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
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file containing list of item entry numbers to be deleted or reinstated. Each line in the file is in the IDELETE= format
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IDFILE = ?
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opens a Browser window to find the file
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IDFILE = *
4
18-23
6 5.23
*
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in-line list in the control file
delete item entry number 4
delete item entry number 18 to 23
second number 5.23 is ignored, so that IWEIGHT= can be changed to IDFILE=
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IDFILE=* 4 18-23 *
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At the Extra Specifications prompt
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IDFILE=
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In the Specifications Menu dialog box, reinstates all temporary deletions
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a) Delete an item: enter the item number. E.g., to delete item 5, enter
5
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
or
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
+19
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
or
+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
IDFILE=*
(List)
*
e.g.,
IDFILE=*
17 ; delete item 17
2 ; delete item 2
*
g) each line can have multiple instructions:
IDFILE=*
17 2 +10
3
*
Item Deletion and Reinstatement Sequence
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Control File or at Extra Specifications: Order of Processing
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Here, 123 is an example item entry number. It can be any item entry number.
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IDELETE=list
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+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.
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IDFILE=* list * or filename
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IDELQU=Yes
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ISELECT=selection
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selects the specified items and permanently deletes all other items
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Specification Menu Dialog Box
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IDELETE=(nothing), IDFILE=(nothing)
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reinstates all temporary deletions
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ISELECT=(nothing) or ISELECT=*
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reinstates all temporary deselections
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IDELETE=list, IDFILE=filename
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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
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ISELECT=selection
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temporary deselections, in addition to previous temporary deselections, if any
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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:
5
10-17
+14
3. Specify, in the control file,
NI=50
ITEM1=63
IDFILE=ITEM.DEL
TABLES=1110111
&END
or, specify in the control file,
NI=50
ITEM1=63
IDFILE=*
5
10-17
+14
*
TABLES=1110111
&END
Example 2: The analyst wants to delete the most misfitting items reported in Table 10.
1. Set up a standard control file.
2. Specify
IDFILE=*
*
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'
IDFILE = *
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)
or
C:>Winsteps CONTROL.FIL OUTPUT.FIL IDFILE=* 4 18-23 *
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:
EDFILE=
(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:
IDFILE=*
4 ; delete item 4
8 ; delete item 8
*
PDFILE=-*
6 ; delete person 6
*
EDFILE=*
1 2 0 ; person 1 on item 2 scored a 0
3 4 -1 ; person 3 on item 4 scored -1 = missing, not administered
*
