IDFILE= item deletion file

Deletion or selection of items from a test for an analysis, but without removing the responses from your data file, is easily accomplished by creating a file in which each line contains the sequence number or numbers of items to be deleted or selected. Specify this file by means of the control variable, IDFILE=, or enter the deletion list in the control file using IDFILE=*. Your control file should include item labels for all items, including the ones you are deleting. It has the same functionality as IDELETE=. ISELECT= is another way of deleting items. IDFILE=filename can be action from the Specification menu dialog box.


IDFILE= file name

file containing list of item entry numbers to be deleted or reinstated. Each line in the file is in the IDELETE= format


opens a Browser window to find the file


in-line list in the control file

IDFILE=* 4 18-23 *

At the Extra Specifications prompt


In the Specifications Menu dialog box, reinstates all temporary deletions


a) Delete an item: enter the item number. E.g., to delete item 5, enter



b) Delete a range of items: enter the starting and ending item number on the same line separated by a blank or dash. E.g., to delete items 13 through 24



 13 24


c) Select an item for analysis: enter a plus sign then the number.

E.g., to select item 19 from a previously deleted range



d) Select a range of items for analysis: enter a plus sign, the starting number, a blank or dash, then the ending number. E.g., to select items 17 through 22



 +17 22


e) If a + selection is the first entry in the deletion file, then all items are deleted before the first selection is undertaken, so that the items analyzed will be limited to those selected, e.g,

if +10-20 is the only line in the item deletion file for a 250 item test, it means

 1-250  ; delete all 250 items

 +10-20 ; reinstate items 10 through 20.


f) You may specify an item deletion list in your control with






 17  ; delete item 17

 2  ; delete item 2



g) each line can have multiple instructions:


17 2 +10




Item Deletion and Reinstatement Sequence

Control File or at Extra Specifications: Order of Processing

Here, 123 is an example item entry number. It can be any item entry number.


+123 deletes all items only if it is the first deletion instruction in the first of these deletion commands that is active. +123 always reinstates item 123.

IDFILE=* list * or filename



selects the specified items and permanently deletes all other items

Specification Menu Dialog Box

IDELETE=(nothing), IDFILE=(nothing)

reinstates all temporary deletions

ISELECT=(nothing) or ISELECT=*

reinstates all temporary deselections

IDELETE=list, IDFILE=filename

temporary deletions, in addition to previous temporary deletions, if any. If the first deletion instruct starts +123 then temporarily deletes all items and  reinstates item 123 if not permanently deleted


temporary deselections, in addition to previous temporary deselections, if any


Example 1: You wish to delete the fifth and tenth through seventeenth items from an analysis, but then keep item fourteen.

1. Create a file named, say, ITEM.DEL

  2. Enter into the file, the lines:





3. Specify, in the control file,







 or, specify in the control file,











Example 2: The analyst wants to delete the most misfitting items reported in Table 10.

1. Set up a standard control file.

2. Specify



3. Copy the target portion of Table 10.

4. Paste it between the "*"

5. Delete characters before the entry numbers.

6. Type ; after the entry numbers to make further numbers into comments.


TITLE = 'Example of item deletion list from Table 10'


Delete the border character before the entry number

; ENTRY   RAW                            INFIT     OUTFIT             

;   NUM  SCORE  COUNT  MEASURE  ERROR MNSQ  ZSTD MNSQ  ZSTD PTBSE  ACTS                            G  

      5 ; 2     4      .00     1.03 1.48   1.8 1.50   1.8 A-.83  FIND BOTTLES AND CANS           0  

      8 ; 2     4      .00     1.03 1.40   1.6 1.43   1.6 B-.71  LOOK IN SIDEWALK CRACKS         0  

      4 ; 3     4      .00      .62 1.33    .7 1.49    .9 C-.21  WATCH GRASS CHANGE              0  

      9 ; 4     4      .00      .74 1.51    .8 1.57    .9 D-.59  LEARN WEED NAMES                0  

     20 ; 1     4      .00     1.03 1.12    .5 1.14    .6 E-.05  WATCH BUGS                      0  

     24 ; 6     4      .30     1.03 1.15    .6 1.13    .5 F-.15  FIND OUT WHAT FLOWERS LIVE ON   0

Enter the ; to make details to right of entry numbers into comments



Example 3: The analyst want to delete item 4 and items 18 to 23 on the DOS control (or Extra Specifications) line:

Extra specifications? IDFILE=* 4 18-23 * (Enter)




Example 3. In Winsteps analyses, the data file is not changed.


1. To delete items or persons:

IDFILE= (list of item entry numbers)

PDFILE= (list of person entry numbers)


2. To edit the data file:


(person entry number) (item entry number) (new data value or missing)


For instance in an analysis of Exam1.txt, we can place these instructions in the Winsteps control file:



4   ; delete item 4

8   ; delete item 8




6   ; delete person 6




1 2 0   ; person 1 on item 2 scored a 0

3 4 -1 ; person 3 on item 4 scored -1 = missing, not administered


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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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