Evaluation of Dimensionality in the Assessment of Internal Consistency Reliability: Coefficient Alpha and Omega Coefficients

In the lead article, Davenport, Davison, Liou, & Love demonstrate the relationship among homogeneity, internal consistency, and coefficient alpha, and also distinguish among them. These distinctions are important because too often coefficient alpha—a reliability coefficient—is interpreted as an index of homogeneity or internal consistency. We argue that factor analysis should be conducted before calculating internal consistency estimates of reliability. If factor analysis indicates the assumptions underlying coefficient alpha are met, then it can be reported as a reliability coefficient. However, to the extent that items are multidimensional, alternative internal consistency reliability coefficients should be computed based on the parameter estimates of the factor model. Assuming a bifactor model evidenced good fit, and the measure was designed to assess a single construct, omega hierarchical—the proportion of variance of the total scores due to the general factor—should be presented. Omega—the proportion of variance of the total scores due to all factors—also should be reported in that it represents a more traditional view of reliability, although it is computed within a factor analytic framework. By presenting both these coefficients and potentially other omega coefficients, the reliability results are less likely to be misinterpreted.     

Reliability,Dimensionality, and Internal Consistency as Defined by Cronbach: Distinct Albeit Related Concepts

This article uses definitions provided by Cronbach in his seminal paper for coefficient α to show the concepts of reliability, dimensionality, and internal consistency are distinct but interrelated. The article begins with a critique of the definition of reliability and then explores mathematical properties of Cronbach's α. Internal consistency and dimensionality are then discussed as defined by Cronbach. Next, functional relationships are given that relate reliability, internal consistency, and dimensionality. The article ends with a demonstration of the utility of these concepts as defined. It is recommended that reliability, internal consistency, and dimensionality each be quantified with separate indices, but that their interrelatedness be recognized. High levels of unidimensionality and internal consistency are not necessary for reliability as measured by α nor, more importantly, for interpretability of test scores.     

Digital ITEMS Module 2: Scale Reliability in Structural Equation Modeling

In this ITEMS module, we frame the topic of scale reliability within a confirmatory factor analysis and structural equation modeling (SEM) context and address some of the limitations of Cronbach's α. This modeling approach has two major advantages: (1) it allows researchers to make explicit the relation between their items and the latent variables representing the constructs those items intend to measure, and (2) it facilitates a more principled and formal practice of scale reliability evaluation. Specifically, we begin the module by discussing key conceptual and statistical foundations of the classical test theory model and then framing it within an SEM context; we do so first with a single item and then expand this approach to a multi‐item scale. This allows us to set the stage for presenting different measurement structures that might underlie a scale and, more importantly, for assessing and comparing those structures formally within the SEM context. We then make explicit the connection between measurement model parameters and different measures of reliability, emphasizing the challenges and benefits of key measures while ultimately endorsing the flexible McDonald's ω over Cronbach's α. We then demonstrate how to estimate key measures in both a commercial software program (Mplus) and three packages within an open‐source environment (R). In closing, we make recommendations for practitioners about best practices in reliability estimation based on the ideas presented in the module.     

Silencing of DsbA-L gene impairs the PPARγ agonist function of improving insulin resistance in a high-glucose cell model

Disulfide-bond A oxidoreductase-like protein (DsbA-L) is a molecular chaperone involved in the multimerization of adiponectin. Recent studies have found that DsbA-L is related to metabolic diseases including gestational diabetes mellitus (GDM), and can be regulated by peroxisome proliferator-activated receptor γ (PPARγ) agonists; the specific mechanism, however, is uncertain. Furthermore, the relationship between DsbA-L and the novel adipokine chemerin is also unclear. This article aims to investigate the role of DsbA-L in the improvement of insulin resistance by PPARγ agonists in trophoblast cells cultured by the high-glucose simulation of GDM placenta. Immunohistochemistry and western blot were used to detect differences between GDM patients and normal pregnant women in DsbA-L expression in the adipose tissue. The western blot technique was performed to verify the relationship between PPARγ agonists and DsbA-L, and to explore changes in key molecules of the insulin signaling pathway, as well as the effect of chemerin on DsbA-L. Results showed that DsbA-L was significantly downregulated in the adipose tissue of GDM patients. Both PPARγ agonists and chemerin could upregulate the level of DsbA-L. Silencing DsbA-L affected the function of rosiglitazone to promote the phosphatidylinositol 3-kinase (PI3K)-protein kinase B (PKB)/AKT pathway. Therefore, it is plausible to speculate that DsbA-L is essential in the environment of PPARγ agonists for raising insulin sensitivity. Overall, we further clarified the mechanism by which PPARγ agonists improve insulin resistance.     

Components of Variance of Scales With a Bifactor Subscale Structure From Two Calculations of α

Since Cronbach's (1951) elaboration of α from its introduction by Guttman (1945), this coefficient has become ubiquitous in characterizing assessment instruments in education, psychology, and other social sciences. Also ubiquitous are caveats on the calculation and interpretation of this coefficient. This article summarizes a recent contribution (Andrich, 2015) on the use of coefficient α which complements these many caveats. It shows that in the presence of a simple bifactor structure of a scale where unique components of variance are homogeneous in magnitude, three components of variance and the common latent common correlation among the subscales can be calculated from the ratio of two calculations of α, one at the level of the items, the other at the level of the subscales. It was suggested that these two ready calculations and their interpretation, and the reporting of all four indices in the analysis of scales with a subscale structure, would reduce the misinterpretation of this coefficient. An illustrative example of the application of the calculations is also shown.     

Positive temperature coefficient of resistivity effects of semiconducting （Bi（1/2）Na（1/2））TiO3-CaTiO3-BaTiO3 ceramics sintered in air atmosphere

Y^3＋-doped （Bi 1/2 Na 1/2） TiO 3-CaTiO 3-BaTiO 3 （BNCBT） positive temperature coefficient of resistivity （PTCR） ceramics sintered in air atmosphere were investigated in this study. （Bi 1/2 Na 1/2） TiO 3 （BNT） component can remarkably increase the onset temperature T c of PTCR ceramics with the expense of the resistivity R 25 increase. CaTiO 3 （9–27 mol%） component can decrease the resistivity, and adjust the effects of BNT phase on the T c point. For the sample containing 3 mol% CaTiO 3 , T c raises from 122 ℃ to 153 ℃ when only 0.6 mol% BNT added, while for the ones with higher CaTiO 3 content （9–27 mol%）, T c is only increased by a rate of 8–9℃/1.0 mol% BNT. The effects of BNT and CaTiO 3 components on R25/Rmin （negative temperature coefficient effect） are also discussed.     

Digital ITEMS Module 1: Reliability in Classical Test Theory

In this ITEMS module, we provide a two‐part introduction to the topic of reliability from the perspective of classical test theory (CTT). In the first part, which is directed primarily at beginning learners, we review and build on the content presented in the original didactic ITEMS article by Traub and Rowley (1991). Specifically, we discuss the notion of reliability as an intuitive everyday concept to lay the foundation for its formalization as a reliability coefficient via the basic CTT model. We then walk through the step‐by‐step computation of key reliability indices and discuss the data collection conditions under which each is most suitable. In the second part, which is directed primarily at intermediary learners, we present a distribution‐centered perspective on the same content. We discuss the associated assumptions of various CTT models ranging from parallel to congeneric, and review how these affect the choice of reliability statistics. Throughout the module, we use a customized Excel workbook with sample data and basic data manipulation functionalities to illustrate the computation of individual statistics and to allow for structured independent exploration. In addition, we provide quiz questions with diagnostic feedback as well as short videos that walk through sample exercises within the workbook.     

Educating children on the autism spectrum: preconditions for inclusion and notions of ‘best autism practice’ in the early years

This article draws together findings from expert evidence and empirical studies to identify the preconditions for developing inclusive learning environments for young children on the autism spectrum. It concludes that in order to develop ‘best practice’, practitioners need to adapt interventions to the unique needs of the individual child, work in partnership with parents and other professionals, create enabling environments and be informed by a developmental approach to learning. Practitioners need to have knowledge of the autism spectrum and how it impacts on the child. Careful assessment of the individual child is also crucial. Finally, it is important to ensure that these young children receive direct teaching in communication and language, social understanding and skills, as well as learning with and through peers.     

The NSEAD Survey Report 2015–16: Political Reflections from Two Art and Design Educators

In 2015 the (UK) National Society for Education in Art and Design (NSEAD) conducted their biggest and most comprehensive survey to date with art and design educators. Some 1,191 teachers and lecturers employed in early years to further education settings across England and Wales responded to the survey, which aimed to capture how government policy since 2010 has affected art and design education. Four key areas were examined: curriculum provision; value given to the subject within the school community; professional development opportunities; and well‐being and workload. The results are troubling, indicating a systemic marginalisation of art and design across all sectors, evident in a reduction in choice, provision and curriculum time, and evidence of falling standards in student attainment at primary to secondary transfer. We supported the NSEAD with constructing the survey and writing the report and in this article we utilise the Survey Report to fuel a broader discussion about our concerns regarding the demise of art and design education. Value is identified as an essential theme and we posit that our subject, largely due to neoliberalist policy, is currently perceived as a ‘bimbo’: attractive, but unintelligent and frivolous. In this article we pay particular attention to the value of art and design education from a political perspective, challenging narrow government agendas.     

FLT3 and NPM1 mutations in Chinese patients with acute myeloid leukemia and normal cytogenetics

Mutations of fms-like tyrosine kinase 3 (FLT3) and nucleophosmin (NPM1) exon 12 genes are the most common abnormalities in adult acute myeloid leukemia (AML) with normal cytogenetics. To assess the prognostic impact of the two gene mutations in Chinese AML patients, we used multiplex polymerase chain reaction (PCR) and capillary electrophoresis to screen 76 AML patients with normal cytogenetics for mutations in FLT3 internal tandem duplication (FLT3/ITD) and exon 12 of the NPM1 gene. FLT3/ITD mutation was detected in 15 (19.7%) of 76 subjects, and NPM1 mutation in 20 (26.3%) subjects. Seven (9.2%) cases were positive for both FLT3/ITD and NPM1 mutations. Significantly more FLT3/ITD aberration was detected in subjects with French-American-British (FAB) M1 (42.8%). NPM1 mutation was frequently detected in subjects with M5 (47.1%) and infrequently in subjects with M2 (11.1%). FLT3 and NPM1 mutations were significantly associated with a higher white blood cell count in peripheral blood and a lower CD34 antigen expression, but not age, sex, or platelet count. Statistical analysis revealed that the FLT3/ITDpositive group had a lower complete remission (CR) rate (53.3% vs. 83.6%). Survival analysis showed that the FLT3/ITD-positive/NPM1 mutation-negative group had worse overall survival (OS) and relapse-free survival (RFS). The FLT3/ITD-positive/NPM1 mutation-positive group showed a trend towards favorable survival compared with the FLT3/ITD-positive/NPM1 mutation-negative group (P=0.069). Our results indicate that the FLT3/ITD mutation might be a prognostic factor for an unfavorable outcome in Chinese AML subjects with normal cytogenetics, while NPM1 mutation may be a favorable prognostic factor for OS and RFS in the presence of FLT3/ITD.