Librarians Use of Web 2.0 in UK Medical Schools: Outcomes of A National Survey

Using the results of an Email survey, this paper reviews the use of Web 2.0 technologies by librarians working in UK Medical Schools. Web 2.0 has been hailed as an innovation for facilitation of two way communication on the net, and it is, therefore, timely to measure how effectively librarians are capturing this opportunity for increased student engagement. The social nature of Web 2.0 can be particularly appropriate for undergraduate medical students who fit their studies around the unsocial hours and geographical isolation of clinical placements. This paper will investigate library use of blogs, Facebook, and Twitter. Consideration will also be given as to whether they facilitate a more collabroative library service or if they leave undergraduate medical students swamped with yet more information to manage.     

Structural Equation Models of Latent Interactions: Clarification of Orthogonalizing and Double-Mean-Centering Strategies

The purpose of this investigation is to compare a new (double-mean-centering) strategy to estimating latent interactions in structural equation models with the (single) mean-centering strategy (Marsh, Wen, & Hau, 2004 Marsh, H. W., Wen, Z. and Hau, K. T. 2004. Structural equation models of latent interactions: Evaluation of alternative estimation strategies and indicator construction.. Psychological Methods, 9: 275–300. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar], 2006 Marsh, H. W., Wen, Z. and Hau, K. T. 2006. “Structural equation models of latent interaction and quadratic effects”. In A second course in structural equation modeling Edited by: Hancock, G. and Mueller, R. 225–265. Greenwich, CT: Information Age.  [Google Scholar]) and the orthogonalizing strategy (Little, Bovaird, & Widaman, 2006 Little, T. D., Bovaird, J. A. and Widaman, K. F. 2006. On the merits of orthogonalizing powered and product term: Implications for modeling interactions among latent variables.. Structural Equation Modeling, 13: 497–519. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]; Marsh et al., 2007 Marsh, H. W., Wen, Z., Hau, K. T., Little, T. D., Bovaird, J. A. and Widaman, K. F. 2007. Unconstrained structural equation models of latent interactions: Contrasting residual- and mean-centered approaches.. Structural Equation Modeling, 14: 570–580. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]). A key benefit of the orthogonalizing strategy is that it eliminated the need to estimate a mean structure as required by the mean-centering strategy, but required a potentially cumbersome 2-step estimation procedure. In contrast, the double-mean-centering strategy eliminates both the need for the mean structure and the cumbersome 2-stage estimation procedure. Furthermore, although the orthogonalizing and double-mean-centering strategies are equivalent when all indicators are normally distributed, the double-mean-centering strategy is superior when this normality assumption is violated. In summary, we recommend that applied researchers wanting to estimate latent interaction effects use the double-mean-centering strategy instead of either the single-mean-centering or orthogonalizing strategies, thus allowing them to ignore the cumbersome mean structure.     

Pairwise deletion for missing data in structural equation models: Nonpositive definite matrices,parameter estimates,goodness of fit,and adjusted sample sizes

The use of sample covariance matrices constructed with pairwise deletion for data missing completely at random (S_PW) is addressed in a simulation study based on 3 sample sizes (n = 200, 500, 1,000) and 5 levels of missing data (%miss = 0, 1, 10, 25, and 50). Parameter estimates were unbiased, parameter variability was largely explicable in terms of the number of nonmissing cases, and no sample covariance matrices were nonpositive definite except when %miss was 50 and the sample size was 200. However, nominal χ² test statistics (and, thus, fit indices based on χ²s) were substantially biased by %miss and its interaction with N. Corrected χ²s based on the minimum, mean, and maximum number of nonmissing cases per measured variables and cases per covariance term (NPC) reduced but did not eliminate the bias. Empirically derived power functions did substantially better but may not generalize to other situations. Whereas the minimum NPC (the default in the SPSS version of LISREL) is probably better than most simple alternatives in many applications, the problem of how to assess fit for models fit to S_PWS has no simple solution; caution is recommended, and there is need for further research with more suitable methods for this problem.     

Longitudinal stability of latent means and individual differences: A unified approach

We examined the stability of responses to a multi‐item self‐esteem scale collected on five occasions over an 8‐year period. A wide variety of approaches were critically examined that considered the stability of means, individual differences (i.e., test‐retest correlations), and factor structures using traditional approaches (e.g., ANOVA and correlations) and structural equation models. Structural equation models based on multiple indicators provided a unified analytic approach for evaluating different aspects of stability and offered important advantages over traditional approaches. We describe a hierarchy of invariances and the nature of interpretations that are justified by different patterns of factor structure invariance associated with each level. We conclude that the assumptions underlying the typical repeated‐measures ANOVA approach to testing mean differences in longitudinal data are far more restrictive, less easily tested, and less likely to be met than those in the structural equation modeling approach advocated here, and that the use of ANOVA for this purpose requires a huge leap of faith that can rarely be justified on logical or empirical grounds.     

Evaluating Model Fit With Ordered Categorical Data Within a Measurement Invariance Framework: A Comparison of Estimators

A paucity of research has compared estimation methods within a measurement invariance (MI) framework and determined if research conclusions using normal-theory maximum likelihood (ML) generalizes to the robust ML (MLR) and weighted least squares means and variance adjusted (WLSMV) estimators. Using ordered categorical data, this simulation study aimed to address these queries by investigating 342 conditions. When testing for metric and scalar invariance, Δχ² results revealed that Type I error rates varied across estimators (ML, MLR, and WLSMV) with symmetric and asymmetric data. The Δχ² power varied substantially based on the estimator selected, type of noninvariant indicator, number of noninvariant indicators, and sample size. Although some the changes in approximate fit indexes (ΔAFI) are relatively sample size independent, researchers who use the ΔAFI with WLSMV should use caution, as these statistics do not perform well with misspecified models. As a supplemental analysis, our results evaluate and suggest cutoff values based on previous research.     

Assistance and Accountability in Externally Managed Schools: The Case of Edison Schools,Inc.

Edison Schools, Inc., is the largest and most visible among a growing number of Education Management Organizations that have entered into contracts to manage public schools, including both conventional and charter schools. Edison's approach to managing schools is comprehensive, and it distinguishes itself from most other school improvement strategies by simultaneously addressing both the resources and assistance provided to schools and the accountability systems under which school staff operate. In this article we explore the ways in which the assistance and resources provided by Edison (including diverse professional development opportunities, materials, technology, and other tools), as well as accountability mechanisms (such as monitoring and rewards), have translated into principal and teacher actions, and the factors that facilitated or constrained educators' efforts to implement the Edison design and improve teaching and learning. Drawing on data gathered from extensive interviews, observations, and document reviews collected during a four-year comprehensive study of Edison schools, we demonstrate how Edison intends to promote not only educators' capacity but also their motivation and opportunity to deliver high-quality instruction. We examine variation that occurs across schools as teachers and principals respond to these system-level efforts. In addition, we identify several important predictors of variation in implementation, including the strength of instructional leadership provided by the principal and the presence or absence of district-imposed constraints such as union contract rules.     

Developing and managing school human capital for information and communication technology integration: a case study of a school-based e-learning project in Hong Kong

The application of information and communication technology (ICT) in education has been gaining attention worldwide. Educators and school administrators are interested in the myriad possibilities offered by new technologies to enrich teaching materials and to provide ubiquitous learning environments to enhance students’ learning. This case study examined the implementation of a school-based e-learning initiative in a primary school in Hong Kong by focusing on the development and management of forms of school human capital. The findings drew from interviews with 25 staff members in the case school and elucidated how school reform and transformation were effected through the development and management of intellectual, social, and organisational capitals. The interplay between these three forms of school human capitals highlighted the significance of shared vision, differentiated leadership as well as a culture of learning community in advancing towards ICT integration. Suggestions are made for establishing practices of distributed leadership and professional learning communities in the case school and other settings undertaking ICT integration.