Wilco H M Emons

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OBJECTIVE Individuals with increased levels of both negative affectivity (NA) and social inhibition (SI)-referred to as type-D personality-are at increased risk of adverse cardiac events. We used item response theory (IRT) to evaluate NA, SI, and type-D personality as measured by the DS14. The objectives of this study were (a) to evaluate the relative(More)
OBJECTIVE Several authors proposed a shortened version of the State scale of the State-Trait Anxiety Inventory (S-STAI) to obtain a more efficient measurement instrument. Psychometric theory shows that test shortening makes a total score more vulnerable to measurement error, and this may result in inaccurate and biased research results and an increased risk(More)
Short tests containing at most 15 items are used in clinical and health psychology, medicine, and psychiatry for making decisions about patients. Because short tests have large measurement error, the authors ask whether they are reliable enough for classifying patients into a treatment and a nontreatment group. For a given certainty level, proportions of(More)
This study investigates the usefulness of the nonparametric monotone homogeneity model for evaluating and constructing Health-Related Quality-of-Life Scales consisting of polytomous items, and compares it to the often-used parametric graded response model. The nonparametric monotone homogeneity model is a general model of which all known parametric models(More)
The hospital anxiety and depression scale (HADS) measures anxiety and depressive symptoms and is widely used in clinical and nonclinical populations. However, there is some debate about the number of dimensions represented by the HADS. In a sample of 534 Dutch cardiac patients, this study examined (a) the dimensionality of the HADS using Mokken scale(More)
We illustrate the usefulness of person-fit methodology for personality assessment. For this purpose, we use person-fit methods from item response theory. First, we give a nontechnical introduction to existing person-fit statistics. Second, we analyze data from Harter's (1985) Self-Perception Profile for Children (Harter, 1985) in a sample of children(More)
The person-response function (PRF) relates the probability of an individual's correct answer to the difficulty of items measuring the same latent trait. Local deviations of the observed PRF from the expected PRF indicate person misfit. We discuss two new approaches to investigate person fit. The first approach uses kernel smoothing to estimate continuous(More)
BACKGROUND Common mental disorders are strongly associated with long-term sickness absence, which has negative consequences for the individual employee's quality of life and leads to substantial costs for society. It is important to focus on return to work (RTW) during treatment of sick-listed employees with common mental disorders. Factors such as(More)
Purpose Somatoform disorders (physical symptoms without medical explanation that cause dysfunction) are prevalent in the occupational health (OH) care setting and are associated with functional impairment and absenteeism. Availability of psychometric instruments aimed at assessing somatoform disorders is limited. In the OH setting, so far only the(More)
BACKGROUND About six percent of pregnant women suffer from severe fear of childbirth. These women are at increased risk of obstetric labour and delivery interventions and pre- and postpartum complications, e.g., preterm delivery, emergency caesarean section, caesarean section at maternal request, severe postpartum fear of childbirth and trauma anxiety.(More)