Validity by Numbers vs. Validity by Theory

Robert L. Ebel: "These observations suggest that the concept of validity itself may be weak scientifically. Most of the definitions of validity can be shown to be derived from the basic notion that validity is the degree to which a test measures what it is supposed to measure. But how does one know what a test is supposed to measure? On a superficial level, perhaps, it may be suggested by the test title - academic aptitude, mathematics achievement, or social studies background, for example - but these suggestions are by no means definitive.

"Does the criterion [i.e., definitive information outside the test] tell us what the test is supposed to measure? It might, if criteria were given to us. Usually they are not. They have to be devised, often after the test itself was constructed. Toops (1944) has said:

Possibly as much time should be spent in devising the criterion as in constructing and perfecting the test. This important part of a research seldom receives half the time or attention it requires or deserves. If the criterion is slighted the time spent on the tests is, by so much, largely wasted.

"The ease with which test developers can be induced to accept as criterion measures quantitative data [for test validation by correlation], having the slightest appearance of relevance to the trait being measured is one of the scandals of psychometry. To borrow a figure of speech from Thorndike (1922), they will use the loudness of the thunder as a criterion for their measurements of the voltage of the lightning."

Ebel R. L. (1961) Must all tests be valid? American Psychologist, 16, 640-7, reprinted in p.222-3 in W. A. Mehrens & R. L. Ebel (Eds.) Principles of Educational and Psychological Measurement. Chicago: Rand McNally. 1967.

Thorndike E.L. (1922) Measurement in education. 21^st Yearbook, NSSE. Bloomington, Il: Public School Publishing Co.

Toops H. A. (1944) The criterion. Educ. Psychol. Meas., 4, 271-297.

Music is the art of measuring well.

Augustine of Hippo

Validity by Theory Ebel, R.L. Validity by Numbers vs. … Rasch Measurement Transactions, 1999, 13:3 p. 713

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

Forum

Rasch Measurement Forum to discuss any Rasch-related topic

Go to Top of Page
Go to index of all Rasch Measurement Transactions
AERA members: Join the Rasch Measurement SIG and receive the printed version of RMT
Some back issues of RMT are available as bound volumes
Subscribe to Journal of Applied Measurement

Go to Institute for Objective Measurement Home Page. The Rasch Measurement SIG (AERA) thanks the Institute for Objective Measurement for inviting the publication of Rasch Measurement Transactions on the Institute's website, www.rasch.org.

The URL of this page is www.rasch.org/rmt/rmt133r.htm

Website: www.rasch.org/rmt/contents.htm