Medieval Measurers

Definition of Objective Measurement

Objective measurement is the repetition of a unit amount that maintains its size, within an allowable range of error, no matter which instrument, intended to measure the variable of interest, is used and no matter who or what relevant person or thing is measured.

An objective measurement estimate of amount stays constant and unchanging (within the allowable error) across the persons measured, across different brands of instruments, and across instrument users. The goal of objective measurement is to produce a reference standard common currency for the exchange of quantitative value, so that all research and practice relevant to a particular variable can be conducted in uniform terms. Objective measurement research tests the extent to which a given number can be interpreted as indicating the same amount of the thing measured, across persons measured, and brands of instrument.

Our intuitions about measurement are confirmed with everyday trips to the grocery store. For instance, when selecting apples from a bin, one may readily see that three large apples might contain twice as much edible fruit as three small ones. To account for this difference, the cost is not proportionate with the actual, concrete number of apples, but with their abstract weight.

Most measurement efforts in the human sciences tally differently sized test or survey answers and stop there, mistakenly treating these concrete counts as abstract measures of amount. Over 70 years of objective measurement research and practice have established conclusively 1) the viability of scaling different instruments intended to measure a common variable onto a single reference standard ruler, and 2) the value of developing objective measurement-based construct theories.

The extent to which the unit amount remains constant within a particular range of error cannot be assumed. Research in objective measurement is largely a matter of asserting and testing hypotheses concerning the quantitative status of psychosocial variables. Such research might begin from an instrument, data, a theory, or some combination of these, but proceeds in a manner that uses each of these to check and improve the other two.

Objective measurement can be achieved and maintained employing a wide variety of approaches and methods. These include testing for concatenation, conjoint additivity, Guttman ordering, infinite divisibility, parameter separation or sufficiency. Objective measurement operates within the research traditions of fundamental measurement theory, item response theory, and latent trait theory.

Written by the Program Committee of the Institute for Objective Measurement. December 2000.



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

To be emailed about new material on www.rasch.org
please enter your email address here:

I want to Subscribe: & click below
I want to Unsubscribe: & click below

Please set your SPAM filter to accept emails from Rasch.org

www.rasch.org welcomes your comments:
Please email inquiries about Rasch books to books \at/ rasch.org

Your email address (if you want us to reply):

 

FORUMRasch Measurement Forum to discuss any Rasch-related topic

Coming Rasch-related Events
Feb. 17-19, 2016, Wed.-Fri. In-person workshop: Einführung in die Itemanalyse mit dem Rasch-Modell (T. Salzberger, RUMM), Vienna, Austria, Announcement
Feb. 29 - June 24, 2016, Mon.-Fri. On-line course: Advanced course in Rasch Measurement Theory EDUC5606 (D. Andrich, RUMM2030), www.education.uwa.edu.au
March 2-4, 2016, Wed.-Fri. In-person workshop: Introductory Rasch (M. Horton, RUMM), Leeds, UK, www.leeds.ac.uk/medicine/rehabmed/psychometric
March 18, 2016, Fri. UK Rasch User Group Meeting, Durham, UK, www.rasch.org.uk
March 23-24, 2016, Wed.-Thur. In-person workshop: Introduction to Rasch using Winsteps (W.Boone), Cincinnati OH, raschmeasurementanalysis.com
April 4-6, 2016, Mon.-Wed. IOMW2016 Conference, International Objective Measurement Workshop, Washington DC, www.iomw.org
April 8-12, 2016, Fri.-Tues. AERA Annual Meeting, Washington DC, www.aera.net
April 27-29, 2016, Wed.-Fri. In-person workshop: IRT/Rasch and CAT using Concerto (R), Cambridge, UK, www.psychometrics.cam.ac.uk/trainingworkshops/
May 11-13, 2016, Wed.-Fri. In-person workshop: Introductory Rasch (M. Horton, RUMM), Leeds, UK, www.leeds.ac.uk/medicine/rehabmed/psychometric
May 16-18, 2016, Mon.-Wed. In-person workshop: Intermediate Rasch (M. Horton. Tennant, RUMM), Leeds, UK, www.leeds.ac.uk/medicine/rehabmed/psychometric
May 27 - June 24, 2016, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com
June 16-19, Thur.-Sat. In-person workshop: Introduction to Rasch measurement analysis in the healthcare sciences and education (in English), Barcelona, Spain ( L. González de Paz, W. Boone, Winsteps), Announcement
July 1 - July 29, 2016, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Further Topics (E. Smith, Winsteps), www.statistics.com
July 30-31, 2016, Sat.-Sun. PROMS 2016 Pre-Conference Workshop, Xi'an, China
Aug. 1-3, 2016, Mon.-Wed. PROMS 2016 Conference, Xi'an, China
Aug. 1 - Nov. 25, 2016, Mon.-Fri. On-line course: Introduction to Rasch Measurement Theory EDU5638 (D. Andrich, RUMM2030), www.education.uwa.edu.au
Aug. 3-5, 2016, Wed.-Fri. IMEKO 2016 TC1-TC7-TC13 Joint Symposium, Berkeley, CA, imeko-tc7-berkeley-2016.org
Aug. 12 - Sept. 9, 2016, Fri.-Fri. On-line workshop: Many-Facet Rasch Measurement (E. Smith, Facets), www.statistics.com
Sept. 2 - Oct. 14, 2016, Fri.-Fri. On-line workshop: Rasch Applications, Part 1: How to Construct a Rasch Scale (W.P. Fisher, Jr.), www.statistics.com
Oct. 14 - Nov. 11, 2016, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com
Jan. 6 - Feb. 3, 2017, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com
May 26 - June 23, 2017, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com
June 30 - July 29, 2017, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Further Topics (E. Smith, Winsteps), www.statistics.com
Aug. 11 - Sept. 8, 2017, Fri.-Fri. On-line workshop: Many-Facet Rasch Measurement (E. Smith, Facets), www.statistics.com
Sept. 28-30, 2016, Wed.-Fri. In-person workshop: Introductory Rasch (M. Horton, RUMM), Leeds, UK, www.leeds.ac.uk/medicine/rehabmed/psychometric
Oct. 3-5, 2016, Mon.-Wed. In-person workshop: Intermediate Rasch (M. Horton. Tennant, RUMM), Leeds, UK, www.leeds.ac.uk/medicine/rehabmed/psychometric
Oct. 6-7, 2015, Thur.-Fri. In-person workshop: Advanced Rasch (M. Horton, RUMM), Leeds, UK, www.leeds.ac.uk/medicine/rehabmed/psychometric
Oct. 13 - Nov. 10, 2017, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com
Jan. 5 - Feb. 2, 2018, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com
May 25 - June 22, 2018, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com
June 29 - July 27, 2018, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Further Topics (E. Smith, Winsteps), www.statistics.com
Aug. 10 - Sept. 7, 2018, Fri.-Fri. On-line workshop: Many-Facet Rasch Measurement (E. Smith, Facets), www.statistics.com
Oct. 12 - Nov. 9, 2018, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com
Dec. 7-9, 2016, Wed.-Fri. In-person workshop: Introductory Rasch (M. Horton, RUMM), Leeds, UK, www.leeds.ac.uk/medicine/rehabmed/psychometric
The HTML to add "Coming Rasch-related Events" to your webpage is:
<script type="text/javascript" src="http://www.rasch.org/events.txt"></script>