Recently, several authors have introduced and discussed the advantage of the use of item response theory models (IRT) to construct personality scales and to explore the structure of personality data sets. For example, Waller, Tellegen, McDonald, and Lykken (1996) contrasted the use of IRT to principal factor analysis and Reise and Waller (in press) discussed the choice of an IRT model to analyz...

BACKGROUND Following the severe acute respiratory syndrome (SARS) outbreak, remote-sensing infrared thermography (IRT) has been advocated as a possible means of screening for fever in travelers at airports and border crossings, but its applicability has not been established. We therefore set out to evaluate (1) the feasibility of IRT imaging to identify subjects with fever, and (2) the optimal ...

Linear factor analysis (FA) models can be reliably tested using test statistics based on residual covariances. We show that the same statistics can be used to reliably test the fit of item response theory (IRT) models for ordinal data (under some conditions). Hence, the fit of an FA model and of an IRT model to the same data set can now be compared. When applied to a binary data set, our experi...

In this review, we examine studies that use item response theory (IRT) to explore the psychometric properties of clinical measures. Next, we consider how IRT has been used in clinical research for: scale linking, computerized adaptive testing, and differential item functioning analysis. Finally, we consider the scale properties of IRT trait scores. We conclude that there are notable differences...

For specific applications of infrared thermography (IRT) in the field of human medicine diagnosis, well defined standard operating procedures are used (e.g. controlled ambient conditions). In contrast, when IRT is used in the veterinary and animal science field, examinations are not always performed under controlled ambient conditions. This leads to unavoidable influences to the surface tempera...

We have measured serum immunoreactive trypsin (IRT) and serum pancreatic isoamylase (PIA) activities using commercially available kits in 37 cystic fibrosis (CF) patients and 46 hospital controls of similar age range. Immunoreactive trypsin was more often abnormal than PIA (26/37 v 18/37 abnormal respectively); IRT will be particularly useful as an additional diagnostic test in older children, ...

BACKGROUND Patients-Reported Outcomes (PRO) are increasingly used in clinical and epidemiological research. Two main types of analytical strategies can be found for these data: classical test theory (CTT) based on the observed scores and models coming from Item Response Theory (IRT). However, whether IRT or CTT would be the most appropriate method to analyse PRO data remains unknown. The statis...

We investigated the effect of 8 weeks of high intensity interval training (HIT) and isoinertial resistance training (IRT) on cardiovascular fitness, muscle mass-strength and risk factors of metabolic syndrome in 12 healthy older adults (68 yy ± 4). HIT consisted in 7 two-minute repetitions at 80%-90% of V˙O2max, 3 times/w. After 4 months of recovery, subjects were treated with IRT, which inclu...

Item response theory (IRT) has a number of potential advantages over classical test theory in assessing self-reported health outcomes. IRT models yield invariant item and latent trait estimates (within a linear transformation), standard errors conditional on trait level, and trait estimates anchored to item content. IRT also facilitates evaluation of differential item functioning, inclusion of ...

Figure 1. Salivary gland scintigraphy performed before (March 2005) and after (August 2005) iodine-131 internal radiation therapy (I-131 IRT). Anterior images obtained at 10 and 20 minutes after intravenous injection of Tc-99m, and at 5 minutes after washout by Vitamin C are shown. Original scintigraphy was performed as a dynamic study with 1 min/frame. Significantly higher accumulation was obs...