1. Data are presumed valid and useful, so that subsequent analysis will be productive and results informative. While effort is usually given to careful collection of data, systematic checking for data quality is often omitted. When quality control is skimped, results are suspect.
2. Collecting data asserts that what is utilized has already passed scrutiny. It suggests that data is already in a pristine, though unsubstantiated, state. Is this presuming too much? Does collecting data provide what is required or does it open the door to contamination? Examine the word "collecting". It means gathering together or assembling. Does this define the quality needed for data? Hardly. This process is questionable.
3. Manufacturing data describes the process we require. We do not "find" useful data by beach-combing. Data do not exist in nature. They are manufactured for the occasion. To suggest otherwise implies that data can be found laying around in their natural state, waiting to be picked up by those who stumble upon them. Data are fictitious, standing for instances of information in the solution to a problem, produced from a sample, and inferred to a population. While everyone realizes we cannot know the parameters, few would want to doubt the statistics computed from their own data. Yet we should be doubtful, and the only way to assuage that doubt is scrupulously to address the manufacturing.
6. The production of data requires scrutiny. We have an idea, then an intention. We plan and carry out a strategy. We choose the specifications and manufacture according to our intentions. The process of data manufacture should be no less rigorous than subsequent data analysis. Quality control over production is absolutely necessary. We should keep records on data manufacturing and monitor the process with control charts. Rasch measurement strategies have always stressed data scrutiny. The examination of item and persons records, fit analyses and data plots are some of the tools by which Rasch measurement monitors the quality of manufactured data.
Mark H. Stone
Adler School of Professional Psychology
Data: Collecting or manufacturing? Stone M.H. Rasch Measurement Transactions, 1996, 10:3 p. 517.
|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|
|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.
|Coming Rasch-related Events|
|Apr. 14-17, 2020, Tue.-Fri.||International Objective Measurement Workshop (IOMW), University of California, Berkeley, https://www.iomw.org/|
|May 22 - June 19, 2020, Fri.-Fri.||On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com|
|June 26 - July 24, 2020, Fri.-Fri.||On-line workshop: Practical Rasch Measurement - Further Topics (E. Smith, Winsteps), www.statistics.com|
|June 29 - July 1, 2020, Mon.-Wed.||Measurement at the Crossroads 2020, Milan, Italy , https://convegni.unicatt.it/mac-home|
|July - November, 2020||On-line course: An Introduction to Rasch Measurement Theory and RUMM2030Plus (Andrich & Marais), http://www.education.uwa.edu.au/ppl/courses|
|July 1 - July 3, 2020, Wed.-Fri.||International Measurement Confederation (IMEKO) Joint Symposium, Warsaw, Poland, http://www.imeko-warsaw-2020.org/|
|Aug. 7 - Sept. 4, 2020, Fri.-Fri.||On-line workshop: Many-Facet Rasch Measurement (E. Smith, Facets), www.statistics.com|
|Oct. 9 - Nov. 6, 2020, Fri.-Fri.||On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com|
|June 25 - July 23, 2021, Fri.-Fri.||On-line workshop: Practical Rasch Measurement - Further Topics (E. Smith, Winsteps), www.statistics.com|
The URL of this page is www.rasch.org/rmt/rmt103g.htm