Just What Do You Mean ... ?

The wording of a questionnaire may appear clear and precise, yet convey different meanings to different respondents. Although the purpose of Rasch analysis is to construct generalizable measures along the variable of interest, the measures by themselves have no value if it is unclear what is being measured.

Bookstein and Lindsay (B&L, 1989) investigate this problem by designing a questionnaire to discover what respondents understand by a question frequently asked in their specialty of Library Science. The question is "How often do you use a library?" The answers received to this question from the general public, library clients and other relevant audiences are crucial to assignment of resources in libraries and to the livelihood of librarians.

But what is "library use"? B&L formulate 15 probes into this concept, each starting with "Would you say you used a library today if ... ?" They administered these probes to 33 students, "S", at a Library Graduate School, 4 librarians, "L", and 5 non-librarians, "N".

Their results are summarized in the Figure. The 0-to-10 logit scale measures strictness of interpretation with 10 being most strict and 0 most loose. Each "L", "N" or "S" indicates one person. Placement in the Figure indicates that the person tends to agree that activities listed above are library users, but activities listed below are not. The lowest "N" responded that all activities are library uses. Librarians are located on the lower, loose side in interpreting "library use" (as it is in their own interest to be!). Non-librarians exhibit a "black or white" interpretation, being towards one or other end of the person distribution. Students' interpretations cover the spectrum.

Everyone agreed that "library use" includes the "major" traditional library-centered activities of reading articles, referring to card catalogs, conducting online searches and checking out books. Below this, three strata can be identified, based on how intensively library-specific resources are employed. "Minor" use is when no intentional reading of library material occurs. "Petty" use covers other activities in which, at best, only incidental benefit is obtained from traditional library material. "Building" use is that for which any convenient public building would suffice.

This study illustrates how important shared understanding is to the construction of measures and, hence, knowledge. A simple question, such as "How often do you use a library?", has a spectrum of different meanings to different respondents. Since complete commonality of understanding is unobtainable, another attribute of sound measurement, replication, must be its substitute. Through asking variations on the same question, in different ways and with different intensities, the answer to the researcher's intended query can be constructed step-by-step.

Abraham Bookstein 1994 RMT 8:1 P.333

Bookstein A & Lindsay A (1989) Questionnaire ambiguity: a Rasch scaling model analysis. Library Trends 38:2 p. 215-236.

Figure:

Just what do you mean ...? Bookstein A. … Rasch Measurement Transactions, 1994, 8:1 p.333

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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