Influence of Context on Item Parameters in Forced-Choice Personality Assessments

A fundamental assumption in computerized adaptive testing (CAT) is that item parameters are invariant with respect to context – items surrounding the administered item. This assumption, however, may not hold in forced-choice (FC) assessments, where explicit comparisons are made between items included in the same block. We empirically examined the influence of context on item parameters by comparing parameter estimates from two FC instruments. The first instrument was compiled of blocks of three items, whereas in the second, the context was manipulated by adding one item to each block, resulting in blocks of four. The item parameter estimates were highly similar. However, a small number of significant deviations were observed, confirming the importance of context when designing adaptive FC assessments. Two patterns of such deviations were identified, and methods to reduce their occurrences in a FC CAT setting were proposed. It was shown that with a small proportion of violations of the parameter invariance assumption, score estimation remained stable

Measuring pregnancy planning: An assessment of the London Measure of Unplanned Pregnancy among urban, south Indian women

Copyright © 2010 Corinne H. Rocca et al. This open-access work is published under the terms of the Creative Commons Attribution NonCommercial License 2.0 Germany, which permits use, reproduction & distribution in any medium for non-commercial purposes, provided the original author(s) and source are given credit. See http:// creativecommons.org/licenses/by-nc/2.0/de/.We evaluated the psychometric properties of the London Measure of Unplanned Pregnancy among Indian women using classical methods and Item Response Modeling. The scale exhibited good internal consistency and internal structure, with overall scores correlating well with each item’s response categories. Items performed similarly for pregnant and non-pregnant women, and scores decreased with increasing parity, providing evidence for validity. Analyses detected small disadvantages, including low endorsement of middle response categories and some evidence of differential item functioning by parity. We conclude that the LMUP is suitable for use in India and recommend steps for improving scale performance for this cultural context.National Institute of Child Health and Human Development and the Levis Strauss Foundation

Hyperarousal symptoms after traumatic and nontraumatic births

Background: Measurement is critical in postnatal posttraumatic stress disorder (PTSD) because symptoms may be influenced by normal postnatal phenomena such as physiological changes and fatigue. Objective: This study examined: (1) whether hyperarousal symptoms differ between women who have traumatic or nontraumatic births; (2) whether the construct of hyperarousal is coherent in postnatal women; and (3) whether hyperarousal symptoms are useful for identifying women who have traumatic births or PTSD. Methods: A survey of PTSD symptoms in 1,078 women recruited via the community or Internet who completed an online or paper questionnaire measuring childbirth-related PTSD symptoms between 1 and 36 months after birth. Women who had a traumatic birth as defined by DSM-IV criterion A (n = 458) were compared with women who did not have a traumatic birth (n = 591). Results: A one-factor dimension of hyperarousal was identified that included all five hyperarousal items. Diagnostic criteria of two or more hyperarousal symptoms in the previous week were reported by 75.3% of women with traumatic birth and 50.5% of women with nontraumatic births. The difference in mean hyperarousal symptoms between groups was substantial at 0.76 of a standard deviation (Hedge’s g, CI = 0.64, 0.89). A larger difference was observed between women with and without diagnostic PTSD (g = 1.64, CI 1.46, 1.81). However, receiver operating characteristic analyses showed hyperarousal symptoms have poor specificity and alternative ways of calculating symptoms did not improve this. Comparison with other PTSD symptoms found re-experiencing symptoms were most accurate at identifying women with traumatic births. Conclusions: Results suggest hyperarousal symptoms are associated with traumatic birth and are a coherent construct in postnatal women. However, they have poor specificity and should only be used as part of diagnostic criteria, not as a sole indicator

Structural, item, and test generalizability of the psychopathology checklist - revised to offenders with intellectual disabilities

The Psychopathy Checklist–Revised (PCL-R) is the most widely used measure of psychopathy in forensic clinical practice, but the generalizability of the measure to offenders with intellectual disabilities (ID) has not been clearly established. This study examined the structural equivalence and scalar equivalence of the PCL-R in a sample of 185 male offenders with ID in forensic mental health settings, as compared with a sample of 1,212 male prisoners without ID. Three models of the PCL-R’s factor structure were evaluated with confirmatory factor analysis. The 3-factor hierarchical model of psychopathy was found to be a good fit to the ID PCL-R data, whereas neither the 4-factor model nor the traditional 2-factor model fitted. There were no cross-group differences in the factor structure, providing evidence of structural equivalence. However, item response theory analyses indicated metric differences in the ratings of psychopathy symptoms between the ID group and the comparison prisoner group. This finding has potential implications for the interpretation of PCL-R scores obtained with people with ID in forensic psychiatric settings

Equivalence of Narcissistic Personality Inventory constructs and correlates across scoring approaches and response formats

The prevalent scoring practice for the Narcissistic Personality Inventory (NPI) ignores the forced-choice nature of the items. The aim of this study was to investigate whether findings based on NPI scores reported in previous research can be confirmed when the forced-choice nature of the NPI’s original response format is appropriately modeled, and when NPI items are presented in different response formats (true/false or rating scale). The relationships between NPI facets and various criteria were robust across scoring approaches (mean score vs. model-based), but were only partly robust across response formats. In addition, the scoring approaches and response formats achieved equivalent measurements of the vanity facet and in part of the leadership facet, but differed with respect to the entitlement facet

Accelerated in vivo proliferation of memory phenotype CD4+ T-cells in human HIV-1 infection irrespective of viral chemokine co-receptor tropism.

CD4(+) T-cell loss is the hallmark of HIV-1 infection. CD4 counts fall more rapidly in advanced disease when CCR5-tropic viral strains tend to be replaced by X4-tropic viruses. We hypothesized: (i) that the early dominance of CCR5-tropic viruses results from faster turnover rates of CCR5(+) cells, and (ii) that X4-tropic strains exert greater pathogenicity by preferentially increasing turnover rates within the CXCR4(+) compartment. To test these hypotheses we measured in vivo turnover rates of CD4(+) T-cell subpopulations sorted by chemokine receptor expression, using in vivo deuterium-glucose labeling. Deuterium enrichment was modeled to derive in vivo proliferation (p) and disappearance (d*) rates which were related to viral tropism data. 13 healthy controls and 13 treatment-naive HIV-1-infected subjects (CD4 143-569 cells/ul) participated. CCR5-expression defined a CD4(+) subpopulation of predominantly CD45R0(+) memory cells with accelerated in vivo proliferation (p = 2.50 vs 1.60%/d, CCR5(+) vs CCR5(-); healthy controls; P<0.01). Conversely, CXCR4 expression defined CD4(+) T-cells (predominantly CD45RA(+) naive cells) with low turnover rates. The dominant effect of HIV infection was accelerated turnover of CCR5(+)CD45R0(+)CD4(+) memory T-cells (p = 5.16 vs 2.50%/d, HIV vs controls; P<0.05), naïve cells being relatively unaffected. Similar patterns were observed whether the dominant circulating HIV-1 strain was R5-tropic (n = 9) or X4-tropic (n = 4). Although numbers were small, X4-tropic viruses did not appear to specifically drive turnover of CXCR4-expressing cells (p = 0.54 vs 0.72 vs 0.44%/d in control, R5-tropic, and X4-tropic groups respectively). Our data are most consistent with models in which CD4(+) T-cell loss is primarily driven by non-specific immune activation

A vision of elementary school leadership : a reflective research paper

I want to help children feel that sense of belonging, self-worth, and pride that comes from learning. My task as an administrator will be to put the necessary pieces in place to make sure that happens. One strand woven throughout all my experiences is the importance of building and sustaining relationships. Two key beliefs I will discuss in the following pages include: 1. The keys to helping our students find success is in the effectiveness of our teachers. 2. An administrator is responsible for creating a nurturing school environment, which enables him/her to lead students, families and staff toward a shared sense of purpose

Estimating selection pressures on HIV-1 using phylogenetic likelihood models

Human immunodeficiency virus (HIV-1) can rapidly evolve due to selection pressures exerted by HIV-specific immune responses, antiviral agents, and to allow the virus to establish infection in different compartments in the body. Statistical models applied to HIV-1 sequence data can help to elucidate the nature of these selection pressures through comparisons of non-synonymous (or amino acid changing) and synonymous (or amino acid preserving) substitution rates. These models also need to take into account the non-independence of sequences due to their shared evolutionary history. We review how we have developed these methods and have applied them to characterize the evolution of HIV-1 in vivo.To illustrate our methods, we present an analysis of compartment-specific evolution of HIV-1 env in blood and cerebrospinal fluid and of site-to-site variation in the gag gene of subtype C HIV-1