Table 31.4 Differential person functioning DPF fit summary

Table 31.4 summarizes the CLASS Differential Person Functioning statistics for each person shown in Table 31.2. Table 31.2 shows a t-statistic for each CLASS. These are summarized as chi-square statistics for each person, indicating whether the observed DPF within each person is due to chance alone. The null hypothesis is that the DPF is statistically zero across the classes. Please do not use anchoring  (IAFILE=, PAFILE=, SAFILE=) when investigating this Table.


DPF class/group specification is: DPF=$S1W1


| TAP        SUMMARY DPF               BETWEEN-CLASS       KID               |

| CLASSES    CHI-SQUARE   D.F.  PROB.  MEAN-SQUARE t=ZSTD  Number Name       |


|       2         .2914      1  .5893       .2291  -.3520       1 Adam    M  |


TAP CLASSES/GROUPS is the count of item CLASSES or GROUPS for the person.

SUMMARY DIF CHI-SQUARE is the sum of the squared normalized t-statistic values from Table 31.2.

D.F. is the degrees of freedom, the count of CLASSES or GROUPS contributing to the chi-square less 1.

PROB. is the probability of the chi-square. Values less than .05 indicate statistical significance.


BETWEEN-CLASS/GROUP are Between-Group Fit Statistics, testing the hypothesis: "The dispersion of the group measures accords with Rasch model expectations."

MEAN-SQUARE is chi-square divided by its degrees of freedom. It is the size of the misfit (expectation = 1.0, overfit <1.0, underfit >1.0).

t=ZSTD is the significance of the MEAN-SQUARE standardized as a unit-normal deviate (t-statistic with infinite degrees of freedom).


KID is the person. Number is the person entry number. Name is the person label.

Help for Winsteps Rasch Measurement Software: Author: John Michael Linacre

For more information, contact or use the Contact Form

Facets Rasch measurement software. Buy for $149. & site licenses. Freeware student/evaluation download
Winsteps Rasch measurement software. Buy for $149. & site licenses. Freeware student/evaluation download

State-of-the-art : single-user and site licenses : free student/evaluation versions : download immediately : instructional PDFs : user forum : assistance by email : bugs fixed fast : free update eligibility : backwards compatible : money back if not satisfied
Rasch, Winsteps, Facets online Tutorials


Forum Rasch Measurement Forum to discuss any Rasch-related topic

Click here to add your email address to the Winsteps and Facets email list for notifications.

Click here to ask a question or make a suggestion about Winsteps and Facets software.

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
Winsteps Tutorials Facets Tutorials Rasch Discussion Groups



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),



Our current URL is

Winsteps® is a registered trademark



John "Mike" Linacre, author of Winsteps, and Jenny use and recommend eco-friendly, safe and effective wellness and beauty products such as skincare