A Standardized Generalized Dimensionality Discrepancy Measure and a Standardized Model‐Based Covariance for Dimensionality Assessment for Multidimensional Models

The standardized generalized dimensionality discrepancy measure and the standardized model‐based covariance are introduced as tools to critique dimensionality assumptions in multidimensional item response models. These tools are grounded in a covariance theory perspective and associated connections between dimensionality and local independence. Relative to their precursors, they allow for dimensionality assessment in a more readily interpretable metric of correlations. A simulation study demonstrates the utility of the discrepancy measures’ application at multiple levels of dimensionality analysis, and compares them to factor analytic and item response theoretic approaches. An example illustrates their use in practice.     

Fluctuations of DNA mobility in nanofluidic entropic traps

We studied the mobility of DNA molecules driven by an electric field through a nanofluidic device containing a periodic array of deep and shallow regions termed entropic traps. The mobility of a group of DNA molecules was measured by fluorescent video microscopy. Since the depth of a shallow region is smaller than the DNA equilibrium size, DNA molecules are trapped for a characteristic time and must compress themselves to traverse the boundary between deep and shallow regions. Consistent with previous experimental results, we observed a nonlinear relationship between the mobility and electric field strength, and that longer DNA molecules have larger mobility. In repeated measurements under seemingly identical conditions, we measured fluctuations in the mobility significantly larger than expected from statistical variation. The variation was more pronounced for lower electric field strengths where the trapping time is considerable relative to the drift time. To determine the origin of these fluctuations, we investigated the dependence of the mobility on several variables: DNA concentration, ionic strength of the solvent, fluorescent dye staining ratio, electroosmotic flow, and electric field strength. The mobility fluctuations were moderately enhanced in conditions of reduced ionic strength and electroosmotic flow.     

Assessment of the Learning Environment of Inquiry-Type Laboratories in High School Chemistry

An inquiry-type laboratory has been implemented into the chemistry curriculum in high schools in Israel. In this study, we investigated the idea that generally the science laboratory provides a unique learning environment that differs from the learning environment that exists in classrooms in which other instructional techniques are used. Moreover, the inquiry laboratory provides students with a learning situation in which they are involved in activities that might influence some of the variables that are influencing the learning environment of such laboratories. In this study, the Science Laboratory Environment Inventory (SLEI) was used to assess the students' perceptions of their chemistry laboratory learning environment. Statistical comparison of two groups (control and inquiry) revealed significant differences between the groups regarding their actual perceptions. Moreover, it was found that the differences between the actual and preferred laboratory learning environment were significantly smaller for the inquiry group than for the control group. This revised version was published online in July 2006 with corrections to the Cover Date.     

Using action,reflection and modelling (ARM) in Malaysian primary schools: connecting ‘the ARM theory’ with student teachers’ reported practice

This article presents Malaysian student teachers’ reports of using an action, reflection and modelling (ARM) pedagogical approach during their placements in Malaysian primary schools. The ARM approach was designed to support the implementation of the Malaysian primary school mathematics curriculum, which involved changing classroom practice in learning and teaching. It was developed and used during a Malaysia–UK collaborative project to construct a Bachelor of Education (Honours) degree programme in Primary Mathematics for a cohort of 120 student teachers in Malaysia. The three principles integral to the ARM approach were repeatedly made explicit to the student practitioners who were engaged in learning and teaching on the new degree programme. Using findings from surveys carried out with the students at the end of their first and final placements, this article provides examples of the way some of them described ARM and recounted how they had used the approach in the classroom. Four of these narratives are used as ‘vignettes’ to illustrate the students’ perceptions of using new ways of learning and teaching in primary schools and to inform and enable a discussion of the relationship between theory and practice in teacher education.     

Students' Perceptions of Interpersonal Aspects of the Learning Environment

This study examined variables associated with differences in students' perceptions of interpersonal teacher behavior. The perceptions of 3023 students and 74 teachers in 168 classes in seven secondary schools were used in the analyses. Investigating variance at the student, class, teacher and school levels revealed that several variables are significantly related to students' perceptions: student and teacher gender, student and teacher ethnic background, student age and grade, class size, grade level, subject taught and teacher experience. There were interaction effects between some variables, such as student ethnicity and student gender, as well as student and teacher gender. While significant, the amount of variance explained by these was low (around 10%). The outcomes generally confirmed earlier research, although some new effects were found. Perhaps the main result of the study was its verification of the complex and interactive nature of students' perceptions of the learning environment and researchers' understanding of it.     

Dimensionality in Compensatory MIRT When Complex Structure Exists: Evaluation of DETECT and NOHARM

This study investigated the effect of complex structure on dimensionality assessment in compensatory multidimensional item response models using DETECT- and NOHARM-based methods. The performance was evaluated via the accuracy of identifying the correct number of dimensions and the ability to accurately recover item groupings using a simple matching similarity (SM) coefficient. The DETECT-based methods yielded higher proportion correct than the NOHARM-based methods in two- and three-dimensional conditions, especially when correlations were ≤.60, data exhibited ≤30% complexity, and sample size was 1,000. As the complexity increased and the sample size decreased, the performance of the methods typically diminished. The NOHARM-based methods were either equally successful or better in recovering item groupings than the DETECT-based methods and were mostly affected by complexity levels. The DETECT-based methods were affected largely by the test length, such that with the increase of the number of items, SM coefficients would decrease substantially.     

Career decision-making self-efficacy and institutional integration of underprepared college students

This investigation applied, as the theoretical base, a model of student persistence and departure (Tinto, 1987) to explore the nature of the relationship between career decision-making self-efficacy and integration. Career decision-making self-efficacy identifies students' perceived confidence (self-efficacy) in their ability to plan and execute vocationally relevant tasks in the educational environment. The sample comprised 418 underprepared students. Data were analyzed using correlation, analysis of variance, and multiple regression. There is an interrelationship between perceived career decision-making self-efficacy and integration (overall, social, and academic) for underprepared college students. The variance in students' integration can be explained by their career decision-making self-efficacy and by their initial goals and commitments. Career decision-making self-efficacy surpassed all other variables in explaining the variance in overall and academic integration. Based on these research results, career decision-making self-efficacy should be considered as a variable in future studies of integration, a longitudinal study should be conducted to determine the direct relationship of career decision-making self-efficacy to persistence and attrition, and if a relationship to persistence is found, then the rationale exists for the design and experimental testing of interventions aimed at increasing career decision-making self-efficacy.