Item response theory (IRT) models are a class of statistical models used by researchers to describe the response behaviors of individuals to a set of categorically scored items. The most common IRT models can be classified as generalized linear fixedand/or mixed-effect models. Although IRT models appear most often in the psychological testing literature, researchers in other fields have success...

Changes in the skin temperature (Tsk) are known to be connected with diseases and subsequently infrared thermography (IRT) has been proposed to be a diagnostic aid, e.g. in musculoskeletal disorders (MSD). However, mostly due to conflicting results of previous studies, IRT lost credibility. Now interest in IRT is growing again but valid methodological studies are needed in order to avoid new di...

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...

CONTEXT Newborn screening for cystic fibrosis (CF) is included in many routine programmes but current strategies have considerable drawbacks, such as false-positive tests, equivocal diagnosis and detection of carriers. OBJECTIVE To assess the test performance of two newborn screening strategies for CF. DESIGN, SETTING AND PARTICIPANTS In 2008 and 2009, CF screening was added to the routine ...

In item response theory (IRT) models, assessing model-data fit is an essential step in IRT calibration. While no general agreement has ever been reached on the best methods or approaches to use for detecting misfit, perhaps the more important comment based upon the research findings is that rarely does the research evaluate IRT misfit by focusing on the practical consequences of misfit. The stu...

This paper applies the techniques of Item Response Theory (IRT) to data from the Statistics Concept Inventory (SCI). Based on results from the Fall 2005 post-test (n = 422 students), the analyses of IRT are compared with those of Classical Test Theory (CTT). The concepts are extended to discussions of other applications, such as computerized adaptive testing and Likertscale items which may be o...

This paper reviews the problems associated with using IRT-based latent variable scores for analytical modeling, discusses the connection between IRT and SEM-based latent regression modelling for discrete data, and compares regression parameter estimates obtained using predicted IRT scores and standardized Number-Right scores in OLS regression with regression estimates obtained using the combine...

Punctual mutations in the TEM-1 or TEM-2 gene may lead to inhibitor-resistant-TEM (IRT) beta-lactamases with resistance to beta-lactam-beta-lactamase inhibitor combinations and susceptibility to cephalosporins. The aim of this work was to analyze the current epidemiology of IRT beta-lactamases in contemporary clinical Escherichia coli. Isolates were prospectively collected in our hospital (2007...

BACKGROUND Intensive residential treatment (IRT) is effective for severe, treatment-resistant obsessive-compulsive disorder (OCD). We sought to characterize predictors and course of response to IRT. METHODS Admission, monthly, and discharge data were collected on individuals receiving IRT. We examined the association between baseline characteristics and percent change in OCD symptoms as measu...