2-parameter Logistic Item Response Theory Research Articles

Psychometric properties of the MMPI-2-RF Somatic Complaints (RC1) Scale.

The MMPI-2 Restructured Form (MMPI-2-RF; Tellegen & Ben-Porath, 2008) was designed to be psychometrically superior to its MMPI-2 counterpart. However, the test has yet to be extensively evaluated in diverse clinical settings. The purpose of this study was to examine the psychometric properties of the MMPI-2-RF Somatic Complaints (RC1) scale in a clinically relevant population. Participants were 399 patients diagnosed with either epilepsy or psychogenic nonepileptic seizures on the basis of video-electroencephalograph monitoring. The internal structure of the MMPI-2-RF was evaluated using taxometric, confirmatory factor analysis, and item response theory procedures. Data from 4 content-specific scales directly related to RC1 (Malaise, Gastrointestinal Complaints, Head Pain Complaints, and Neurological Complaints) indicated that the latent construct of somatization is a dimensional variable with a bifactor structure. However, consistent with the scale's construction, a unidimensional model also provided adequate fit. A 2-parameter logistic item response theory model better accounted for observed item responses than did 1- or 3-parameter models. Results suggest that the RC1 scale is most precise for T score estimates between 55 and 90. Overall, the scale appears to be well suited for the assessment of somatization.

Assessing the physical violence component of the Revised Conflict Tactics Scales when used in heterosexual couples: an item response theory analysis

Although there are psychometric evaluations of the Revised Conflict Tactics Scales (CTS2) when applied to heterosexual relationships, none has used item response theory (IRT). To address this gap, the present paper assesses the instrument's physical violence subscale. The CTS2 was applied to 764 women who also responded for their partners. Single dimensionality assumption was corroborated. A 2-parameter logistic IRT model was used for estimating location and discriminating power of each item. Differential item functioning and item information pattern along the violence continuum were assessed. Gender differences were detected in 3 out of 12 items. Item coverage of the latent trait spectrum indicated little information at the lower ends, while plenty in the middle and upper ranges. Still, depending on gender, some item overlaps and regions with gaps could be detected. Despite some unresolved problems, the analysis shows that the items form a theoretically coherent information set across the continuum. Provided the user is aware of possible drawbacks, using the physical violence subscale of the CTS2 in heterosexual couples is still a sensible option.

97/04228 Trace element concentrations and stable lead isotopes in soils as tracers of lead pollution in Graft-De Rijp, the Netherlands

Social anxiety disorder is one of the most common mental disorders, and is associated with long term impairment, distress and vulnerability to secondary disorders. Certain types of social fears are more common than others, with public speaking fears typically the most prevalent in epidemiological surveys. The distinction between performance- and interaction-based fears has been the focus of long-standing debate in the literature, with evidence performance-based fears may reflect more mild presentations of social anxiety. This study aims to explicitly test whether different types of social fears differ in underlying social anxiety severity using item response theory techniques. Different types of social fears were assessed using items from three different structured diagnostic interviews in four different epidemiological surveys in the United States (n = 2261, n = 5411) and Australia (n = 1845, n = 1497); and ranked using 2-parameter logistic item response theory models. Overall, patterns of underlying severity indicated by different fears were consistent across the four samples with items functioning across a range of social anxiety. Public performance fears and speaking at meetings/classes indicated the lowest levels of social anxiety, with increasing severity indicated by situations such as being assertive or attending parties. Fears of using public bathrooms or eating, drinking or writing in public reflected the highest levels of social anxiety. Understanding differences in the underlying severity of different types of social fears has important implications for the underlying structure of social anxiety, and may also enhance the delivery of social anxiety treatment at a population level.