BACKGROUND Differential Item Functioning (DIF) is investigated to ensure that each item displays a consistent pattern of responses irrespective of the characteristics of the respondents. Assessing DIF helps to understand the nature of instruments, to assess the quality of a measure and to interpret results. This study aimed to examine whether the items of the Quality of Life Enjoyment and Satis...

AIM The aim of this study was to assess accuracy of echocardiography in the measurement of left ventricular ejection fraction (LVEF), enddiastolic volume (EDV) and endsystolic volume (ESV) compared with gated SPECT. METHODS A total of 70 patients with left ventricular systolic dysfunction were enrolled to study. Median of the time interval between gated SPECT and echocardiography was 1 hour. ...

The differentiation-inducing factor, DIF, was previously shown to induce stalk cell differentiation in Dictyostelium discoideum cells incubated as submerged monolayers. We investigated the mechanism that regulates the differentiation of stalk cells in the intact organism. It was found that in migrating or submerged slugs DIF cannot induce stalk cell differentiation, which is most likely due to ...

The detection of differential item functioning (DIF) is an essential step in increasing the validity of a test for all groups. The item response theory (IRT) model comparison approach has been shown to be the most flexible and powerful method for DIF detection; however, it is computationally-intensive, requiring many model-refittings. The Wald test, originally employed by Lord for DIF detection...

The generalizability aspect of Construct validity, as proposed by Messick (1989), requires that a test measures the same trait across different samples from the same population. Differential Item functioning (DIF) analysis is a key component in the fairness evaluation of educational tests. University entrance exam for the candidates who seek admission into master's English programs (MEUEE) at I...

Cell death in the model organism Dictyostelium, as studied in monolayers in vitro, can be induced by the polyketide DIF-1 or by the cyclical dinucleotide c-di-GMP. c-di-GMP, a universal bacterial second messenger, can trigger innate immunity in bacterially infected animal cells and is involved in developmental cell death in Dictyostelium. We show here that c-di-GMP was not sufficient to induce ...

Competition for foreign direct investment (FDI) among developing countries has intensified in recent years. Using a sample of 68 developing countries across dif ferent regions, with data from 1975-2005, this paper investigates whether Latin America and the Caribbean (LAC) dif fers from non-LAC regions in regard to determinants of FDI; the evidence suggests that there are dif ferences. In partic...

DH: dermatitis herpetiformis DIF: direct immunofluorescence INTRODUCTION Dermatitis herpetiformis (DH) is an autoimmune, subepidermal blistering disease associated with gluten sensitivity. It commonly manifests as intensely pruritic papules and vesicles on the extensor surfaces of extremities in a symmetric distribution. Classic histologic findings and data from direct immunofluorescent (DIF) s...

Differential item functioning (DIF), as an assessment tool, has been widely used in quantitative psychology, educational measurement, business management, and insurance and healthcare industries. The purpose of DIF analyses is to detect response differences of items in questionnaires, rating scales, or tests across different subgroups (e.g., gender), while controlling for ability level. There a...