BEN'S "STABILITY THEOREM"

Rasch ability BG of group G to solve a problem of Rasch difficulty D is

STABLE

i.e. ROBUST against: interval merging, unbiased migration, multiple entry, joint effort and hierarchical regrouping

IF AND ONLY IF

BG - D = λ(BP - D) + (1 - λ)(BT - D)

0 < λ < 1

(BP - D) = Σ(Bn - D)/N + loge N for n=1,N

(BT - D) = Σ(Bn - D) for n=1,N

Benjamin D. Wright's Handout, June 21, 1998. P=Pack, T=Team, N=Group size


Benjamin D. Wright's "Stability Theorem" … B.D. Wright, Rasch Measurement Transactions, 2009, 22:4, 1182



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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