Estimating Variance Components from Sparse Data Matrices in Large-Scale Educational Assessments

In generalizability theory studies in large-scale testing contexts, sometimes a facet is very sparsely crossed with the object of measurement. For example, when assessments are scored by human raters, it may not be practical to have every rater score all students. Sometimes the scoring is systematically designed such that the raters are consistently grouped throughout the scoring, so that the data can be analyzed as raters nested within teams. Other times, rater pairs are randomly assigned for each student, such that each rater is paired with many other raters at different times. One possibility for this scenario is to treat the data as if raters were nested within students. Because the raters are not truly independent across all students, the resulting variance components could be somewhat biased. This study illustrates how the bias will tend to be small in large-scale studies.     

Teaching About Electricity in Primary School Multimodality and Variation Theory as Analytical Lenses

Research in Science Education - Primary school topics involving abstract concepts are challenging to teach. Electric circuits can be simply constructed but complex to explain. New approaches in...     

Effects of swing-weight on swing speed and racket power

Abstract

Measurements are presented of the speed at which six different rods could be swung by four male students. Three of the rods had the same mass but their swing-weight (i.e. moment of inertia) differed by large factors. The other three rods had the same swing-weight but different masses. Our primary objective was to quantify the effects of mass and swing-weight on swing speed. The result has a direct bearing on whether baseball, tennis, cricket and golf participants should choose a heavy or light implement to impart maximum speed to a ball. When swinging with maximum effort, swing speed (V) was found to decrease as swing-weight (I _o) increased, according to the relation V?=?C/I _o ⁿ , where C is a different constant for each participant and n?=?0.27 when I _o >?0.03 kg?·?m². Remarkably similar results were obtained previously with softball bats (where n?=?0.25) and golf clubs (where n?=?0.26). Swing speed remained approximately constant as swing mass increased (when keeping swing-weight fixed). The implications for racket power are discussed.     

Book Reviews

Serial Publications: Guidelines for Good Practice in Publishing Printed and Electronic Journals, 2nd edition, by Diane Brown, Elaine Stott and Anthony Watkinson Association of Learned and Professional Society Publishers 2003, £27 (members), £30 (non‐members), 108 pp., paperback. ISBN 0‐907341‐22‐5. Available from http://www.alpsp.org/pub3.htm The Case for Institutional Repositories: A SPARC Position Paper prepared by Raym Crow, SPARC Senior Consultant Scholarly Publishing and Academic Resources Coalition, Washington DC. Release 1.0, 2002. Available at: www.arl.org/sparc The Case for Institutional Repositories: A SPARC Position Paper prepared by Raym Crow, SPARC Senior Consultant Scholarly Publishing and Academic Resources Coalition, Washington, DC. Release 1.0, 2002. Available at: www.arl.org/sparc Internet Law: Text and Materials by Chris Reed Butterworths Tolley, 2000, £24.95, paperback. ISBN 0406981418 Intellectual Property Law by Lionel Bently and Brad Sherman Oxford University Press, Oxford, 2001, £32.99 (paperback), 1136 pp. ISBN 0‐19‐876343‐3 Clearing the Way: Copyright Clearance in UK Libraries by Elizabeth Gadd LISU Occasional Paper no. 31, Library & Information Statistics Unit (LISU), Department of Information Science, Loughborough University. ISBN 1 901786 51 X Electronic Journals and User Behaviour: Learning for the Future from the SuperJournal Project by David Pullinger and Christine Baldwin Deedot Press, 2002, £14.95. ISBN 0‐954‐2924‐0‐5 Electronic Ecology: A Case Study of Electronic Journals in Context by Karla L. Hahn Association of Research Libraries, 79 pp., 2001, $45. ISBN 0‐918006‐46‐1 The Transition from Paper: Where Are We Going and How Will We Get There edited by R. Stephen Berry and Anne Simon Moffat American Academy of Arts and Sciences, published online (2001): www.amacad.org/publications/trans.htm The Transition from Paper: Where Are We Going and How Will We Get There edited by R. Stephen Berry and Anne Simon Moffat American Academy of Arts and Sciences, published online (2001): www.amacad.org/publications/trans.htm E‐Serials, Publishers, Libraries, Users and Standards, 2nd edn, edited by Wayne Jones The Haworth Press Inc., 2003, 294 pp. paperback ISBN 0789012294     

Who determines teacher work: The teacher,the organization,or both?

This paper examines how teachers responded when some organizational constraints on their work were loosened and why they responded as they did. It first reviews the sociological literature on teacher work to identify the main determinants studied. It then presents results of an ethnographic study of teachers in an urban school. The literature tends to portray teacher work as overly determined and may remove more responsibility from teachers for determining their own work than is warranted.     

Infants Prefer Infant‐Directed Song Over Speech

In their everyday communication, parents do not only speak but also sing with their infants. However, it remains unclear whether infants' can discriminate speech from song or prefer one over the other. The present study examined the ability of 6‐ to 10‐month‐old infants (N = 66) from English‐speaking households in London, Ontario, Canada to discriminate between auditory stimuli of native Russian‐speaking and native English‐speaking mothers speaking or singing to their infants. Infants listened significantly longer to the sung stimuli compared to the spoken stimuli. This is the first study to demonstrate that, even in the absence of other multimodal cues, infant listeners are able to discriminate between sung and spoken stimuli, and furthermore, prefer to listen to sung stimuli over spoken stimuli.