Table 12 Bias Summary Report

Zscore=, Bias= and Xtreme= control Table 12. One table is produced for each bias estimation. Each entry in the table is a bar-chart showing the distribution of reported statistics. The scale is from left to right. "M" represents the mean value of the statistic for the facet, "S" is one sample standard deviation each side of the mean, "Q" is two sample standard deviations, and "X" is three.


Table 12 reports the same statistics reported numerically in the later Table 13. So, -4, -3 etc are the numerical values of those statistics (compare with the numerical Table 13). M is the mean, S is one standard deviation away, Q is two standard deviations away.

Bias/Interaction Size = Bias Size (usually in logits) in Table 13

Bias/Interaction Significance = t-value in Table 13




Bias/Interaction Size:



 2  21 1122472485329801372717797531096665273067453 2221111 1   1


-3        -2        -1         0         1         2         3      4


Bias/Interaction Significance:



    11 1 1 11276444773675833557684234395094893331222111  1     1


-5    -4    -3    -2    -1     0     1     2     3     4     5     6


The numbers are frequencies. They are printed vertically. The biggest number for "Bias/Interaction size" is 107. 107 interactions are about 0.1 logits in size. 115 interactions have a bias/interaction significance (t) of about -0.3


The frequencies summarize the full Table of interactions (Table 14) and are useful for seeing the distributional pattern.


In these pictures there are clearly a few outliers needing special attention, but the great majority of interactions are statistically and substantively close to 0.

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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 with Raters and Rating Scales: Rasch Models for Rater-Mediated Assessments, George Engelhard, Jr. & Stefanie Wind 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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Coming Rasch-related Events
April 10-12, 2018, Tues.-Thurs. Rasch Conference: IOMW, New York, NY,
April 13-17, 2018, Fri.-Tues. AERA, New York, NY,
May 22 - 24, 2018, Tues.-Thur. EALTA 2018 pre-conference workshop (Introduction to Rasch measurement using WINSTEPS and FACETS, Thomas Eckes & Frank Weiss-Motz),
May 25 - June 22, 2018, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps),
June 27 - 29, 2018, Wed.-Fri. Measurement at the Crossroads: History, philosophy and sociology of measurement, Paris, France.,
June 29 - July 27, 2018, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Further Topics (E. Smith, Winsteps),
July 25 - July 27, 2018, Wed.-Fri. Pacific-Rim Objective Measurement Symposium (PROMS), (Preconference workshops July 23-24, 2018) Fudan University, Shanghai, China "Applying Rasch Measurement in Language Assessment and across the Human Sciences"
Aug. 10 - Sept. 7, 2018, Fri.-Fri. On-line workshop: Many-Facet Rasch Measurement (E. Smith, Facets),
Sept. 3 - 6, 2018, Mon.-Thurs. IMEKO World Congress, Belfast, Northern Ireland
Oct. 12 - Nov. 9, 2018, Fri.-Fri. On-line workshop: Practical Rasch Measurement - Core Topics (E. Smith, Winsteps),


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