Example 2: Control and anchor files |
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A control file, EXAM2.TXT, for the analysis of a test containing 18 items, each item already scored dichotomously as 0,1. The person-id data begins in column 1 and the item-response string begins in column 11. The standard tables will be appear in the printout. There is user scaling. Items 2, 4, 6 and 8 are anchored at 400, 450, 550 and 600 units respectively, supplied in file EXAM2IAF.TXT Your data is in file EXAM2DAT.TXT:
; This file is EXAM2.TXT
TITLE='KNOX CUBE TEST - ANCHORED' ; the title for output
NI=18 ; the number of items
ITEM1=11 ; position of first response in data record
NAME1=1 ; first column of person-id in data record
PERSON=KID
ITEM=TAP
DATA=EXAM2DAT.TXT ; name of data file
IAFILE=EXAM2IAF.TXT ; this is item anchor (input) file: it is the IFILE= of an earlier analysis
CONVERGE=L ; use only Logits for convergence criterion
LCONV=.005 ; converged when biggest change is too small to show on any report.
; What follows is equivalent to the IAFILE= above
; IAFILE=* ; item anchor file list
;2 400 ; item 2 anchored at 400 units
;4 450 ; item 4 anchored at 450 units
;6 550 ; item 6 anchored at 550 units
;8 600 ; item 8 anchored at 600 units
; *
UIMEAN=500 ; user scaling - item mean
USCALE=100 ; user scaling - 1 logit = 100 user units
UDECIM=0 ; print measures without decimals
&END
1-4 ; item labels, starting with the first item
.
4-1-3-4-2-1-4
END NAMES ; End of this file
The anchoring information is contained in file EXAM2IAF.TXT and contains the following lines, starting in column 1:
2 400 ; item 2 anchored at 400 units:
; if logits are user-rescaled, then anchor values are also expected to be user-rescaled.
; for logit anchor values, specify UASCALE=1
4 450 ; item 4 anchored at 450 units
6 550 ; item 6 anchored at 550 units
8 600 ; item 8 anchored at 600 units
Item calibration files, IFILE=, from prior runs can be used as item anchor files, IAFILE=, of later runs.
Your data is in the separate file, EXAM2DAT.TXT, with person-id starting in column 1, and item responses starting in column 11:
Richard M 111111100000000000
Tracie F 111111111100000000
.
Elsie F 111111111101010000
Helen F 111000000000000000 End of this file