GRFILE= probability curve coordinate output file

If GRFILE=filename is specified, a file is output which contains a list of measures relative to item difficulty (x-axis coordinates) and corresponding expected scores and category probabilities (y-axis coordinates) to enable you to use your own plotting program to produce item-category plots like those in the Graphs menu.


GRFILE=? opens a Browse window


Column Heading

Column Contents

Fixed Columns

ITEM (or ITEM= value)

An example item number from the response-structure grouping - see ISGROUPS=


MEAS (Measure)

The measure relative to item difficulty (user-rescaled by USCALE=) with UDECIMALS= decimal places. Add the item difficulty to MEAS for absolute measure relative to the latent variable.

The plotted range is at least MRANGE= away from its center.


SCOR (Score)

Expected score for the Modeled Item Characteristic Curve (ICC) or Item Response Function (IRF).


INFO (Information)

Statistical information for Item Information Function. Sum these for all items for the Test Information Function (TIF).


0 (Category number)

Probability of observing lowest category


1, 2, etc.  (Category numbers)

Probability of observing higher categories


If CSV=Y, values are separated by commas. When CSV=T, values are separated by tab characters.


For the numbers plotted for empirical ICCs, see the "Empirical ICC" plot, "Copy data to Clipboard"


Example 1: You wish to write a file on disk called "MYDATAGR.txt" containing x- and y-coordinates for plotting your item's category response curves and its item information function.




With CSV=Y


"PROBABILITY CURVES FOR LIKING FOR SCIENCE (Wright & Masters p.18) Jul  4 16:03 2000"









With CSV=N (fixed spacing)


; PROBABILITY CURVES FOR LIKING FOR SCIENCE (Wright & Masters p.18) Nov 23 23:31 2008

   ACT   MEAS   SCOR   INFO      0      1      2

     1  -3.00    .11    .10    .89    .10    .00

     1  -2.94    .12    .11    .89    .11    .00

     1  -2.88    .12    .11    .88    .12    .00

     1  -2.82    .13    .12    .87    .12    .00

     1  -2.76    .14    .12    .87    .13    .00


Example 2: I want the information function for every item in my test relative to the latent variable (absolute x-axis). All my items share the same rating scale.


1. output the IFILE= to Excel

2. delete all columns except the item difficulties

3. transpose the item difficulties into a row


4. output the GRFILE= to Excel

5. delete unwanted columns and unwanted top row

6. move MEAS into the first column, INFO in the second column.

7. insert two blank rows at the top

8. copy the item difficulty row from the IFILE worksheet into the top row of the GRFILE= worksheet starting in the third column

9. in each cell of the (information x item difficulty) rectangle, add the item difficulty from row 1 to the MEAS value in column 1

10. for each item, plot the INFO (column 2, same for all items)  against the item's difficulty (MEAS) column

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