Communicating Measurement

An innovative and powerful way to communicate measurement information is displayed overleaf. It comes from W. Zhu and E.L. Cole, Many-facet Rasch calibration of a gross-motor instrument, to appear in Research Quarterly for Exercise and Sport.

The item map is in the center of the picture (in printed text). There are two content areas in Ulrich's "Test of Gross Motor Development": Objective Control and Locomotor Skill. Within each area there are several strands: Kicking, Bouncing, Throwing, etc. Within each strand there are several test items. For Kicking, they are 1, 2, 3, 4. Each test item is positioned at its logit calibration. There are some easy Kicking, Jumping, Galloping and Running items, but no especially hard ones. (For general use, the logit scale could be linearly transformed into "GroMo" units, with a conversion GroMo = 6*logit + 47. Then the displayed range across the page would be 5 to 95, instead of -7 to +8.)

To use this map as a self-measuring instrument, mark an / or x at each item administered to the child directly onto the item map. (The printed item map shows what happened when a child was administered the whole test: each success is marked with a (), each failure with a ^.) Then draw by eye a vertical line down the map summarizing the child's overall level of performance on the test. (The dotted line shown on the map does this for the example child). A / or x placed far from the vertical line flags an unexpected strength or weakness. (The ^ on Item 2 in Galloping is a conspicuous weakness of the example child).

Extend your vertical line down to meet the familiar ogival test characteristic curve in the bottom panel. This is positioned to align with the measurement scale of the central panel. Now you can read off a predicted raw score on the complete test, even when only a few items have been administered!

Extend your vertical line up to the normative curves in the top panel, which are a series of person maps summarizing the typical range of child performances at each year of age. The vertical line in the picture identifies a 7 year-old performing slightly above average. Note how, in Ulrich's data, the 6 year-olds were more homogeneous than the 5 or 7 year-olds. This reminds us that normative curves are based on samples and so are never completely general "truths".

The symbols in the center panel of the Figure are test items.

Communication measurement. Zhu W. … Rasch Measurement Transactions, 1995, 9:2 p.437

Rasch Books and Publications
Invariant Measurement: Using Rasch Models in the Social, Behavioral, and Health Sciences, 2nd Edn. George Engelhard, Jr. & Jue Wang	Applying the Rasch Model (Winsteps, Facets) 4th Ed., Bond, Yan, Heene	Advances in Rasch Analyses in the Human Sciences (Winsteps, Facets) 1st Ed., Boone, Staver	Advances in Applications of Rasch Measurement in Science Education, X. Liu & W. J. Boone	Rasch Analysis in the Human Sciences (Winsteps) Boone, Staver, Yale
Introduction to Many-Facet Rasch Measurement (Facets), Thomas Eckes	Statistical Analyses for Language Testers (Facets), Rita Green	Invariant Measurement with Raters and Rating Scales: Rasch Models for Rater-Mediated Assessments (Facets), George Engelhard, Jr. & Stefanie Wind	Aplicação do Modelo de Rasch (Português), de Bond, Trevor G., Fox, Christine M	Appliquer le modèle de Rasch: Défis et pistes de solution (Winsteps) E. Dionne, S. Béland
Exploring Rating Scale Functioning for Survey Research (R, Facets), Stefanie Wind	Rasch Measurement: Applications, Khine	Winsteps Tutorials - free Facets Tutorials - free	Many-Facet Rasch Measurement (Facets) - free, J.M. Linacre	Fairness, Justice and Language Assessment (Winsteps, Facets), McNamara, Knoch, Fan
Other Rasch-Related Resources: Rasch Measurement YouTube Channel
Rasch Measurement Transactions & Rasch Measurement research papers - free	An Introduction to the Rasch Model with Examples in R (eRm, etc.), Debelak, Strobl, Zeigenfuse	Rasch Measurement Theory Analysis in R, Wind, Hua	Applying the Rasch Model in Social Sciences Using R, Lamprianou	El modelo métrico de Rasch: Fundamentación, implementación e interpretación de la medida en ciencias sociales (Spanish Edition), Manuel González-Montesinos M.
Rasch Models: Foundations, Recent Developments, and Applications, Fischer & Molenaar	Probabilistic Models for Some Intelligence and Attainment Tests, Georg Rasch	Rasch Models for Measurement, David Andrich	Constructing Measures, Mark Wilson	Best Test Design - free, Wright & Stone Rating Scale Analysis - free, Wright & Masters
Virtual Standard Setting: Setting Cut Scores, Charalambos Kollias	Diseño de Mejores Pruebas - free, Spanish Best Test Design	A Course in Rasch Measurement Theory, Andrich, Marais	Rasch Models in Health, Christensen, Kreiner, Mesba	Multivariate and Mixture Distribution Rasch Models, von Davier, Carstensen

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