability of the commonly used 4-factor 20-item CES-D model. The goal of the current study was to address these concerns by conf...

INTRODUCTION The Skin Self-Examination Attitude Scale (SSEAS) is a brief measure that allows for the assessment of attitudes in relation to skin self-examination. This study evaluated the psychometric properties of the SSEAS using Item Response Theory (IRT) methods in a large sample of men ≥ 50 years in Queensland, Australia. METHODS A sample of 831 men (420 intervention and 411 control) comp...

Objective The objective of this study was to report the item response theory (IRT) calibration of an 18-item bank to measure general physical function (GPF) in a wide range of conditions and evaluate the validity of the derived scores. Methods All 18 items were administered to a large sample of patients (n=2337) who responded to the items in the context of their outpatient rehabilitation care...

Item Response Theory (IRT) models were investigated as a tool for student modeling in an intelligent tutoring system (ITS). The models were tested using real data of high school students using the Wayang Outpost, a computer-based tutor for the mathematics portion of the Scholastic Aptitude Test (SAT). A cross-validation framework was developed and three metrics to measure prediction accuracy we...

Recently, adaptive test approaches have become a viable alternative to traditional fixed-item tests. The main advantage of tests is that they reach desired measurement precision with fewer items. However, items mean each item has more significant effect on ability estimation and therefore those are open consequential results from any flaw in an item. So, indicating differential functioning (DIF...

Benefits of physical activity for those with arthritis are clear, yet physical activity is difficult to initiate and maintain. Self-efficacy is a key modifiable psychosocial determinant of physical activity. This study examined two scales for self-efficacy for exercise behavior (SEEB) to identify their strengths and weaknesses using item response theory (IRT) from community-based randomized con...

BACKGROUND Item response theory (IRT) has been increasingly applied to patient-reported outcome (PRO) measures. The purpose of this study is to apply IRT to examine item properties (discrimination and severity of depressive symptoms), measurement precision and score comparability across five depression measures, which is the first study of its kind in the Chinese context. METHODS A clinical s...