Making Metrics Less Arbitrary

"A metric, once made meaningful, can be used to provide perspectives about such things as the magnitude of change that occurs on an underlying dimension as a function of an intervention. Evidence that an intervention causes movement along a scale that has nonarbitrary meaning can reveal the real-world consequences of this change."

"It can be difficult and time consuming to conduct the research needed to make a metric less arbitrary. Fortunately, the issue of metric arbitrariness is irrelevant for many research goals, so not all researchers must tackle this issue. ... However, there are applied situations in which researchers need to address the issue if they are going to fulfill their research goals. Tying metrics to meaningful, real-word events provides a viable means of making metrics less arbitrary, but there will always be some guesswork involved. No new methodology is going to expose psychological constructs to the naked eye. Best estimates of where people stand on psychological dimensions are always that, estimates. Nevertheless, awareness of this limitation is of value to the psychologist. A researcher who appreciates the gap between a psychological metric and a psychological reality knows to look past a person's score and search for something meaningful."

Blanton, H., and J. Jaccard. 2006. Arbitrary metrics in psychology. American Psychologist 61 (January):27-41.

Journal of Applied Measurement: Volume 7, Number 3. Fall 2006

Measuring Teacher Ability with the Rasch Model by Scaling a Series of Product and Performance Tasks. Judy R. Wilkerson and William Steve Lang

An Introduction to the Theory of Unidimensional Unfolding. Andrew Kyngdon

Estimating Person Locations from Partial Credit Data Containing Missing Responses. R. J. De Ayala

Validation of a Questionnaire Used to Assess Safety and Professionalism among Arborists. Steven G. Viger, Edward W. Wolfe, Hallie Dozier, and Krisanna Machtmes

How Accurate Are Lexile Text Measures? A. Jackson Stenner, Hall Burdick, Eleanor E. Sanford, and Donald S. Burdick

Rasch Analysis of the Structure of Health Risk Behavior in South African Adolescents. Elias Mpofu, Linda Caldwell, Edward Smith, Alan J. Fisher, Christine Mathews, Lisa Wagner, and Tania Vergnani

Understanding Rasch Measurement: Multicomponent Latent Trait Models for Complex Tasks. Susan E. Embretson and Xiangdong Yang

RMT 20:1 Miscellaneous Material, … Rasch Measurement Transactions, 2006, 20:1

Rasch Publications
Rasch Measurement Transactions (free, online)	Rasch Measurement research papers (free, online)	Probabilistic Models for Some Intelligence and Attainment Tests, Georg Rasch	Applying the Rasch Model 3rd. Ed., Bond & Fox	Best Test Design, Wright & Stone
Rating Scale Analysis, Wright & Masters	Introduction to Rasch Measurement, E. Smith & R. Smith	Introduction to Many-Facet Rasch Measurement, Thomas Eckes	Invariant Measurement: Using Rasch Models in the Social, Behavioral, and Health Sciences, George Engelhard, Jr.	Statistical Analyses for Language Testers, Rita Green
Rasch Models: Foundations, Recent Developments, and Applications, Fischer & Molenaar	Journal of Applied Measurement	Rasch models for measurement, David Andrich	Constructing Measures, Mark Wilson	Rasch Analysis in the Human Sciences, Boone, Stave, Yale
in Spanish:	Análisis de Rasch para todos, Agustín Tristán		Mediciones, Posicionamientos y Diagnósticos Competitivos, Juan Ramón Oreja Rodríguez

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